Entity Address, City or Town Entity Address, City or Town Fair Value Disclosures [Abstract] New Accounting Pronouncements Or Change In Accounting Principle [Table] Accounting Standards Update and Change in Accounting Principle [Table] Earnings per share: Earnings Per Share [Abstract] Contract with customer adjustment to revenue impact of changes in estimated claims or incentives over threshold. Contract With Customer Adjustment To Revenue Impact Of Changes In Estimated Claims Or Incentives Over Threshold Impact of changes in estimated claims or incentives on revenue Percentage of bond hedge and warrant transactions increased conversion price Percentage Of Bond Hedge And Warrant Transactions Increased Conversion Price Percentage of bond hedge and warrant transactions increased conversion price. 2026 Finance Lease, Liability, to be Paid, Year Three Issuance of equity securities, net of retirements Stock Issued During Period, Value, New Issues Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Defense And Intelligence Defense And Intelligence [Member] Defense and intelligence. Acquired contract liabilities Contract with Customer, Liability, Increase (Decrease) for Contract Acquired in Business Combination Long-term lease liabilities, operating leases Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Operating Leases Long Term Lease Liabilities Business combination recognized identifiable assets acquired and liabilities assumed operating leases long-term lease liabilities. Schedule of Supplemental Cash Flow Information Related to Leases Schedule Of Cash Flow Information Related To Leases Table [Text Block] Schedule of cash flow information related to leases. Convertible Notes Payable, Total Convertible senior notes Convertible Notes Payable Consecutive trading day period Debt Instrument Convertible Consecutive Business Day Period Debt instrument convertible consecutive business day period. Amendment Flag Amendment Flag Common stock shares outstanding including ESOP Common Stock Shares Outstanding Including Employee Stock Ownership Plan Shares Common stock shares outstanding including employee stock ownership plan shares. Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax, Total Pension adjustments, net Pension adjustments, net of tax Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax Subsequent Event Type Subsequent Event Type [Domain] Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Goodwill, Total Goodwill Beginning Balance Ending Balance Goodwill Deferred tax assets Deferred Income Tax Assets, Net Alleged Violation of False Claims, Act Alleged Violation Of False Claims Act [Member] Alleged Violation Of False Claims Act. Engineered Systems Engineered Systems [Member] Engineered systems. Right of use assets, operating leases Right of use assets, operating leases (including $6,863 and $6,315 Right of use assets, operating leases of consolidated joint ventures) Right-of-use assets Schedule Of Acquired Finite Lived Intangible Asset By Major Class [Table] Schedule of Acquired Finite-Lived Intangible Asset by Major Class [Table] Document Quarterly Report Document Quarterly Report Debt Instrument [Table] Schedule of Long-Term Debt Instruments [Table] Connected Communities Connected Communities [Member] Connected Communities. Repurchases of common stock Payments for Repurchase of Common Stock Less: imputed interest Lessee, Operating Lease, Liability, Undiscounted Excess Amount Lease option to terminate Lessee Lease Option To Terminate Lessee lease option to terminate. Amount paid per month to contractor defendant by relator on false claims Amount Paid Per Month To Contractor Defendant By Relator On False Claims Amount paid per month to contractor defendant by relator on false claims. Statement [Table] Statement [Table] Long-term lease liabilities, operating leases Long-term lease liabilities, operating leases (including $3,871 and $3,763 Long-term lease liabilities, operating leases of consolidated joint ventures) Long-term 2024 Finance Lease, Liability, to be Paid, Year One Interest on lease liabilities Finance Lease, Interest Expense Equity-based compensation expense Equity Based Compensation Income Expense Equity-based compensation income (expense). Subsegments Subsegments [Domain] Change in accounting principle, accounting standards update, immaterial effect Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] Operating cash flows for operating leases Operating Lease, Payments Unconsolidated Joint Ventures Investees Other [Member] Investees Other. Business Acquisition Business Acquisition [Axis] Conversion percentage of stock price trigger Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger Income taxes Increase (Decrease) in Income Taxes Billed Billed Receivables Current Billed receivables current. Description of Operations Nature of Operations [Text Block] Exercise of option by initial purchasers aggregate principal amount Debt Instrument Exercise Of Option By Initial Purchasers Aggregate Principal Amount Debt instrument exercise of option by initial purchasers aggregate principal amount. Payments to Acquire Productive Assets, Total Capital expenditures Payments to Acquire Productive Assets Acquisitions Business Combination Disclosure [Text Block] ASU 2019-12 Accounting Standards Update 2019-12 [Member] Liability for income taxes associated with uncertain tax positions Liability for Uncertainty in Income Taxes, Current Leases Lessee, Operating Leases [Text Block] Schedule of Maturity Analysis of Future Undiscounted Cash Flows Schedule Of Maturities Of Operating And Finance Lease Liabilities Table [Text Block] Schedule of maturities of operating and finance lease liabilities. Operating leases Operating Lease, Weighted Average Remaining Lease Term Total liabilities and shareholders' equity Liabilities and Equity Plan Name Plan Name [Domain] Other liabilities current Other Liabilities, Current Unbilled Unbilled Receivables, Current Right of use assets, operating leases Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Operating Leases Right Of Use Assets Business combination recognized identifiable assets acquired and liabilities assumed operating leases right of use assets. Convertible Debt, Total Net carrying value of notes Convertible Debt Change in accounting principle, accounting standards update, adopted Change in Accounting Principle, Accounting Standards Update, Adopted [true false] Foreign currency translation gain (loss), net Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Income Statement [Abstract] Rest of World Non-US [Member] Basis of Presentation and Principles of Consolidation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Finance leases Finance Lease, Weighted Average Remaining Lease Term Other long-term liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Unconsolidated Joint Ventures Unconsolidated Joint Ventures [Member] Unconsolidated joint ventures. Short-term lease liabilities, operating leases Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Operating Leases Short Term Lease Liabilities Business combination recognized identifiable assets acquired and liabilities assumed operating leases short-term lease liabilities. Mobility Solutions Mobility Solutions [Member] Mobility solutions. Accrued expenses and other current liabilities Finance Lease, Liability, Current Sale of Stock Sale of Stock [Domain] Total current liabilities Current liabilities Liabilities, Current Contract assets (including $9,285 and $11,313 Contract assets of consolidated joint ventures) Contract with Customer, Asset, after Allowance for Credit Loss, Current, Total Contract assets Contract with Customer, Asset, after Allowance for Credit Loss, Current 2026 Lessee, Operating Lease, Liability, to be Paid, Year Three Loss Contingency Nature [Axis] Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest, Total Comprehensive income attributable to noncontrolling interests, net of tax Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Business Acquisition, Acquiree Business Acquisition, Acquiree [Domain] Interest Expense, Total Interest expense Interest Expense Adjustment on unconsolidated joint venture Equity Method Investment Loss Adjustment Amount Equity method investment loss adjustment amount. Trade Name Trade Names Trade Names [Member] Short-term lease cost Short-Term Lease, Cost Contract liabilities Increase (Decrease) in Contract with Customer, Liability Schedule of Gross Amount and Accumulated Amortization of Intangible Assets Schedule of Acquired Finite-Lived Intangible Assets by Major Class [Table Text Block] Proceeds from sales of investments in unconsolidated joint ventures Proceeds from Sale of Equity Method Investments ASU 2021-08 Accounting Standards Update 2021-08 [Member] Return of investments in unconsolidated joint ventures Proceeds from Equity Method Investment, Distribution, Return of Capital Treasury Stock, Shares, Total Treasury stock, shares Treasury Stock, Shares Operating leases Operating Lease, Weighted Average Discount Rate, Percent Investment, Name Investment, Name [Domain] Schedule of Aggregate Amount of Debt Schedule Of Aggregate Amount Debt Repayable Table [Text Block] Schedule of aggregate amount debt repayable. Variable Rate Variable Rate [Axis] Entity Small Business Entity Small Business Number of reportable segments Number of Reportable Segments Accounts payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable Number of annual installments Number Of Annual Installments Number of annual installments. Intangible Assets Intangible Assets Disclosure [Text Block] Direct Costs of Contracts and Selling, General and Administrative Expense Direct Costs Of Contracts And Selling General And Administrative Expense [Member] Direct costs of contracts and selling, general and administrative expense. ASC 2020-06 Accounting Standards Update 2020-06 [Member] Distributions to noncontrolling interests Payments to Noncontrolling Interests Total current assets Current assets Assets, Current Carrying amount of convertible senior notes adjusted in retained earnings Carrying Amount Of Convertible Senior Notes Adjusted In Retained Earnings Carrying amount of convertible senior notes adjusted in retained earnings. Property Plant And Equipment [Line Items] Property, Plant and Equipment [Line Items] Summary of Contract Assets and Contract Liabilities Contract with Customer, Contract Asset, Contract Liability, and Receivable [Table Text Block] 2023 (remaining) Lessee, Operating Lease, Liability, to be Paid, Remainder of Fiscal Year Weighted Average Number of Shares Outstanding, Basic, Total Basic weighted average number of shares outstanding Weighted Average Number of Shares Outstanding, Basic Finance Lease, Liability, Total Total present value of lease liabilities Finance Lease, Liability City Area Code City Area Code Schedule of Debt Schedule of Debt [Table Text Block] Convertible senior notes Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities Total accounts receivable, gross Accounts Receivable, before Allowance for Credit Loss, Current Net Income Available to Shareholders to Compute Basic and Diluted EPS Schedule of Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Table Text Block] IPKeys Power Partners Ipkeys Power Partners [Member] Ipkeys Power Partners. Total liabilities Liabilities Private Placement Private Placement [Member] Document Period End Date Document Period End Date Investments in and Advances to Joint Ventures Equity Method Investments and Joint Ventures Disclosure [Text Block] Construction in Progress Construction in Progress [Member] Effect of exchange rate changes Effect of Exchange Rate on Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Disposal Group, Including Discontinued Operations Contracts Receivable, Claims and Uncertain Amounts, Total Contract assets, unapproved change orders, claims, and requests Contracts Receivable, Claims and Uncertain Amounts New Accounting Pronouncements Or Change In Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Contract assets Increase (Decrease) in Contract with Customer, Asset Contract retentions Contract Receivable Retainage Assets Liabilities Net Contract receivable retainage assets (Liabilities) net. Summary of Business Segment Information Schedule of Segment Reporting Information, by Segment [Table Text Block] 2024 Finite-Lived Intangible Asset, Expected Amortization, Year One Minimum Statistical Measurement Statistical Measurement [Axis] Summary of Financial Information for Unconsolidated Joint Ventures Equity Method Investments [Table Text Block] Schedule of Weighted Average Number of Shares Used To Compute Basic and Diluted EPS Schedule of Weighted Average Number of Shares [Table Text Block] Subsequent Event [Line Items] Subsequent Event [Line Items] Stockholders' Equity Attributable to Noncontrolling Interest, Ending Balance Stockholders' Equity Attributable to Noncontrolling Interest, Beginning Balance Stockholders' Equity Attributable to Noncontrolling Interest, Total Noncontrolling interests Stockholders' Equity Attributable to Noncontrolling Interest Operating cash flows for finance leases Finance Lease, Interest Payment on Liability Related Party Related Party [Axis] Total assets Assets Revenues Related Party Transaction, Other Revenues from Transactions with Related Party Contract with Customer, Asset, after Allowance for Credit Loss, Total Contract assets Contract with Customer, Asset, after Allowance for Credit Loss Decrease in operating income Decrease In Operating Income Decrease in operating income. Long-Term Debt, Excluding Current Maturities, Total Long-term debt Long-Term Debt, Excluding Current Maturities Earnings Per Share, Diluted, Total Diluted Earnings Per Share, Diluted Convertible note converted each amount Convertible Note Converted Each Amount Convertible note converted each amount. Summary of Remaining Unsatisfied Performance Obligations Expect to Satisfy Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block] Entity Address, Postal Zip Code Entity Address, Postal Zip Code Revision of Prior Period Revision of Prior Period [Axis] Document Fiscal Period Focus Document Fiscal Period Focus Convertible Note Hedge And Warrant Transaction Convertible Note Hedge And Warrant Transaction [Member] Convertible note hedge and warrant transaction. Cost of Goods and Services Sold, Total Costs Direct cost of contracts Cost of Goods and Services Sold Finite Lived Intangible Assets Acquired As Part Of Business Combination [Table] Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table] Accounts receivable Increase (Decrease) in Accounts Receivable Revolving Credit Facility Revolving Credit Facility [Member] Deferred tax assets, valuation allowance Deferred Tax Assets, Valuation Allowance APIC, Share-Based Payment Arrangement, Increase for Cost Recognition, Total Stock-based compensation APIC, Share-Based Payment Arrangement, Increase for Cost Recognition Interest Income (Expense), Net, Total Interest expense, net Interest Income (Expense), Net Stock-based awards Incremental Common Shares Attributable to Dilutive Effect of Share-Based Payment Arrangements Interest income Investment Income, Interest Total operating lease liabilities Total present value of lease liabilities Operating Lease, Liability Net cash used in financing activities Net Cash Provided by (Used in) Financing Activities Contributions of treasury stock Other Postretirement Benefits Expense (Reversal of Expense), Noncash Decrease in earnings per share diluted Decrease in earnings per share diluted. Legal Proceedings [Table] Legal Proceedings. Revision of Prior Period, Accounting Standards Update, Adjustment Revision of Prior Period, Accounting Standards Update, Adjustment [Member] Contract with Customer, Basis of Pricing Contract with Customer, Basis of Pricing [Domain] Statement of Financial Position [Abstract] Entity File Number Securities Act File Number Total lease payments Finance Lease, Liability, to be Paid Statement of Cash Flows [Abstract] Long-term employee incentives Long Term Employee Incentives Long-term employee incentives. Schedule of Intangible Assets Value on Purchase Price Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Sublease income Sublease Income Revolving credit facility Line of Credit Facility, Current Borrowing Capacity Borrowed under credit agreement to partially fund the acquisition Business Combination, Consideration Transferred, Liabilities Incurred Buildings and Leasehold Improvements Building and Building Improvements [Member] Geographical Geographical [Domain] Statistical Measurement Statistical Measurement [Domain] Lease existence of option to terminate Lessee Lease Existence Of Option To Terminate Lessee lease existence of option to terminate. Statement of Stockholders' Equity [Abstract] Sale of Stock Sale of Stock [Axis] Percentage change in contract assets and liabilities Contract With Customer Asset Liability Cumulative Catchup Adjustment To Revenue Change In Measure Of Progress Percent Contract with customer asset liability cumulative catchup adjustment to revenue change in measure of progress percent. Accrued expenses and other current liabilities Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Current Liabilities Accrued Expenses And Other Liabilities Business combination recognized identifiable assets acquired and liabilities assumed current liabilities accrued expenses and other liabilities. Total shares retired Stock Repurchased and Retired During Period, Shares Summary of Lease Costs Lease, Cost [Table Text Block] Convertible senior notes if-converted method interest adjustment Dilutive Securities, Effect on Basic Earnings Per Share, Dilutive Convertible Securities Subsequent Events [Abstract] Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Leases Lease Agreements [Member] Long-term Debt, Type Long-Term Debt, Type [Axis] Increase in term loan Debt Instrument, Increase (Decrease), Net Debt Instrument, Increase (Decrease), Net, Total Diluted net income attributable to Parsons Corporation Net Income (Loss) Attributable to Parent, Diluted Deferred Income Tax Expense (Benefit), Total Deferred taxes Deferred Income Tax Expense (Benefit) Deferred tax liabilities Deferred Income Tax Liabilities, Net Schedule of Property and Equipment, Net Property, Plant and Equipment [Table Text Block] Contracts with Customers Revenue from Contract with Customer [Text Block] Adjustment to deferred tax asset through retained earnings Adjustment To Deferred Tax Asset Through Retained Earnings Adjustment to deferred tax asset through retained earnings. Unused term loan commitments rate Unused Term Loan Commitments Rate Unused term loan commitments rate. Antidilutive Securities Antidilutive Securities [Axis] Revolving credit facility Line of Credit Facility, Maximum Borrowing Capacity Subsegments Subsegments [Axis] Contract liabilities (including $39,958 and $40,654 Contract liabilities of consolidated joint ventures) Contract liabilities Contract liabilities Contract with Customer, Liability, Current Loss Contingency, Nature [Domain] 2023 Finite-Lived Intangible Asset, Expected Amortization, Remainder of Fiscal Year Lessee Lease Description [Line Items] Lessee, Lease, Description [Line Items] Investments in unconsolidated joint ventures Payments to Acquire Interest in Joint Venture Credit Facility Credit Facility [Domain] Subsequent Events Subsequent Events [Text Block] Diluted weighted average number of shares outstanding Weighted Average Number of Shares Outstanding, Diluted Adjusted EBITDA attributable to noncontrolling interests Adjusted E B I T D A Attributable To Noncontrolling Interests Adjusted EBITDA attributable to noncontrolling interests. Finite-Lived Intangible Assets, Major Class Name Finite-Lived Intangible Assets, Major Class Name [Domain] Credit Facility Credit Facility [Axis] Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Computer Systems and Equipment Computer Equipment [Member] Revisions estimate Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Measure of Progress Number of business day period Debt Instrument Convertible Business Period Debt instrument convertible business period. Current Fiscal Year End Date Current Fiscal Year End Date Depreciation, Total Depreciation expense Depreciation Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations, Total Beginning of year End of period Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Including Disposal Group and Discontinued Operations Total shares repurchased Stock Repurchased During Period, Shares Other noncurrent assets Other Assets, Noncurrent Total shareholders' equity Beginning balance Ending Balance Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Entity Address, Address Line One Entity Address, Address Line One Debt instrument convertible notes additional paid in capital Debt Instrument Convertible Notes Additional Paid In Capital Debt instrument convertible notes additional paid in capital. Noncontrolling Interest Noncontrolling Interest [Member] Finite-Lived Intangible Assets by Major Class Finite-Lived Intangible Assets by Major Class [Axis] Proceeds from borrowings under credit agreement Proceeds from Lines of Credit Proceeds from Lines of Credit, Total Net distributions from (contributions to) unconsolidated joint ventures Distributions From Contributions To Equity Method Investment Distributions from (contributions to) equity method investment. New Accounting Pronouncements Accounting Standards Update and Change in Accounting Principle [Text Block] Income Tax Expense (Benefit), Total Income tax expense Income Tax Expense (Benefit) Senior Notes Senior Notes [Member] Finance Leases Finance Lease, Liability, to be Paid [Abstract] Income Taxes Income Tax Disclosure [Text Block] Balance Sheet Location Balance Sheet Location [Domain] Remaining unsatisfied performance obligations Revenue, Remaining Performance Obligation, Amount Income Tax Disclosure [Abstract] Change in accounting principle, accounting standards update, adoption date Change in Accounting Principle, Accounting Standards Update, Adoption Date Goodwill deductible for tax purposes Business Acquisition, Goodwill, Expected Tax Deductible Amount Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Axis] Goodwill and Intangible Assets Disclosure [Abstract] Accounts receivable Accounts Receivable, Related Parties, Current 2027 Finance Lease, Liability, to be Paid, Year Four Revenue recognized included contract liability Contract with Customer, Liability, Revenue Recognized Amount paid by relator to acquire vehicles for contractor defendant to perform security services Amount Paid To Acquire Vehicles For Contractor Defendant To Perform Security Services Amount paid to acquire vehicles for contractor defendant to perform security services. Other long-term liabilities Increase (Decrease) in Other Noncurrent Liabilities Operating income Operating Income (Loss) Interest rate Debt Instrument, Interest Rate, Stated Percentage ESOP contribution expense Employee Stock Ownership Plan (ESOP), Compensation Expense Liabilities, Noncurrent, Total Noncurrent liabilities Liabilities, Noncurrent Related Party Related Party [Domain] Additional paid-in capital Additional Paid in Capital, Common Stock Payments to Acquire Businesses, Net of Cash Acquired, Total Payments for acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Weighted Average Remaining Lease Term: Weighted Average Remaining Lease Term [Abstract] Weighted average remaining lease term. Average price paid per share Stock Repurchase Average Price Paid Per Share Stock repurchase average price paid per share. Debt issuance date Debt Instrument, Issuance Date Entity Filer Category Entity Filer Category Schedule Of Equity Method Investments [Line Items] Schedule of Equity Method Investments [Line Items] Change in accounting principle, accounting standards update, early adoption Change in Accounting Principle, Accounting Standards Update, Early Adoption [true false] Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total Property and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Transaction-related costs Transaction Related Costs Transaction related costs. Entity Current Reporting Status Entity Current Reporting Status Foreign Exchange Goodwill, Foreign Currency Translation Gain (Loss) Percentage change in contract liabilities Contract With Customer Liability Cumulative Catchup Adjustment To Revenue Change In Measure Of Progress Percent Contract with customer liability cumulative catchup adjustment to revenue change in measure of progress percent. Lease liabilities: Lease Liabilities [Abstract] Lease liabilities. Business Combinations [Abstract] Finite-Lived Intangible Assets, Net, Ending Balance Finite-Lived Intangible Assets, Net, Beginning Balance Net Carrying Amount Finite-Lived Intangible Assets, Net Summary of Changes in Contract Assets and Contract Liabilities Summary Of Changes In Contract Assets And Contract Liabilities Table [Text Block] Summary of changes in contract assets and contract liabilities. Stockholders' Equity Attributable to Parent, Ending Balance Stockholders' Equity Attributable to Parent, Beginning Balance Total joint venture equity Total Parsons Corporation shareholders' equity Stockholders' Equity Attributable to Parent In Process Research and Development In Process Research and Development [Member] Accumulated Other Comprehensive Income (Loss) AOCI Attributable to Parent [Member] Base Rate Base Rate [Member] Backlog Order or Production Backlog [Member] Entity Tax Identification Number Entity Tax Identification Number Income Statement Location Income Statement Location [Axis] Common stock, $1 par value; authorized 1,000,000,000 shares; 146,243,639 and 146,132,016 shares issued; 42,248,807 and 40,960,845 public shares outstanding; 62,565,812 and 63,742,151 ESOP shares outstanding Common Stock, Value, Issued Retained earnings Retained Earnings (Accumulated Deficit), Total Retained Earnings (Accumulated Deficit) Total Parsons Equity Equity Components [Axis] Acquisition related expenses Business Combination, Acquisition Related Costs Accounting Standards Update Accounting Standards Update [Domain] Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Leases [Abstract] Stock repurchase program commencement date Stock Repurchase Program Commencement Date Stock repurchase program commencement date. Contract with Customer, Liability, Total Contract liabilities Contract with Customer, Liability Customer Relationships Customer Relationships [Member] Disaggregation Of Revenue [Table] Disaggregation of Revenue [Table] Convertible Senior Notes Convertible Debt [Member] Equity Method Investments and Joint Ventures [Abstract] Entity Emerging Growth Company Entity Emerging Growth Company Schedule Of Business Acquisitions By Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Interest Expense, Debt, Total Interest expense Interest Expense, Debt Thereafter Finance Lease Liability Payments Due After Year Four Finance lease liability payments due after year four. Goodwill [Line Items] Goodwill [Line Items] Lease existence of option to extend Lessee Lease Existence Of Option To Extend Lessee lease existence of option to extend. Summary of Accounts Receivable, Net Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Lease option to extend Lessee Lease Option To Extend Lessee lease option to extend. Operating Leases Lessee, Operating Lease, Liability, to be Paid [Abstract] Investment, Name Investment, Name [Axis] Description Of Operations Disclosure [Abstract] Description of operations disclosure. Retirement Benefits [Abstract] Depreciation, Depletion and Amortization, Nonproduction, Total Depreciation and amortization Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Document Transition Report Document Transition Report Prepaid expenses and other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets Weighted Average Discount Rate: Weighted Average Discount Rate [Abstract] Weighted average discount rate. Schedule Of Segment Reporting Information By Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Contingencies Commitments and Contingencies Disclosure [Text Block] Accumulated Other Comprehensive Income (Loss), Net of Tax, Total Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Reimbursable cost incurred Reimbursable Cost Incurred Reimbursable cost incurred. Accounts receivable, net (including $212,924 and $217,419 Accounts receivable of consolidated joint ventures, net) Accounts receivable, net Total accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Adjusted EBITDA attributable to Parsons Corporation Reconciliation From Net Income To Adjusted E B I T D A [Abstract] Reconciliation from net income to adjusted EBITDA. Percentage of convertible senior notes repurchased at cash Percentage Of Convertible Senior Notes Repurchased At Cash Percentage of convertible senior notes repurchased at cash. Amortization of debt issue costs Amortization of Debt Issuance Costs Revision of Prior Period Revision of Prior Period [Domain] Net income attributable to Parsons Corporation Net income attributable to Parsons Corporation Net Income (Loss) Debt Instrument, Periodic Payment, Total Interest payments Debt Instrument, Periodic Payment Threshold trading days Debt Instrument, Convertible, Threshold Trading Days Short-term lease liabilities, operating leases Short-term lease liabilities, operating leases (including $2,992 and $2,552 Short-term lease liabilities, operating leases of consolidated joint ventures) Current Lease term of contract Lessee Lease Term Of Contract Lessee lease term of contract. Contract with Customer, Basis of Pricing Contract with Customer, Basis of Pricing [Axis] Additional Paid-in Capital Additional Paid-in Capital [Member] Decrease in uncertain tax positions during the next twelve months Decrease in Unrecognized Tax Benefits is Reasonably Possible Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Taxes Payable, Current, Total Income taxes payable Taxes Payable, Current Accrued Expenses and Other Current Liabilities Accrued Expenses And Other Current Liabilities [Member] Accrued expenses and other current liabilities. Entity Registrant Name Entity Registrant Name Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Total Foreign currency translation adjustment, net of tax Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Cash and cash equivalents (including $96,662 and $53,193 Cash of consolidated joint ventures) Cash and Cash Equivalents, at Carrying Value, Total Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Earnings Per Share Earnings Per Share [Text Block] Maturity Date Debt Instrument, Maturity Date Lessee Lease Description [Table] Lessee, Lease, Description [Table] Share-Based Payment Arrangement, Noncash Expense, Total Stock-based compensation Share-Based Payment Arrangement, Noncash Expense Statement of Comprehensive Income [Abstract] Property and equipment, net (including $3,083 and $2,543 Property and equipment of consolidated joint ventures, net) Property and equipment, net Property and equipment, net Property, Plant and Equipment, Net Amortization of right-of-use assets Finance Lease, Right-of-Use Asset, Amortization Statement [Line Items] Statement [Line Items] Accounting Standards Update and Change in Accounting Principle [Abstract] Title of 12(b) Security Title of 12(b) Security Finite-Lived Intangible Assets, Gross, Total Gross Carrying Amount Finite-Lived Intangible Assets, Gross Return on investments in unconsolidated joint ventures Proceeds from Equity Method Investment, Distribution Increase (Decrease) in Accounts Payable, Total Accounts payable Increase (Decrease) in Accounts Payable Common Stock Common Stock [Member] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Pro forma Net Income including noncontrolling interests Business Acquisition Pro Forma Net Income Loss Including Portion Attributable To Noncontrolling Interest Business acquisition, pro forma net income (loss), including portion attributable to noncontrolling interest. Equity Component Equity Component [Domain] 2023 (remaining) Finance Lease, Liability, to be Paid, Remainder of Fiscal Year Total revenue Revenues Revenue Income before income tax expense Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Less: imputed interest Finance Lease, Liability, Undiscounted Excess Amount Entity Address, State or Province Entity Address, State or Province 2027 Lessee, Operating Lease, Liability, to be Paid, Year Four Geographical Geographical [Axis] Taxes paid on vested stock Payments For Taxes Paid On Vested Stock Payments for taxes paid on vested stock. Net decrease in cash, cash equivalents, and restricted cash Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Comprehensive income including noncontrolling interests, net of tax Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Document Type Document Type Schedule of Supplemental Pro Forma Information Business Acquisition, Pro Forma Information [Table Text Block] Goodwill Goodwill Disclosure [Text Block] United States UNITED STATES Schedule of Supplemental Balance Sheet and Other Information Related to Leases Schedule Of Balance Sheet Information Related To Leases Table [Text Block] Schedule of balance sheet information related to leases. Entity Shell Company Entity Shell Company Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] BlackHorse Solutions, Inc. Black Horse Solutions Inc [Member] BlackHorse Solutions, Inc. North America North America [Member] Shareholders' equity: Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Security Exchange Name Security Exchange Name Revenue from Contract with Customer [Abstract] Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Other long-term liabilities Finance Lease, Liability, Noncurrent Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Additional deferred tax liability related to capitalized debt issuance costs Additional Deferred Tax Liability Related To Capitalized Debt Issuance Cost Additional deferred tax liability related to Capitalized debt issuance cost. Convertible senior notes effective interest rate Debt Instrument, Interest Rate, Effective Percentage Other comprehensive income, net of tax Other Comprehensive Income (Loss), Net of Tax [Abstract] Schedule Of Employee Stock Ownership Plan E S O P Disclosures [Table] Schedule of Employee Stock Ownership Plan (ESOP) Disclosures [Table] Cash paid to acquire Payments to Acquire Businesses, Gross Commitments and Contingencies Disclosure [Abstract] Operating lease cost Operating Lease, Cost Interest payable Interest Payable, Current 2025 Finance Lease, Liability, to be Paid, Year Two Employee Stock Ownership Plan (ESOP), Shares in ESOP, Total Company's stock held by ESOP Employee Stock Ownership Plan (ESOP), Shares in ESOP Pro forma Revenue Business Acquisition, Pro Forma Revenue New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Total Finite Lived Intangible Assets Amortizable Amount Finite lived intangible assets amortizable amount. Common Stock, Shares, Outstanding, Ending Balance Common Stock, Shares, Outstanding, Beginning Balance Common stock, shares, outstanding Common Stock, Shares, Outstanding Business Acquisition [Line Items] Business Acquisition [Line Items] Accounts receivable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Debt and Credit Facilities Debt Disclosure [Text Block] Level 2 Fair Value, Inputs, Level 2 [Member] Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Schedule of Estimated Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Accrued expenses and other current liabilities Increase Decrease In Accrued Expenses And Other Current Liabilities Increase (decrease) in accrued expenses and other current liabilities. Contingencies (Note 12) Commitments and Contingencies Employee Stock Ownership Plan (ESOP) Disclosures [Line Items] Employee Stock Ownership Plan (ESOP) Disclosures [Line Items] Net assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Common stock, shares, issued Common Stock, Shares, Issued Reclassification of equity component of debt issuance costs to liabilities Reclassification Of Equity Component Of Debt Issuance Costs To Liabilities Reclassification of equity component of debt issuance costs to liabilities. Convertible principal amount Debt Instrument Convertible Principal Amount Debt instrument convertible principal amount. Variable Rate Variable Rate [Domain] Minimum Minimum [Member] Minimum [Member] Debt instrument, frequency of periodic payment Debt Instrument, Frequency of Periodic Payment Shares fully vested, Description Share-Based Compensation Arrangement by Share-Based Payment Award, Description Contributions Minority Interest Increase Decrease From Contributions To Noncontrolling Interest Holders Minority interest increase (decrease) from contributions to noncontrolling interest holders. Senior Note, Series A Series A Senior Note [Member] Series A senior note. Percentage of principal amount to redeem convertible senior notes Percentage Of Principal Amount To Redeem Convertible Senior Notes Percentage of principal amount to redeem convertible senior notes. Segments Segments [Domain] Proceeds from issuance and sale of debt Proceeds from Debt, Net of Issuance Costs Leases Lessee, Leases [Policy Text Block] Repayments of borrowings under credit agreement Repayments of borrowings under credit agreement Repayments of Lines of Credit Accounting Standards Update Accounting Standards Update [Axis] Acquired contract assets Contract with Customer, Asset, Increase (Decrease) for Contract Acquired in Business Combination Impairment of contract assets Capitalized Contract Cost, Impairment Loss Debt Instrument [Axis] Treasury Stock Treasury Stock [Member] Foreign Currency Transaction Gain (Loss), before Tax, Total Foreign currency transaction gains and losses Foreign Currency Transaction Gain (Loss), before Tax Other Intangibles Other Intangible Assets [Member] Segments Segments [Axis] Purchase of bond hedges and sale of warrants Net Cost Of Purchase Of Bond Hedges And Sale Of Warrants Net cost of purchase of bond hedges and sale of warrants. Cost-Plus Cost Plus [Member] Cost plus. Amortization expense of intangible assets Amortization of intangible assets Amortization of Intangible Assets Subsequent Event Subsequent Event [Member] Euro Currency Rate Eurodollar [Member] Other Nonoperating Income (Expense), Total Other income (expense), net Other Nonoperating Income (Expense) Reclassification of equity component of convertible senior notes to liabilities Reclassification Of Equity Component Of Convertible Senior Notes To Liabilities Reclassification of equity component of convertible senior notes to liabilities. Schedule of Repurchase Program Class of Treasury Stock [Table Text Block] Total lease payments Lessee, Operating Lease, Liability, to be Paid Fixed-Price Fixed-Price Contract [Member] Contract retentions, not expected to be paid in next 12 months Contract Receivable Retainage Asset Liabilities Net Due After One Year Contract receivable retainage asset (liabilities) net, due after one year. Entity Central Index Key Entity Central Index Key Right-of-use assets obtained in exchange for new finance lease liabilities Right-of-Use Asset Obtained in Exchange for Finance Lease Liability Restructuring expense Restructuring Income Expense Restructuring income (expense). Accounting Policies [Abstract] Measurement period, percentage Debt Instrument Convertible Measurement Period Percentage Debt instrument convertible measurement period percentage. Time-and-Materials Time-and-Materials Contract [Member] Disaggregation Of Revenue [Line Items] Disaggregation of Revenue [Line Items] Construction Equipment Construction Equipment [Member] Construction equipment. Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Ending Balance Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Beginning Balance Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment, Total Accumulated depreciation Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Schedule Of Property Plant And Equipment [Table] Property, Plant and Equipment [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Finance leases Finance Lease, Weighted Average Discount Rate, Percent Transaction fees and other third-party offering expenses Debt Instrument, Fee Amount Subsequent Event [Table] Subsequent Event [Table] Summary of Revenues and Property and Equipment, Net by Geographic Area Summary Of Revenues And Property And Equipment Net By Geographic Area Table [Text Block] Summary of revenues and property and equipment, net by geographic area. Organization, Consolidation and Presentation of Financial Statements [Abstract] Schedule Of Equity Method Investments [Table] Schedule of Equity Method Investments [Table] Financing cash flows from finance leases Finance Lease, Principal Payments Debt Issuance Costs, Net, Total Debt issuance costs incurred Debt Issuance Costs, Net Total lease cost Lease, Cost Debt Instrument, conversion price Debt Instrument, Convertible, Conversion Price Right-of-use assets obtained in exchange for new operating lease liabilities Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Equity Method Investment, Nonconsolidated Investee [Domain] Stock Repurchase Plan Stock Repurchase Plan Policy [Text Block] Stock repurchase plan. Adjustments to reconcile net income to net cash used in operating activities Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Retained Earnings (Accumulated Deficit) Retained Earnings [Member] Equity in losses (earnings) of unconsolidated joint ventures Equity in (losses) earnings of unconsolidated joint ventures Equity in earnings of unconsolidated joint ventures Income (Loss) from Equity Method Investments Net contract assets (liabilities) Contract With Customer Asset Liability Net Contract with customer asset and liabilities net. Segment Reporting [Abstract] Effective Income Tax Rate Reconciliation, Percent, Total Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Gain on disposal of property and equipment Gain (Loss) on Disposition of Property Plant Equipment, Total Gain (Loss) on Disposition of Property Plant Equipment Schedule Of Goodwill [Table] Schedule of Goodwill [Table] SOFR Benchmark Rate Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member] Property, Plant and Equipment, Gross, Ending Balance Property, Plant and Equipment, Gross, Beginning Balance Property, Plant and Equipment, Gross, Total Property and equipment, gross Property, Plant and Equipment, Gross Acquisitions Goodwill, Acquired During Period Gross Carrying Amount Finite-Lived Intangible Assets Acquired Entity Interactive Data Current Entity Interactive Data Current Threshold consecutive trading days Debt Instrument, Convertible, Threshold Consecutive Trading Days Debt Issuance Costs, Noncurrent, Net, Total Long-term debt issuance costs Debt Issuance Costs, Noncurrent, Net Related Party Transactions Related Party Transactions Disclosure [Text Block] Letters of credit outstanding amount Letters of Credit Outstanding, Amount Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill, Total Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Bond hedge term Bond Hedge Term Bond hedge term. Deferred tax liability reversed Reversal Of Deferred Tax Liability Reversal of deferred tax liability. Payments for acquired warrants Payments for acquired warrants Payments for Repurchase of Warrants Related Party Transactions [Abstract] Middle East Middle East [Member] Adjusted EBITDA attributable to Parsons Corporation Adjusted E B I T D A Attributable To Parent Adjusted EBITDA attributable to parent. 2024 Lessee, Operating Lease, Liability, to be Paid, Year One Legal Proceedings [Line Items] Legal Proceedings. Thereafter Lessee Operating Lease Liability Payments Due After Year Four Lessee operating lease liability payments due after year four. Provision for doubtful accounts Accounts Receivable, Credit Loss Expense (Reversal) Federal Solutions Federal Solution Segment Federal Solution Segment [Member] Federal Solution Segment. Number of claims outstanding Loss Contingency Number Of Claims Loss contingency, number of claims. Proceeds from issuance of warrants Cash proceeds from sales of warrants Proceeds from Issuance of Warrants Local Phone Number Local Phone Number U.S. corporate tax rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Preliminary Purchase Price Allocation Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Percentage change in contract assets Contract With Customer Asset Cumulative Catchup Adjustment To Revenue Change In Measure Of Progress Percent Contract with customer asset cumulative catchup adjustment to revenue change in measure of progress percent. Shares fully vested after credited service Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period Debt Disclosure [Abstract] Net Income (Loss) Attributable to Noncontrolling Interest, Total Net income attributable to noncontrolling interests Net income attributable to noncontrolling interests Net income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Operating lease not yet commenced expense Operating Lease Not Yet Commenced Expense Operating lease not yet commenced expense. Basis of Presentation and Principles of Consolidation Basis of Accounting, Policy [Policy Text Block] Summary of Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Other long-term liabilities Other Liabilities, Noncurrent Debt instrument, payment terms Debt Instrument, Payment Terms Income Statement Location Income Statement Location [Domain] Xator Corporation Xator Corporation [Member] Xator corporation member. Change in contract assets and liabilities Change In Contract With Customer Assets And Liabilities Net Change in contract with customer assets and liabilities net. Echo Ridge LLC Echo Ridge L L C [Member] Echo Ridge LLC. Number of shares issuable upon conversion Debt Instrument Number Of Shares Issuable Upon Conversion Debt instrument number of shares issuable upon conversion. Selling, General and Administrative Expense Selling, General and Administrative Expenses [Member] Property, Plant and Equipment [Abstract] Assets, Noncurrent, Total Noncurrent assets Assets, Noncurrent Accrued expenses and other current liabilities (including $128,145 and $102,417 Accrued expenses and other current liabilities of consolidated joint ventures) Accrued expenses and other current liabilities Accrued Expenses And Other Current Liabilities Accrued expenses and other current liabilities. Total Long-Term Debt Prepaid expenses and other assets Increase (Decrease) in Prepaid Expense and Other Assets Cost of convertible note hedge transaction Cost Of Convertible Note Hedge Transaction Cost of convertible note hedge transactions. Debt Instrument, Name [Domain] Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures, Total Investments in and advances to unconsolidated joint ventures Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures Document Fiscal Year Focus Document Fiscal Year Focus Intangible Assets, Net (Excluding Goodwill), Total Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Senior note, amount paid Repayments of Debt Payments for debt costs and credit agreement Payments of Debt Issuance Costs, Total Payments for debt costs and credit agreement Payments of Debt Issuance Costs Loss contingency sought value, civil penalty for each alleged violation of Act Loss Contingency Sought Value Civil Penalty For Each Alleged Violation Of Act Loss contingency sought value, civil penalty for each alleged violation of Act. Consolidated Joint Ventures Consolidated Joint Ventures [Member] Consolidated joint ventures. 2025 Lessee, Operating Lease, Liability, to be Paid, Year Two Earnings Per Share, Basic, Total Basic Earnings Per Share, Basic Retirement Benefit Plan Compensation and Employee Benefit Plans [Text Block] Assets Assets [Abstract] Contributions by noncontrolling interests Proceeds from Noncontrolling Interests Prepaid expenses and other current assets (including $12,871 and $7,913 Prepaid expenses and other current assets of consolidated joint ventures) Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Credit agreement maturity period Line of Credit Facility, Expiration Period Treasury stock, 41,429,020 shares at cost Treasury Stock, Value, Total Treasury Stock, Value Debt amount Debt Amount Debt Instrument, Face Amount Equity-based Awards Stock-based Awards Share-Based Payment Arrangement [Member] Long-Lived Tangible Asset Long-Lived Tangible Asset [Axis] Percentage of ownership interest acquired Business Acquisition, Percentage of Voting Interests Acquired Liabilities and Shareholders' Equity Liabilities and Equity [Abstract] Antidilutive Securities, Name Antidilutive Securities, Name [Domain] Developed Technologies Developed Technology Developed Technology Rights [Member] Net income Net income including noncontrolling interests Net income including noncontrolling interests Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Joint Ventures Joint Ventures [Member] Joint ventures. Current assets: Assets, Current [Abstract] 2027 Finite-Lived Intangible Asset, Expected Amortization, Year Four 2025 Finite-Lived Intangible Asset, Expected Amortization, Year Two Exercise price of warrants Class of Warrant or Right, Exercise Price of Warrants or Rights Segment Information Segment Reporting Disclosure [Text Block] Critical Infrastructure Critical Infrastructure Segment [Member] Critical Infrastructure Segment. 2022 Delayed Draw Term Loan Two Thousand Twenty Two Delayed Draw Term Loan [Member] Two Thousand Twenty Two Delayed Draw Term Loan [Member] Decrease in net income net of tax Decrease in net income net of tax. Thereafter Finite Lived Intangible Assets Amortization Expense After Year Four Finite lived intangible assets amortization expense after year four. Summary of Changes in Carrying Value of Goodwill by Reporting Segment Schedule of Goodwill [Table Text Block] Fair Value Hierarchy and NAV Fair Value Hierarchy and NAV [Domain] Operating Leases: Operating Leases [Abstract] Operating lease. Changes in assets and liabilities, net of acquisitions and newly consolidated joint ventures: Increase (Decrease) in Operating Capital [Abstract] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Debt liability Debt Instrument Convertible Debt Liability Debt instrument convertible debt liability. Cover [Abstract] Weighted Average Amortization Period (in years) Amortization Period (in years) Acquired Finite-Lived Intangible Assets, Weighted Average Useful Life Impairment of goodwill Goodwill, Impairment Loss Acquired Finite Lived Intangible Assets [Line Items] Acquired Finite-Lived Intangible Assets [Line Items] Schedule of Consolidated Balance Sheet Related to Services Provided to Unconsolidated Joint Ventures Schedule Of Consolidated Balance Sheet Related To Unconsolidated Joint Ventures Table [Text Block] Schedule of consolidated balance sheet related to unconsolidated joint ventures. Current liabilities: Liabilities, Current [Abstract] Noncompete Agreements Noncompete Agreements [Member] Maximum Maximum [Member] Repayment of private placement debt Repayment of private placement debt Repayment Of Private Placement Debt Repayment of private placement Debt. Number of common stock acquired by offsetting sale warrants. Number Of Common Stock Acquired By Offsetting Sale Warrants Number of common stock acquired by offsetting sale warrants. Cash, cash equivalents and restricted cash: Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect [Abstract] Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Furniture and Equipment Furniture and Fixtures [Member] Convertible notes converted each into shares of common stock Convertible Notes Converted Each Into Shares Of Common Stock Convertible notes converted each into shares of common stock. Finance Leases: Finance Leases [Abstract] Finance leases. Schedule Of Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Total other income (expense) Other Income Expense Other income (expense). Use of Estimates Use of Estimates, Policy [Policy Text Block] Margin interest rate Debt Instrument, Basis Spread on Variable Rate Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration] Credit agreement number of extensions Line Of Credit Facility Number Of Extensions Line of credit facility number of extensions. Repurchases of common stock Adjustments To Additional Paid In Capital Repurchases Of Common Stock Adjustments to additional paid in capital repurchases of common stock. Useful life (years) Property, Plant and Equipment, Useful Life Stock repurchase program, remaining authorized repurchase amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Debt instrument, outstanding amount Long-term debt Long-Term Debt, Gross 2026 Finite-Lived Intangible Asset, Expected Amortization, Year Three Common stock, shares authorized Common Stock, Shares Authorized Trading Symbol Trading Symbol Total Parsons Equity Parent [Member] Selling, General and Administrative Expense, Total Selling, general and administrative expenses Selling, General and Administrative Expense Subsequent Event Type Subsequent Event Type [Axis] Senior notes, fair value Notes Payable, Fair Value Disclosure Balance Sheet Location Balance Sheet Location [Axis] Comprehensive income attributable to Parsons Corporation, net of tax Comprehensive Income (Loss), Net of Tax, Attributable to Parent Proceeds from Sale of Property, Plant, and Equipment, Total Proceeds from sale of property and equipment Proceeds from Sale of Property, Plant, and Equipment Accounts payable (including $45,581 and $49,078 Accounts payable of consolidated joint ventures) Accounts Payable, Current, Total Accounts payable Accounts Payable, Current Plan Name Plan Name [Axis] Schedule Of Related Party Transactions By Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] ESOP Employee Stock Ownership Plan [Member] Employee Stock Ownership Plan. Long-Lived Tangible Asset Long-Lived Tangible Asset [Domain] Distributions Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Proceeds from delayed draw term loan Proceeds from Issuance of Unsecured Debt Debt instrument, maturity period Debt Instrument, Term Equity Method Investment, Nonconsolidated Investee [Axis] Common stock, par value Common Stock, Par or Stated Value Per Share Summary of Revenues by Business Lines Revenue from External Customers by Products and Services [Table Text Block] Other noncurrent assets Finance Leases Other Assets Noncurrent Finance leases other assets noncurrent. Authorized shares of common stock value Stock Repurchase Program, Authorized Amount Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration] Credit agreement date Line of Credit Facility, Initiation Date Revenue, remaining performance obligation, expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Property and Equipment, Net Property, Plant and Equipment Disclosure [Text Block] Schedule of Financial Information of Consolidated Joint Ventures Schedule Of Financial Information Of Consolidated Joint Ventures Table [Text Block] Schedule of financial information of consolidated joint ventures. Other noncurrent assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Other Other Reconciliation From Net Income To Adjusted E B I T D A Other reconciliation from net income to adjusted EBITDA. Debt Instrument [Line Items] Debt Instrument [Line Items] Long-term Debt, Type Long-Term Debt, Type [Domain] Antidilutive securities excluded from computation of earnings per share Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Summary of Adjusted EBITDA Business Segment Information Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]