Parsons (PSN) 10-K 19 Feb 25 2024 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2024	Feb. 11, 2025	Jun. 30, 2024
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2024
Document Fiscal Year Focus	2024
Document Fiscal Period Focus	FY
Entity Registrant Name	PARSONS CORPORATION
Entity Central Index Key	0000275880
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		106,777,126
Entity Public Float			$ 8.7
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
Entity File Number	001-07782
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	95-3232481
Entity Address, Address Line One	14291 Park Meadow Drive
Entity Address, Address Line Two	Suite 100
Entity Address, City or Town	Chantilly
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	20151
City Area Code	703
Local Phone Number	988-8500
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	true
Document Financial Statement Error Correction Flag	false
Title of each class	Common Stock, $1 par value
Trading Symbol(s)	PSN
Name of each exchange on which registered	NYSE
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Los Angeles, California
Auditor Firm ID	238
Auditor Opinion	Opinions on the Financial Statements and Internal Control over Financial Reporting We have audited the accompanying consolidated balance sheets of Parsons Corporation and its subsidiaries (the “Company”) as of December 31, 2024 and 2023, and the related consolidated statements of income, of comprehensive income, of changes in shareholders’ equity and of cash flows for each of the three years in the period ended December 31, 2024, including the related notes and schedule of valuation and qualifying accounts for each of the three years in the period ended December 31, 2024 appearing under Item 15(a)(2) (collectively referred to as the “consolidated financial statements”). We also have audited the Company's internal control over financial reporting as of December 31, 2024 based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the three years in the period ended December 31, 2024 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO.
Documents Incorporated by Reference	Portions of Parsons’ 2025 Proxy Statement are incorporated by reference into Part III of this Annual Report on Form 10-K.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Current assets:
Cash and cash equivalents (including $202,121 and $128,761 Cash of consolidated joint ventures)	$ 453,548	$ 272,943
Accounts receivable, net (including $294,700 and $274,846 Accounts receivable of consolidated joint ventures, net)	1,100,396	915,638
Contract assets (including $7,906 and $11,096 Contract assets of consolidated joint ventures)	741,504	757,515
Prepaid expenses and other current assets (including $14,723 and $11,929 Prepaid expenses and other current assets of consolidated joint ventures)	166,952	191,430
Total current assets	2,462,400	2,137,526
Property and equipment, net (including $2,971 and $3,274 Property and equipment of consolidated joint ventures, net)	111,575	98,957
Right of use assets, operating leases (including $5,726 and $9,885 Right of use assets, operating leases of consolidated joint ventures)	153,048	159,211
Goodwill	2,082,680	1,792,665
Investments in and advances to unconsolidated joint ventures	138,759	128,204
Intangible assets, net	349,937	275,566
Deferred tax assets	133,450	140,162
Other noncurrent assets	56,113	71,770
Total assets	5,487,962	4,804,061
Current liabilities:
Accounts payable (including $28,214 and $49,234 Accounts payable of consolidated joint ventures)	207,589	242,821
Accrued expenses and other current liabilities (including $198,797 and $145,040 Accrued expenses and other current liabilities of consolidated joint ventures)	894,425	801,423
Contract liabilities (including $66,144 and $61,234 Contract liabilities of consolidated joint ventures)	289,799	301,107
Short-term lease liabilities, operating leases (including $3,522 and $4,753 Short-term lease liabilities, operating leases of consolidated joint ventures)	52,725	58,556
Income taxes payable	7,701	6,977
Short-term debt	463,405	0
Total current liabilities	1,915,644	1,410,884
Long-term employee incentives	31,818	22,924
Long-term debt	784,096	745,963
Long-term lease liabilities, operating leases (including $2,203 and $5,132 Long-term lease liabilities, operating leases of consolidated joint ventures)	114,386	117,505
Deferred tax liabilities	11,043	9,775
Other long-term liabilities	96,486	120,295
Total liabilities	2,953,473	2,427,346
Contingencies
Shareholders' equity:
Common stock, $1 par value; authorized 1,000,000,000 shares; 146,656,225 and 146,341,363 shares issued; 52,657,447 and 45,960,122 public shares outstanding; 54,117,904 and 59,879,857 ESOP shares outstanding	146,655	146,341
Treasury stock, 39,880,875 shares at cost	(815,282)	(827,311)
Additional paid-in capital	2,684,829	2,779,365
Retained earnings	426,781	203,724
Accumulated other comprehensive loss	(26,594)	(14,908)
Total Parsons Corporation shareholders' equity	2,416,389	2,287,211
Noncontrolling interests	118,100	89,504
Total shareholders' equity	2,534,489	2,376,715
Total liabilities and shareholders' equity	$ 5,487,962	$ 4,804,061

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Cash and cash equivalents	$ 453,548	$ 272,943
Accounts receivable, net	1,100,396	915,638
Contract assets	741,504	757,515
Prepaid expenses and other current assets	166,952	191,430
Property and equipment, net	111,575	98,957
Right of use assets, operating leases	153,048	159,211
Accounts payable	207,589	242,821
Accrued expenses and other current liabilities	$ 894,425	$ 801,423
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares, issued	146,656,225	146,341,363
Common stock, shares, outstanding	52,657,447	45,960,122
Treasury stock, shares	39,880,875	39,880,875
Contract liabilities	$ 289,799	$ 301,107
Short-term lease liabilities, operating leases	52,725	58,556
Long-term lease liabilities, operating leases	$ 114,386	$ 117,505
ESOP
Common stock, shares, outstanding	54,117,904	59,879,857
Consolidated Joint Ventures
Cash and cash equivalents	$ 202,121	$ 128,761
Accounts receivable, net	294,700	274,846
Contract assets	7,906	11,096
Prepaid expenses and other current assets	14,723	11,929
Property and equipment, net	2,971	3,274
Right of use assets, operating leases	5,726	9,885
Accounts payable	28,214	49,234
Accrued expenses and other current liabilities	198,797	145,040
Contract liabilities	66,144	61,234
Short-term lease liabilities, operating leases	3,522	4,753
Long-term lease liabilities, operating leases	$ 2,203	$ 5,132

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenue	$ 6,750,576	$ 5,442,749	$ 4,195,272
Direct cost of contracts	5,344,154	4,236,735	3,248,550
Equity in (losses) earnings of unconsolidated joint ventures	(23,361)	(47,751)	16,347
Selling, general and administrative expenses	954,995	869,905	777,403
Operating income	428,066	288,358	185,666
Interest income	11,428	2,191	966
Interest expense	(51,582)	(31,497)	(23,185)
Convertible debt repurchase loss	(18,355)	0	0
Other income (expense), net	(1,906)	5,001	2,775
Total other (expense) income	(60,415)	(24,305)	(19,444)
Income before income tax expense	367,651	264,053	166,222
Income tax expense	(76,986)	(56,138)	(39,657)
Net income including noncontrolling interests	290,665	207,915	126,565
Net income attributable to noncontrolling interests	(55,612)	(46,766)	(29,901)
Net income attributable to Parsons Corporation	$ 235,053	$ 161,149	$ 96,664
Earnings per share:
Basic earnings per share	$ 2.21	$ 1.53	$ 0.93
Diluted earnings per share	$ 2.12	$ 1.42	$ 0.87

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Statement of Comprehensive Income [Abstract]
Net income including noncontrolling interests	$ 290,665	$ 207,915	$ 126,565
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment, net of tax	(11,546)	2,375	(7,752)
Pension adjustments, net of tax	(131)	568	(547)
Comprehensive income including noncontrolling interests, net of tax	278,988	210,858	118,266
Comprehensive income attributable to noncontrolling interests, net of tax	(55,621)	(46,768)	(29,883)
Comprehensive income attributable to Parsons Corporation, net of tax	$ 223,367	$ 164,090	$ 88,383

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive (Loss) Income	Total Parsons Equity	Noncontrolling Interests
Beginning balance at Dec. 31, 2021	$ 1,937,112	$ 146,277	$ (867,391)	$ 2,684,979	$ (53,529)	$ (9,568)	$ 1,900,768	$ 36,344
Comprehensive income
Net income	126,565				96,664		96,664	29,901
Foreign currency translation gain (loss), net	(7,752)					(7,734)	(7,734)	(18)
Pension adjustments, net	(547)					(547)	(547)
Contributions of treasury stock to ESOP	53,801		22,455	31,346			53,801
Contributions	10,266							10,266
Distributions	(24,128)							(24,128)
Issuance of equity securities, net of retirements	(390)	429		(773)	(46)		(390)
Repurchases of common stock	(22,000)	(574)		(21,426)			(22,000)
Stock-based compensation	23,008			23,008			23,008
Ending Balance at Dec. 31, 2022	2,095,935	146,132	(844,936)	2,717,134	43,089	(17,849)	2,043,570	52,365
Comprehensive income
Net income	207,915				161,149		161,149	46,766
Foreign currency translation gain (loss), net	2,375					2,373	2,373	2
Pension adjustments, net	568					568	568
Contributions of treasury stock to ESOP	57,429		17,625	39,804			57,429
Contributions	2,867							2,867
Distributions	(12,496)							(12,496)
Issuance of equity securities, net of retirements	(1,243)	442		(1,171)	(514)		(1,243)
Repurchases of common stock	(11,000)	(233)		(10,767)			(11,000)
Stock-based compensation	34,365			34,365			34,365
Ending Balance at Dec. 31, 2023	2,376,715	146,341	(827,311)	2,779,365	203,724	(14,908)	2,287,211	89,504
Comprehensive income
Net income	290,665				235,053		235,053	55,612
Foreign currency translation gain (loss), net	(11,546)					(11,555)	(11,555)	9
Pension adjustments, net	(131)					(131)	(131)
Contributions of treasury stock to ESOP	58,228		12,029	46,199			58,228
Contributions	2,174							2,174
Distributions	(29,199)							(29,199)
Capped call transactions	(66,121)			(66,121)			(66,121)
Repurchase of warrants	(104,952)			(104,952)			(104,952)
Bond hedge termination	149,308			149,308			149,308
Issuance of equity securities, net of retirements	(14,630)	601		(3,235)	(11,996)		(14,630)
Convertible debt inducement	(147,105)			(147,105)			(147,105)
Repurchases of common stock	(24,999)	(287)		(24,712)			(24,999)
Stock-based compensation	56,082			56,082			56,082
Ending Balance at Dec. 31, 2024	$ 2,534,489	$ 146,655	$ (815,282)	$ 2,684,829	$ 426,781	$ (26,594)	$ 2,416,389	$ 118,100

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flows from operating activities
Net income including noncontrolling interests	$ 290,665	$ 207,915	$ 126,565
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	99,251	119,973	120,501
Amortization of debt issue costs	7,799	2,842	3,029
Loss (gain) on disposal of property and equipment	948	206	(164)
Convertible debt repurchase loss	18,355	0	0
Provision for doubtful accounts	0	32	57
Deferred taxes	6,101	(8,914)	(844)
Foreign currency transaction gains and losses	6,919	(330)	1,973
Equity in losses (earnings) of unconsolidated joint ventures	23,361	47,751	(16,347)
Return on investments in unconsolidated joint ventures	40,162	48,970	28,417
Stock-based compensation	56,082	34,365	23,008
Contributions of treasury stock	59,778	58,172	54,659
Changes in assets and liabilities, net of acquisitions and newly consolidated joint ventures
Accounts receivable	(163,139)	(176,181)	(117,318)
Contract assets	31,881	(119,898)	(32,032)
Prepaid expenses and other assets	35,830	(95,415)	(1,405)
Accounts payable	(42,686)	24,497	(717)
Accrued expenses and other current liabilities	79,984	163,440	3,879
Contract liabilities	(11,325)	84,439	41,306
Income taxes	(341)	2,886	(3,649)
Other long-term liabilities	(16,019)	12,949	6,608
Net cash provided by operating activities	523,606	407,699	237,526
Cash flows from investing activities
Capital expenditures	(49,213)	(40,396)	(30,593)
Proceeds from sale of property and equipment	179	546	771
Payments for acquisitions, net of cash acquired	(428,710)	(221,937)	(379,467)
Investments in unconsolidated joint ventures	(133,921)	(119,582)	(17,622)
Return of investments in unconsolidated joint ventures	54,950	5,018	9,443
Proceeds from sales of investments in unconsolidated joint ventures	0	381	0
Net cash used in investing activities	(556,715)	(375,970)	(417,468)
Cash flows from financing activities
Proceeds from borrowings under credit agreement	153,200	620,900	969,700
Proceeds from delayed draw term loan	0	0	350,000
Repayments of borrowings under credit agreement	(153,200)	(620,900)	(969,700)
Repayment of private placement debt	0	0	(200,000)
Payments for acquired warrants	0	0	(11,243)
Proceeds from issuance of convertible notes due 2029	800,000	0	0
Repurchases of convertible notes due 2025	(497,613)	0	0
Payments for debt costs and credit agreement	(19,185)	0	(862)
Contributions by noncontrolling interests	2,174	2,867	10,266
Distributions to noncontrolling interests	(29,199)	(12,496)	(24,128)
Repurchases of common stock	(25,000)	(11,000)	(22,000)
Taxes paid on vested stock	(22,560)	(7,301)	(7,042)
Capped call transactions	(88,400)	0	0
Bond hedge termination	195,549	0	0
Redemption of warrants	(104,952)	0	0
Proceeds from issuance of common stock	7,935	6,059	5,377
Net cash provided by (used in) financing activities	218,749	(21,871)	100,368
Effect of exchange rate changes	(5,035)	546	(1,770)
Net increase (decrease) in cash, cash equivalents and restricted cash	180,605	10,404	(81,344)
Cash, cash equivalents and restricted cash
Beginning of year	272,943	262,539	343,883
End of year	453,548	272,943	262,539
Cash paid during the year for
Interest	34,440	30,273	20,819
Income taxes (net of refunds)	$ 65,274	$ 74,133	$ 32,175

Cybersecurity Risk Management,

Cybersecurity Risk Management, Strategy and Governance	12 Months Ended
	Dec. 31, 2024
Cybersecurity Risk Management, Strategy, and Governance [Line Items]
Cybersecurity Risk Management Processes for Assessing, Identifying, and Managing Threats [Text Block]	Item 1C. Cybersecurity. We have developed and implemented a cybersecurity risk management program intended to protect the confidentiality, integrity, and availability of our critical systems and information. Our cybersecurity risk management program includes a cybersecurity incident response plan. We use NIST Cybersecurity Framework and CIS Critical Security Controls as a guide to help us identify, assess, and manage cybersecurity relevant to our business. We are also structured to CMMC which aligns with DOD/Federal contractor program compliance. This does not imply that we meet any particular technical standards, specifications, or requirements. Our cybersecurity risk management program is integrated with our overall enterprise risk management program, and shares common methodologies, reporting channels and governance processes that apply across the enterprise risk management program to other legal, compliance, strategic, operational, and financial risk areas. Our cybersecurity risk management program includes the following key elements: • risk assessments designed to help identify material cybersecurity risks to our critical systems, information, services, and our broader enterprise IT environment; • a team comprised of IT security, IT infrastructure, and IT compliance personnel principally responsible for directing (1) our cybersecurity risk assessment processes; (2) our security processes; and (3) our response to cybersecurity incidents; • the use of external cybersecurity service providers, where appropriate, to assess, test or otherwise assist with aspects of our security processes ; • cybersecurity awareness training of employees with access to our IT systems; • a cybersecurity incident response plan and Security Operations Center to respond to cybersecurity incidents; • a third-party risk management process for service providers. We have not identified risks from known cybersecurity threats, including as a result of any prior cybersecurity incidents, that have materially affected us, including our operations, business strategy, results of operations, or financial condition. We face certain ongoing risks from cybersecurity threats that, if realized, are reasonably likely to materially affect us , including our operations, business strategy, results of operations, or financial conditions, as we have described in the Risk Factors section of this Form 10-K. Cybersecurity Governance Our Board considers cybersecurity risk as critical to the enterprise and delegates the cybersecurity risk oversight function to the Audit and Risk Committee. The Audit and Risk Committee oversees management’s design, implementation, and enforcement of our cybersecurity risk management program. Our Chief Security & Risk Officer reports to the Chief Technology Officer and works closely with the Chief Legal Officer to ensure that all disclosure or reporting requirements are satisfied if an incident were to occur. The Chief Security & Risk Officer leads Parsons’ overall cybersecurity function and provides quarterly reports to the Audit and Risk Committee on our cybersecurity risks, including briefings on our cybersecurity risk management program and cybersecurity incidents. The Audit and Risk Committee also receives periodic presentations on relevant cybersecurity topics as part of the Committee and the Board’s continuing education on topics that impact public companies. Our Chief Security & Risk Officer supervises efforts to prevent, detect, mitigation and remediate cybersecurity risks and incidents through various means, which include briefings from internal security personnel; threat intelligence and other information obtained from governmental, public or private sources, including external cybersecurity service providers; and alerts and reports produced by security tools deployed in the IT environment. Our Chief Security & Risk Officer is responsible for assessing and managing our material risks from cybersecurity threats and has primary responsibility for leading our overall cybersecurity risks management program and supervises both our internal cybersecurity personnel and our external cybersecurity service providers. Our Chief Security & Risk Officer has significant global experience in managing and leading IT and cybersecurity teams.
Cybersecurity Risk Management Processes Integrated [Flag]	true
Cybersecurity Risk Management Processes Integrated [Text Block]	Our cybersecurity risk management program is integrated with our overall enterprise risk management program, and shares common methodologies, reporting channels and governance processes that apply across the enterprise risk management program to other legal, compliance, strategic, operational, and financial risk areas.
Cybersecurity Risk Management Third Party Engaged [Flag]	true
Cybersecurity Risk Third Party Oversight and Identification Processes [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Flag]	true
Cybersecurity Risk Materially Affected or Reasonably Likely to Materially Affect Registrant [Text Block]	We face certain ongoing risks from cybersecurity threats that, if realized, are reasonably likely to materially affect us , including our operations, business strategy, results of operations, or financial conditions, as we have described in the Risk Factors section of this Form 10-K.
Cybersecurity Risk Board of Directors Oversight [Text Block]	Our Board considers cybersecurity risk as critical to the enterprise and delegates the cybersecurity risk oversight function to the Audit and Risk Committee. The Audit and Risk Committee oversees management’s design, implementation, and enforcement of our cybersecurity risk management program.
Cybersecurity Risk Board Committee or Subcommittee Responsible for Oversight [Text Block]	The Audit and Risk Committee oversees management’s design, implementation, and enforcement of our cybersecurity risk management program.
Cybersecurity Risk Process for Informing Board Committee or Subcommittee Responsible for Oversight [Text Block]	Our Chief Security & Risk Officer reports to the Chief Technology Officer and works closely with the Chief Legal Officer to ensure that all disclosure or reporting requirements are satisfied if an incident were to occur. The Chief Security & Risk Officer leads Parsons’ overall cybersecurity function and provides quarterly reports to the Audit and Risk Committee on our cybersecurity risks, including briefings on our cybersecurity risk management program and cybersecurity incidents.
Cybersecurity Risk Role of Management [Text Block]	Our Chief Security & Risk Officer reports to the Chief Technology Officer and works closely with the Chief Legal Officer to ensure that all disclosure or reporting requirements are satisfied if an incident were to occur. The Chief Security & Risk Officer leads Parsons’ overall cybersecurity function and provides quarterly reports to the Audit and Risk Committee on our cybersecurity risks, including briefings on our cybersecurity risk management program and cybersecurity incidents. The Audit and Risk Committee also receives periodic presentations on relevant cybersecurity topics as part of the Committee and the Board’s continuing education on topics that impact public companies. Our Chief Security & Risk Officer supervises efforts to prevent, detect, mitigation and remediate cybersecurity risks and incidents through various means, which include briefings from internal security personnel; threat intelligence and other information obtained from governmental, public or private sources, including external cybersecurity service providers; and alerts and reports produced by security tools deployed in the IT environment. Our Chief Security & Risk Officer is responsible for assessing and managing our material risks from cybersecurity threats and has primary responsibility for leading our overall cybersecurity risks management program and supervises both our internal cybersecurity personnel and our external cybersecurity service providers. Our Chief Security & Risk Officer has significant global experience in managing and leading IT and cybersecurity teams.
Cybersecurity Risk Management Positions or Committees Responsible [Flag]	true
Cybersecurity Risk Management Positions or Committees Responsible [Text Block]	Our Chief Security & Risk Officer is responsible for assessing and managing our material risks from cybersecurity threats and has primary responsibility for leading our overall cybersecurity risks management program and supervises both our internal cybersecurity personnel and our external cybersecurity service providers.
Cybersecurity Risk Management Expertise of Management Responsible [Text Block]	Our Chief Security & Risk Officer supervises efforts to prevent, detect, mitigation and remediate cybersecurity risks and incidents through various means, which include briefings from internal security personnel; threat intelligence and other information obtained from governmental, public or private sources, including external cybersecurity service providers; and alerts and reports produced by security tools deployed in the IT environment. Our Chief Security & Risk Officer is responsible for assessing and managing our material risks from cybersecurity threats and has primary responsibility for leading our overall cybersecurity risks management program and supervises both our internal cybersecurity personnel and our external cybersecurity service providers. Our Chief Security & Risk Officer has significant global experience in managing and leading IT and cybersecurity teams.
Cybersecurity Risk Process for Informing Management or Committees Responsible [Text Block]	Chief Security & Risk Officer supervises efforts to prevent, detect, mitigation and remediate cybersecurity risks and incidents through various means, which include briefings from internal security personnel; threat intelligence and other information obtained from governmental, public or private sources, including external cybersecurity service providers; and alerts and reports produced by security tools deployed in the IT environment.
Cybersecurity Risk Management Positions or Committees Responsible Report to Board [Flag]	true

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ 54,180	$ 39,750	$ 235,053	$ 161,149	$ 96,664

Insider Trading Arrangements

Insider Trading Arrangements	3 Months Ended
	Dec. 31, 2024
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Insider Trading Policies and Pr

Insider Trading Policies and Procedures	12 Months Ended
	Dec. 31, 2024
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true

Description of Operations

Description of Operations	12 Months Ended
	Dec. 31, 2024
Description Of Operations Disclosure [Abstract]
Description of Operations	1. Description of Operations Organization Parsons Corporation, a Delaware corporation, and its subsidiaries (collectively, the “Company”) provide sophisticated design, engineering and technical services, and smart and agile software to the United States federal government and Critical Infrastructure customers worldwide. The Company performs work in various foreign countries through local subsidiaries, joint ventures and foreign offices maintained to carry out specific projects.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	2. Summary of Significant Accounting Policies Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of Parsons Corporation and its subsidiaries and affiliates which it controls. Interests in joint ventures that are controlled by the Company, or for which the Company is otherwise deemed to be the primary beneficiary, are consolidated. For joint ventures in which the Company does not have a controlling interest, but exerts significant influence, the Company applies the equity method of accounting. Intercompany accounts and transactions are eliminated in consolidation. Certain amounts may not foot due to rounding. Use of Estimates The preparation of the consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual amounts could differ from those estimates. The Company’s most significant estimates and judgments involve revenue recognition with respect to the determination of the costs to complete contracts and transaction price; determination of self-insurance reserves; useful lives of property and equipment and intangible assets; valuation of deferred income tax assets and uncertain tax positions, among others. ESOP The Company maintains a non-leveraged ESOP for eligible employees, for which the Company contributes shares of its own stock to the ESOP trust each year. Throughout the year, as employee services are rendered, the Company records compensation expense based on salaries of eligible employees. At each reporting period, the shares held within the ESOP or committed to be contributed to the ESOP are adjusted to their redemption value through an offsetting charge or credit to retained earnings. Treasury Stock The Company records treasury stock purchases under the cost method whereby the entire cost of the acquired stock is recorded as treasury stock. The Company records the reissuance of treasury stock using the first-in, first-out method of accounting. Contributions of 633,033 shares, 915,113 shares, and 1,188,129 shares of common stock were made to the ESOP in 2024, 2023 and 2022, respectively. Share Repurchases During the third quarter of 2021, the Company’s Board of Directors authorized the Company to acquire a number of shares of Common Stock having an aggregate market value of not greater than $ 100,000,000 from time to time. The Board further amended this authorization in February 2024 to restore the repurchase capacity to $ 100 million and removed the $ 25 million quarterly cap on such repurchases. At the time of the February 2024 authorization, the Company had repurchased shares with an aggregated market value (including fees) of $ 54.7 million. The aggregate market value of shares of Common Stock the Company is authorized to acquire is now not greater than $ 154.7 million. Repurchased shares of common stock are retired and included in “Repurchases of common stock” in cash flows from financing activities in the Consolidated Statements of Cash Flows. Earnings per Share Basic earnings per common share (“EPS”) is calculated by dividing Net income by the weighted average number of common shares outstanding during the year. Diluted earnings per common share is calculated using the if-converted method by dividing adjusted net income by adjusted weighted average outstanding shares, assuming conversion of all potentially dilutive securities. Upon contribution to the ESOP, the shares become outstanding and are included within the earnings per share computations. Revenue Recognition In accordance with Account Standard Update ("ASC") 606 - Revenue From Contracts With Customers , the Company follows the five-step process in ASC 606 to recognize revenue: 1. Identify the contract 2. Identify performance obligations 3. Determine the transaction price 4. Allocate the transaction price 5. Recognize revenue Contracts —Revenue is derived from long-term contracts with customers whereby the Company provides planning, design, engineering, technical, and construction and program management services. The Company has contracts with the United States federal government that contain provisions requiring compliance with the United States Federal Acquisition Regulation (“FAR”) and the United States Cost Accounting Standards (“CAS”). These regulations are generally applicable to all of the Company’s federal government contracts and are partially or fully incorporated in some local and state agency contracts. Most of the Company’s federal government contracts are subject to termination at the convenience of the client. These contracts typically provide for reimbursement of costs incurred and payment of fees earned through the date of such termination. The Company enters into the following types of contracts with its customers: Cost-Plus—Under cost-plus contracts, the Company is reimbursed for allowable or otherwise defined costs incurred, plus a fee. The contracts may also include incentives for various performance criteria, including quality, timeliness, safety and cost-effectiveness. In addition, costs are generally subject to review by clients and regulatory audit agencies, and such reviews could result in costs being disputed as non-reimbursable under the terms of the contract. Time-and-Materials—Under time-and-materials contracts, hourly billing rates are negotiated and charged to clients based on the actual time spent on a project. In certain cases, these contracts may be subject to maximum contract values. In addition, clients reimburse actual out-of-pocket costs for materials and other direct incidental expenditures that are incurred in connection with the performance under the contract. Fixed-Price—The Company enters into two types of fixed-price contracts: firm fixed-price (“FFP”) and fixed-price per unit (“FPPU”). Under FFP contracts, clients pay an agreed fixed-amount negotiated in advance for a specified scope of work. Contract Costs —Contract costs consist of direct costs on contracts, including labor and materials, amounts payable to subcontractors, direct overhead costs and equipment expense (primarily depreciation, fuel, maintenance and repairs). All contract costs are recorded as incurred. Changes to estimated contract costs, either due to unexpected events or revisions to management’s initial estimates, for a given project are recognized in the period in which they are determined. Pre-contract costs are expensed as incurred unless they are expected to be recovered from the client, generate or enhance resources that will be used in satisfying performance obligations in the future and directly relate to an existing or anticipated contract. Costs to mobilize equipment and labor to a job site, prior to substantive work beginning (“mobilization costs”) are capitalized as incurred and amortized over the expected duration of the contract. Additionally, the Company may incur incremental costs to obtain certain contracts, such as selling and market costs, bid and proposal costs, sales commissions, and legal fees, certain of which can be capitalized if they are recoverable under the contract. Capitalized contract costs are included in other current assets on the consolidated balance sheets and were not material as of December 31, 2024 and December 31, 2023. Performance Obligations —A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC 606. The transaction price of a contract is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. To the extent a contract is deemed to have multiple performance obligations, the Company allocates the transaction price of the contract to each performance obligation using our best estimate of the standalone selling price of each distinct good or service in the contract. The Company determines the relative standalone selling price utilizing observable prices for the sale of the underlying goods or services. Contracts are considered to have a single performance obligation if the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts or is not distinct in the context of the contract, which is mainly because the Company provides a significant service of integrating a complex set of tasks and components into a single project or capability. Engineering and construction contracts are generally accounted for as a single performance obligation while our engineering and construction supervision contracts are accounted for as two separate performance obligations. When providing construction supervision services, the Company is not liable for the construction of the asset, but has an overall responsibility to oversee, coordinate, measure, and evaluate the quality of construction work and the performance of the construction contractor on behalf of the customer. Customers are generally billed as the Company satisfies its performance obligations and payment terms typically range from 30 to 120 days from the invoice date. Billings under certain fixed-price contracts may be based upon the achievement of specified milestones, while some arrangements may require advance customer payment. The Company’s contracts generally do not include a significant financing component. Variable Consideration —The transaction price for the Company’s contracts may include variable consideration, which includes increases to transaction price for approved and unpriced change orders, claims and incentives, and reductions to transaction price for liquidated damages. Change orders, claims and incentives are generally not distinct from the existing contract due to the significant integration service provided in the context of the contract and are accounted for as a modification of the existing contract and performance obligation. The Company estimates variable consideration for a performance obligation utilizing one of the two prescribed methods, depending on which method better predicts the amount of consideration to which the Company will be entitled (or the amount the Company expects to incur in the case of liquidated damages). Such methods are: (a) the expected value method, whereby the amount of variable consideration to be recognized represents the sum of probability weighted amounts in a range of possible consideration amounts, and (b) the most likely amount method, whereby the amount of variable consideration to be recognized represents the single most likely amount in a range of possible consideration amounts. When applying these methods, the Company considers all information that is reasonably available, including historical, current and estimates of future performance. The expected value method is utilized in situations where a contract contains a large number of possible outcomes, while the most likely amount method is utilized in situations where a contract has only two possible outcomes. The Company includes variable consideration in the estimated transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur or when the uncertainty associated with the variable consideration is resolved. The Company’s estimates of variable consideration and determination of whether to include estimated amounts in transaction price are based largely on an assessment of anticipated performance and all information (historical, current and forecasted) that is reasonably available. The effect of variable consideration on the transaction price of a performance obligation is recognized as an adjustment to revenue on a cumulative catch-up basis. Change Orders —Change orders, which are a normal and recurring part of business, may include changes in specifications or design, manner of performance, facilities, equipment, materials, sites and period of completion of the work. The Company or customer may initiate change orders. Most change orders are not distinct from the existing contract and are accounted for as part of that existing contract. The effect of a change order on the transaction price and measure of progress for the performance obligation to which it relates is recognized as an adjustment to revenues (either as an increase in or a reduction of revenues) on a cumulative catch-up basis. Revenues from unpriced change orders are recognized to the extent of the amounts the Company expects to recover, consistent with the variable consideration policy discussed above. If it is probable that a reversal of revenues will occur, the costs attributable to change orders are treated as contract costs without incremental revenues. To the extent change orders included in the price are not resolved in the Company’s favor, there could be reductions in, or reversals of previously reported amounts of, revenues and profits, and charges against current earnings, which could be material. Claims Revenue —Claims revenue are amounts in excess of agreed contract prices that the Company seeks to collect from clients or others for customer-caused delays, errors in specifications and designs, contract terminations, change orders that are in dispute, or other causes of unanticipated additional contract costs, including factors outside of our control, and therefore the Company believes it is entitled to additional compensation. Claims revenue, when recorded, is only recorded to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur. The Company includes certain claims in the transaction price when the claims are legally enforceable, the Company considers collection to be probable and believes it can reliably estimate the ultimate value. The Company continues to engage in negotiations with its customers on outstanding claims. However, these claims may be resolved at amounts that differ from current estimates, which could result in increases or decreases in future estimated contract profits or losses. Warranties —In most cases, contracts include assurance-type warranties that the Company’s performance is free from material defect and consistent with the specifications of the Company’s contracts, which do not give rise to a separate performance obligation. To the extent the warranty terms provide the customer with an additional service, such as extended maintenance services, such warranty is accounted for as a separate performance obligation. Revenue recognized over time —The Company’s performance obligations are generally satisfied over time as work progresses because of continuous transfer of control to the customer and the Company has the right to bill the customer as costs are incurred. Typically, revenue is recognized over time using an input measure (i.e. costs incurred to date relative to total estimated costs at completion) to measure progress. The Company generally uses the cost-to-cost measure of progress method because it best depicts the transfer of control to the customer which occurs as the Company incurs costs on its contracts. Under the cost-to-cost measure of progress method, the extent of progress towards completion is measured based on the ratio of total costs incurred to-date to the total estimated costs at completion of the performance obligation. Revenues, including estimated fees or profits, are recorded proportionally as costs are incurred. Any expected losses on construction-type contracts in progress are charged to earnings, in total, in the period the losses are identified. The Company recognizes adjustments in estimated profit on contracts under the cumulative catch-up method. Under this method, the impact of the adjustment on profit recorded to date is recognized in the period the adjustment is identified. Revenue and profit in future periods of contract performance is recognized using the adjusted estimate. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, the Company recognizes the total loss in the period it is identified. Right to invoice practical expedient —For performance obligations satisfied over time where the Company has a right to consideration from a customer in an amount that corresponds directly with the value of the Company’s performance to-date, the Company recognizes revenue in the amount to which it has a right to invoice. For the Company’s reimbursable services contracts, revenue is recognized using the right to invoice practical expedient, or on a cost-to-cost measure of progress method. The Company will select the method that best represents progress on a project. Revenue recognized at a point in time —For performance obligations satisfied at a point in time, revenue is recognized when the services are performed, control is transferred, and the performance obligation is complete. The Company recognizes revenue at a point in time for vehicle inspection services. Revenue related to the inspection service is recognized for each vehicle inspection at the point the Company has completed the inspection. In the Company’s industry, recognition of profit on long-term contracts requires the use of assumptions and estimates related to total contract revenue and in particular estimated claims revenue, total estimated cost at completion, and the measurement of progress towards completion. Estimates are continually evaluated as work progresses and are revised when necessary. When a change in estimate is determined to have an impact on contract profit, the Company records a positive or negative adjustment to the consolidated statements of income. Cash Equivalents The Company considers all highly liquid investments with original maturities of less than three months to be cash equivalents. Cash equivalent investments are carried at cost, which approximates fair value, and consist primarily of United States Treasuries, time deposits, and other forms of short-term fixed income investments. Restricted Cash and Investments Restricted cash and investments held in trust accounts represent collateral for certain incentive programs. Accounts Receivable, Net Accounts receivable includes billed and unbilled amounts and are recognized in the period when the Company’s rights to receive consideration are unconditional. The Company establishes an allowance for doubtful accounts based on consideration of trends in actual and forecasted credit quality of clients, including delinquency and payment history, type of client, such as a government agency or commercial sector client, and general economic conditions and particular industry conditions that may affect a client’s ability to pay. Past due receivable balances are written off when internal collection efforts have been unsuccessful in collecting the amounts due. Contract Assets and Contract Liabilities Projects with performance obligations recognized over time that have revenue recognized to-date in excess of cumulative billings and unbilled accounts receivable are reported on our consolidated balance sheets as “Contract assets”. Contract retentions, included in contract assets, represent amounts withheld by clients, in accordance with underlying contract terms, until certain conditions are met or the project is completed. The operating cycle for certain long-term contracts may extend beyond one year, and, accordingly, collection of retainage on those contracts may extend beyond one year. Contract assets are reclassified to accounts receivable when the right to consideration becomes unconditional. Contract liabilities on uncompleted contracts represent the excess of cash collected from clients and billings to clients on contracts in advance of work performed over the amount of revenue recognized and provisions for losses. The majority of these amounts are expected to be earned within 12 months and are classified as current liabilities. Concentration of Credit Risk Financial instruments which potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivables. The Company’s cash is primarily held with major banks and financial institutions throughout the world. At times, cash balances may be in excess of the amount insured. The Company is involved in a significant volume of contracts with the United States federal government and state and local governments. Approximately 59 %, 55 %, and 53 % of consolidated revenues for the years ended December 31, 2024, December 31, 2023 and December 31, 2022, respectively, and approximately 23 % and 18 % of accounts receivable as of December 31, 2024 and December 31, 2023, respectively were derived from contracts with the United States federal government. No other customers represented 10% or more of consolidated revenues or accounts receivable in any of the periods presented. Two customer sets within the United States federal government represent over 20% of total Company revenue for the year ended December 31, 2024. In order to mitigate the credit risk associated with customers, the Company performs periodic credit evaluations of its customers’ financial condition. Property and Equipment Property and equipment are stated at cost and are shown net of accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Depreciation of leasehold improvements is computed using the straight-line method over the shorter of their estimated useful lives or the remaining term of the lease. The cost of assets retired or otherwise disposed of and the related accumulated depreciation are eliminated from the accounts, and any gain or loss thereon is included in net income. Expenditures for maintenance and repairs are expensed as incurred. Property and equipment are reviewed for impairment when events or circumstances change that indicate they may not be recoverable. Impairment losses are recognized when estimated future cash flows expected to result from the use of the assets and their eventual disposition are less than their carrying amount, in which case the asset is written down to its fair value. Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease ROU assets and current and long-term operating lease liabilities in the consolidated balance sheets. Finance leases are included in other noncurrent assets, accrued expenses and other current liabilities and other long-term liabilities in the consolidated balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, incremental borrowing rates are used based on the information available at commencement date in determining the present value of lease payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives. Lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. We have lease agreements with lease and non-lease components where the lease consideration is allocated between the components based on relative standalone prices. For real property leases, allocations of lease consideration between lease and non-lease components are immaterial. For certain equipment leases, such as vehicles, we account for the lease and non-lease components as a single lease component. Additionally, for certain equipment leases, we apply a portfolio approach to effectively account for the operating lease ROU assets and liabilities. Equity-Based Compensation The Company measures the value of services received from employees and directors in exchange for an equity-based award based on the grant date fair value. The Company issues equity-based awards that settle in shares of the Company’s common stock. Awards containing performance measures are adjusted at each reporting period for the number of shares expected to be earned. Compensation cost for performance awards are trued-up at each reporting period for the number of shares expected to be earned pro-rated for the portion of the requisite service period rendered. The Company recognizes compensation costs for these awards on either a straight-line or accelerated basis over the vesting period of the award in selling, general and administrative expense in the consolidated statements of income. For awards that include market conditions, the grant date fair value is determined using a Monte Carlo simulation. Business Combinations The Company accounts for business combinations using the acquisition method, under which the purchase price of an acquired company is allocated to the tangible and intangible assets acquired and the liabilities assumed on the basis of their fair values at the date of acquisition. Any excess of purchase price over the fair value of tangible and intangible assets acquired and liabilities assumed is allocated to goodwill. The determination of fair values of assets acquired and liabilities assumed requires the Company to make estimates and use valuation techniques when a market value is not readily available. In determining the fair value of acquired intangible assets from our business acquisitions, the Company uses the multi-period excess earnings method to value customer relationships and backlog and values developed technologies using the relief-from royalty method. The Company’s determination of the fair value of the intangible assets acquired involves the use of significant estimates and assumptions related to discount rates, revenue growth rates, projected margins, and customer revenue attrition rates. Certain business acquisitions include contingent consideration. Contingent consideration is recorded at its fair value, using a Black-Scholes model, within other liabilities or other long-term liabilities, as appropriate. The fair value of contingent consideration involves the use of significant estimates and assumptions related to risks associated with earnout, i.e. risk in the underlying metric, risk in the earnout structure, counterparty credit risk, projected revenue, the revenue discount rate, the revenue volatility, and the Company's credit adjusted discount rate. Subsequent adjustments to these assumptions can cause changes to the measure of contingent consideration. The Company adjusts the preliminary purchase price allocation, as necessary, during the measurement period of up to one year after the acquisition closing date as the Company obtains more information as to facts and circumstances existing at the acquisition date. Acquisition-related costs are recognized separate from the acquisition and are expensed as incurred. Consolidation of Joint Ventures and Variable Interest Entities The Company participates in joint ventures, which include partnerships and partially owned limited liability corporations, to bid, negotiate and complete specific projects. The Company is required to consolidate these joint ventures if it holds the majority voting interest or if the joint venture is determined to be a variable interest entity (“VIE”) for which the Company is the primary beneficiary, as described below. A VIE is an entity with one or more of the following characteristics: (a) the total equity investment at risk is not sufficient to permit the entity to finance its activities without additional financial support; (b) as a group, the holders of the equity investment at risk lack the ability to make certain decisions, the obligation to absorb expected losses or the right to receive expected residual returns; or (c) an equity investor has voting rights that are disproportionate to its economic interest and substantially all of the entity’s activities are on behalf of the investor with disproportionately low voting rights. The Company’s VIEs may be funded through contributions, loans and/or advances from the joint venture partners or by advances and/or letters of credit provided by clients. Certain VIEs are directly governed, managed, operated and administered by the joint venture partners. Others have no employees and, although these entities own and hold the contracts with the clients, the services required by the contracts are typically performed by the joint venture partners or by other subcontractors. The Company is considered the primary beneficiary and required to consolidate a VIE if it has the power to direct the activities that most significantly impact that VIE’s economic performance, and the obligation to absorb losses or the right to receive benefits of that VIE that could potentially be significant to the VIE. In determining whether the Company is the primary beneficiary, significant assumptions and judgments include the following: (1) identifying the significant activities and the parties that have the power to direct them; (2) reviewing the governing board composition and participation ratio; (3) determining the equity, profit and loss ratio; (4) determining the management-sharing ratio; (5) reviewing employment terms; and (6) reviewing the funding and operating agreements. Examples of significant activities currently being performed by the Company’s significant consolidated and unconsolidated joint ventures include engineering and design services; management consulting services; procurement and construction services; program management; construction management; and operations and maintenance services. If the Company determines that the power to direct the significant activities is shared by two or more joint venture parties, then there is no primary beneficiary and no party consolidates the VIE. In making the shared-power determination, the Company analyzes the key contractual terms, governance, related party and de facto agency as they are defined in the accounting standard, and other arrangements. Goodwill The Company performs a goodwill impairment test annually, on October 1 st of each year and additionally, performs a quarterly qualitative assessment to address whether a triggering event has occurred that would require an impairment test in the interim period. For purposes of impairment testing, goodwill is allocated to the applicable reporting units based on the current reporting structure. Reporting units are operating segments or components of operating segments where discrete financial information is available and segment management regularly reviews the operating results. When evaluating goodwill for impairment, the Company may decide to first perform a qualitative assessment, or “step zero” impairment test, to determine whether it is more likely than not that impairment has occurred. If the Company does not perform a qualitative assessment, or if the Company determines that it is not more likely than not that the fair value of its reporting units exceeds their carrying amounts, the Company performs a quantitative assessment and calculates the estimated fair value of the respective reporting unit. If the carrying amount of a reporting unit exceeds its fair value, an impairment loss is recognized in the amount the carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The Company’s decision to perform a qualitative impairment assessment in a given year is influenced by a number of factors, including the significance of the excess of the Company’s estimated fair value over carrying value at the last quantitative assessment date, the amount of time in between quantitative fair value assessments, and the date of its acquisitions, if any. Intangible Assets Intangible assets with finite lives arise from business acquisitions and are amortized based on the period over which the contractual or economic benefit of the intangible assets are expected to be realized or on a straight-line basis over the useful lives of the underlying assets, ranging from one to sixteen years . These primarily consist of customer relationships, developed technology, backlog, and covenants not to compete. When in

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2024
Business Combinations [Abstract]
Acquisitions	3. Acquisitions BCC Engineering, LLC On November 1, 2024, the Company acquired a 100 % ownership interest in BCC Engineering, LLC ("BCC") a privately owned company, for $ 232.7 million from cash on hand. BCC is a full-service engineering firm that provides planning, design, and management services for transportation, civil and structural engineering projects in Florida, Georgia, Texas, South Carolina, and Puerto Rico. This acquisition strengthens Parsons’ position as an infrastructure leader while expanding the company’s reach in the southeastern United States. In connection with this acquisition, the Company recognized $ 4.2 million of acquisition-related expenses in “Selling, general and administrative expense” in the consolidated statements of income for the year ended December 31, 2024, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition. The following table summarizes the acquisition date fair value of the purchase consideration transferred (in thousands): Amount Cash and cash equivalents $ 2,839 Accounts receivable 24,142 Contract assets 16,649 Prepaid expenses and other current assets 2,483 Right of use assets, operating leases 9,438 Property and Equipment 1,586 Other noncurrent assets 1,743 Goodwill 174,532 Intangible assets 32,400 Accounts payable ( 8,668 ) Accrued expenses and other current liabilities ( 7,236 ) Contract liabilities ( 4,446 ) Short-term lease liabilities, operating leases ( 1,977 ) Deferred income taxes ( 2,203 ) Long-term lease liabilities, operating leases ( 7,462 ) Other long-term liabilities ( 1,155 ) Net assets acquired $ 232,665 Of the total purchase price, the following values were preliminarily assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships $ 6,500 4 Backlog 23,400 4 Non-compete agreements 1,700 3 Other $ 800 1 Amortization expense of $ 1.5 million related to these intangible assets was recorded for the year ended December 31, 2024. The entire value of goodwill was assigned to the Critical Infrastructure reporting unit and represents synergies expected to be realized from this business combination. $ 45.8 million of goodwill is deductible for tax purposes. The amount of revenue generated by BCC and included within consolidated revenue is $ 20.3 million for the year ended December 31, 2024. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition. The Company is still in the process of finalizing its valuation of the assets and liabilities acquired. Supplemental Pro Forma Information (Unaudited) Supplemental information of unaudited pro forma operating results assuming the BCC acquisition had been consummated as of the beginning of fiscal year 2023 (in thousands) is as follows: 2024 2023 (unaudited) (unaudited) Pro forma Revenue $ 6,838,190 $ 5,537,090 Pro forma Net Income including noncontrolling interests 286,948 189,200 The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired intangible assets, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented. BlackSignal Technologies, LLC. On August 16, 2024, the Company acquired a 100 % ownership interest in BlackSignal Technologies, LLC, ("BlackSignal") a privately-owned company, for $ 203.7 million from cash on hand. Headquartered in Chantilly, Virginia, BlackSignal is a next-generation digital signal processing, electronic warfare, and cyber security provider built to counter near peer threats. Parsons believes that the acquisition will expand Parsons' customer base across the Department of Defense and Intelligence Community and significantly strengthen Parsons' positioning within cyber warfare, while adding new capabilities in the counterspace radio frequency domain. In connection with this acquisition, the Company recognized $ 2.5 million of acquisition-related expenses in “Selling, general and administrative expense” in the consolidated statements of income for the year ended December 31, 2024, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition. The following table summarizes the acquisition date fair value of the purchase consideration transferred (in thousands): Amount Cash and cash equivalents $ 4,917 Accounts receivable 5,171 Contract assets 3,209 Prepaid expenses and other current assets 447 Right of use assets, operating leases 5,370 Property and Equipment 997 Goodwill 119,663 Intangible assets 97,600 Other assets 145 Accounts payable ( 951 ) Accrued expenses and other current liabilities ( 4,999 ) Short-term lease liabilities, operating leases ( 800 ) Deferred income taxes ( 22,461 ) Long-term lease liabilities, operating leases ( 4,570 ) Net assets acquired $ 203,738 Of the total purchase price, the following values were preliminarily assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships $ 73,900 14 Backlog 11,700 3 Developed technologies 5,200 5 Non-compete agreements 6,100 3 Other $ 700 1 Amortization expense of $ 4.3 million related to these intangible assets was recorded for the year ended December 31, 2024. The entire value of goodwill was assigned to the Federal Solutions reporting unit and represents synergies expected to be realized from this business combination. $ 15.7 million of goodwill is deductible for tax purposes. The amount of revenue generated by BlackSignal and included within consolidated revenue is $ 22.7 million for the year ended December 31, 2024. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition. Supplemental Pro Forma Information (Unaudited) Supplemental information of unaudited pro forma operating results assuming the BlackSignal acquisition had been consummated as of the beginning of fiscal year 2023 (in thousands) is as follows: 2024 2023 (unaudited) (unaudited) Pro forma Revenue $ 6,782,552 $ 5,481,036 Pro forma Net Income including noncontrolling interests 283,900 185,954 The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired intangible assets, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented. I.S. Engineers, LLC On October 31, 2023, the Company entered into a Membership Interest Purchase Agreement to acquire a 100 % ownership interest in I.S. Engineers, LLC (“I.S. Engineers”), a privately-owned company, for $ 12.2 million in cash. Headquartered in Texas, I.S. Engineers provides full service consulting specializing in transportation engineering, including roads and highways, and program management. The acquisition was entirely funded by cash on-hand. In connection with this acquisition, the Company recognized $ 0.3 million of acquisition related “Selling, general and administrative expense” in the consolidated statements of income for the year ended December 31, 2023, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition. The Company allocated the purchase price to the appropriate classes of tangible assets and liabilities and assigned the excess of $ 11.9 million entirely to goodwill. The entire value of goodwill was assigned to the Critical Infrastructure reporting unit and represents synergies expected to be realized from this business combination. No goodwill is deductible for income tax purposes. Sealing Technologies, Inc. On August 23, 2023, the Company acquired a 100 % ownership interest in Sealing Technologies, Inc (“SealingTech”), a privately-owned company, for $ 176.0 million in cash and up to an additional $ 25 million in the event an earn out revenue target is exceeded. The Company borrowed $ 175 million under the Credit Agreement to partially fund the acquisition. Headquartered in Maryland, SealingTech expands Parsons’ customer base across the Department of Defense and Intelligence Community, and further enhances the company’s capabilities in defensive cyber operations; integrated mission-solutions powered by artificial intelligence (AI) and machine learning (ML); edge computing and edge access modernization; critical infrastructure protection; and secure data management. In connection with this acquisition, the Company recognized $ 3.3 million of acquisition-related expenses in “Selling, general and administrative expense” in the consolidated statements of income for the year ended December 31, 2023, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition. The Company agreed to pay the selling shareholders up to an additional $ 25 million in the event an earn out revenue target of $ 110 million is exceeded during the fiscal year ended December 31, 2024. The earn out payment due and payable by the Company to the selling shareholders shall be equal to (i) five-tenths ( 0.5 ), multiplied by (ii) the difference of (A) the actual earn out revenue minus (B) the earn out revenue target; provided, however, that in no event shall the earn out payment exceed $ 25 million. In the event that the earn out revenue is less than or equal to the earn out revenue target, the earn out payment shall be zero . The earn out payment, if any, shall be paid by the Company to the selling shareholders within 15 days following the date the earn out statement becomes final and binding on both parties. The fair value of the earn out (contingent consideration in the table below) was calculated using a Black-Scholes model. See "Note 2— Summary of Significant Accounting Policies" and "Note 18—Fair Value " for further information on how the fair value of contingent consideration is determined. The following table summarizes the acquisition date fair value of the purchase consideration transferred (in thousands): Amount Cash paid at closing $ 176,028 Fair value of contingent consideration to be achieved 3,231 Total purchase price $ 179,259 The estimated fair value of the SealingTech contingent consideration as of December 31, 2024 and December 31, 2023 was zero and $ 2.3 million, respectively. The change in fair value to zero resulted in recording a $ 2.3 million gain to "other income (expense), net" in the consolidated financial statements. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed based on the purchase price allocation as of the date of acquisition (in thousands): Amount Cash and cash equivalents $ 8,133 Accounts receivable 17,889 Contract assets 2,946 Prepaid expenses and other current assets 1,379 Property and equipment 2,025 Right of use assets, operating leases 1,836 Deferred tax assets 357 Goodwill 90,593 Intangible assets 75,000 Accounts payable ( 15,987 ) Accrued expenses and other current liabilities ( 2,408 ) Contract liabilities ( 668 ) Short-term lease liabilities, operating leases ( 418 ) Long-term lease liabilities, operating leases ( 1,418 ) Net assets acquired $ 179,259 Of the total purchase price, the following values were preliminarily assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships $ 40,000 14 Backlog 26,000 3 Developed technologies 8,000 3 Other $ 1,000 1 Amortization expense of $ 12.9 million and $ 7.0 million related to these intangible assets was recorded for the years ended December 31, 2024 and December 31, 2023, respectively. The entire value of goodwill was assigned to the Federal Solutions reporting unit and represents synergies expected to be realized from this business combination. The entire value of goodwill is deductible for tax purposes. The amount of revenue generated by SealingTech and included within consolidated revenue is $ 34.1 million for the year December 31, 2023. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition. Supplemental Pro Forma Information (Unaudited) Supplemental information of unaudited pro forma operating results assuming the SealingTech acquisition had been consummated as of the beginning of fiscal year 2022 (in thousands) is as follows: 2023 2022 (unaudited) (unaudited) Pro forma Revenue $ 5,525,099 $ 4,262,525 Pro forma Net Income including noncontrolling interests 216,157 107,937 The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired intangible assets, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented. IPKeys Power Partners On April 13, 2023, the Company entered into a merger agreement to acquire a 100 % ownership interest in IPKeys Power Partners (“IPKeys”), a privately-owned company, for $ 43.0 million in cash. The merger brings IPKeys' established customer base, expanding Parsons' presence in two rapidly growing end markets: grid modernization and cyber resiliency for critical infrastructure. Headquartered in Tinton Falls, New Jersey, IPKeys is a trusted provider of enterprise software platform solutions that is actively delivering cyber and operational security to hundreds of electric, water, and gas utilities across North America. The acquisition was entirely funded by cash on-hand. In connection with this acquisition, the Company recognized $ 0.6 million of acquisition-related expenses in “Selling, general and administrative expense” in the consolidated statements of income for the year ended December 31, 2023, respectively, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed based on the purchase price allocation as of the date of acquisition (in thousands): Amount Cash and cash equivalents $ 126 Accounts receivable 3,937 Contract assets 834 Prepaid expenses and other current assets 455 Property and equipment 86 Right of use assets, operating leases 1,105 Other noncurrent assets 152 Goodwill 22,407 Intangible assets 23,000 Accounts payable ( 541 ) Accrued expenses and other current liabilities ( 1,768 ) Contract liabilities ( 1,936 ) Short-term lease liabilities, operating leases ( 343 ) Deferred tax liabilities ( 3,713 ) Long-term lease liabilities, operating leases ( 762 ) Net assets acquired $ 43,039 Of the total purchase price, the following values were assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships (1) $ 15,900 16 Developed technologies 7,000 11 Other $ 100 1 (1) The acquired business is a SaaS commercial business. Backlog for this type of business is included as customer relationships. Amortization expense of $ 1.6 million and $ 1.4 million related to these intangible assets was recorded for the years ended December 31, 2024 and December 31, 2023, respectively. The entire value of goodwill was assigned to the Critical Infrastructure reporting unit and represents synergies expected to be realized from this business combination. $ 0.9 million of goodwill is deductible for tax purposes. The amount of revenue generated by IPKeys and included within consolidated revenue is $ 9.3 million for the year ended December 31, 2023. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition. Supplemental Pro Forma Information (Unaudited) Supplemental information of unaudited pro forma operating results assuming the IPKeys acquisition had been consummated as of the beginning of fiscal year 2022 (in thousands) is as follows: 2023 2022 (unaudited) (unaudited) Pro forma Revenue $ 5,445,604 $ 4,207,967 Pro forma Net Income including noncontrolling interests 209,773 123,257 The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired intangible assets, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented. Xator Corporation On May 31, 2022, the Company acquired a 100 % ownership interest in Xator Corporation (“Xator”), a privately-owned company, for $ 387.5 million in cash. The Company borrowed $ 300 million under the Credit Agreement to partially fund the acquisition. Xator expands Parsons’ customer base and brings differentiated technical capabilities in critical infrastructure protection, counter-unmanned aircraft systems (cUAS), intelligence and cyber solutions, biometrics, and global threat assessment and operations. In connection with this acquisition, the Company recognized $ 7.7 million of acquisition-related expenses in “Selling, general and administrative expense” in the consolidated statements of income for the year ended December 31, 2022, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition. The following table summarizes the estimated fair values of the assets acquired and liabilities assumed based on the purchase price allocation as of the date of acquisition (in thousands): Amount Cash and cash equivalents $ 8,935 Accounts receivable 7,393 Contract assets 24,332 Prepaid expenses and other current assets 3,615 Property and equipment 1,699 Right of use assets, operating leases 7,517 Goodwill 257,934 Investments in and advances to unconsolidated joint ventures 698 Intangible assets 123,500 Other noncurrent assets 9,156 Accounts payable ( 6,626 ) Accrued expenses and other current liabilities ( 31,309 ) Contract liabilities ( 2,631 ) Short-term lease liabilities, operating leases ( 2,371 ) Long-term lease liabilities, operating leases ( 5,146 ) Other long-term liabilities ( 9,156 ) Net assets acquired $ 387,540 Of the total purchase price, the following values were assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships $ 37,000 15 Backlog 81,000 6 Trade name 4,000 1 Developed technologies 1,000 3 Non-compete agreements $ 500 3 Amortization expense of $ 16.5 million, $ 18.1 million and $ 11.9 million related to these intangible assets was recorded for the year ended December 31, 2024, December 31, 2023, and December 31, 2022, respectively. The entire value of goodwill was assigned to the Federal Solutions reporting unit and represents synergies expected to be realized from this business combination. Goodwill in its entirety is deductible for tax purposes. The amount of revenue generated by Xator and included within consolidated revenue is $ 157.8 million for the year ended December 31, 2022. The Company has determined that the presentation of net income from the date of acquisition is impracticable due to the integration of general corporate functions upon acquisition. Supplemental Pro Forma Information (Unaudited) Supplemental information of unaudited pro forma operating results assuming the Xator acquisition had been consummated as of the beginning of fiscal year 2021 (in thousands) is as follows: 2022 2021 (unaudited) (unaudited) Pro forma Revenue $ 4,302,448 $ 3,949,562 Pro forma Net Income including noncontrolling interests 139,901 91,770 The unaudited pro forma supplemental information is based on estimates and assumptions which the Company believes are reasonable and reflects the pro forma impact of additional amortization related to the fair value of acquired intangible assets, and the pro forma impact of reflecting acquisition costs, which consisted of legal, advisory and due diligence fees and expenses. This supplemental pro forma information has been prepared for comparative purposes and does not purport to be indicative of what would have occurred had the acquisition been consummated during the periods for which pro forma information is presented. From the year ended December 31, 2022 the results of the acquisition have been included in full year results.

Contracts with Customers

Contracts with Customers	12 Months Ended
	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Contracts with Customers	4. Contracts with Customers Disaggregation of Revenue The Company’s contracts contain both fixed price and cost reimbursable components. Contract types are based on the component that represents the majority of the contract. The following table presents revenue disaggregated by contract type (in thousands): December 31, December 31, December 31, Fixed-price $ 2,844,719 $ 1,810,499 $ 1,138,482 Time-and-Materials 1,419,168 1,352,871 1,166,548 Cost-plus 2,486,689 2,279,379 1,890,242 Total $ 6,750,576 $ 5,442,749 $ 4,195,272 Refer to “Note 20— Segments Information ” for the Company’s revenues by business lines. Contract Assets and Contract Liabilities Contract assets and contract liabilities balances at December 31, 2024 and December 31, 2023 were as follows (in thousands): December 31, 2024 December 31, 2023 $ change % change Contract assets $ 741,504 $ 757,515 $ ( 16,011 ) - 2.1 % Contract liabilities 289,799 301,107 ( 11,308 ) - 3.8 % Net contract assets (liabilities) (1) $ 451,705 $ 456,408 $ ( 4,703 ) - 1.0 % (1) Total contract retentions included in net contract assets (liabilities) were $ 89.8 million as of December 31, 2024, of which $ 35.9 million are not expected to be paid in 2025. Total contract retentions included in net contract assets (liabilities) were $ 73.8 million as of December 31, 2023. Contract assets at December 31, 2024 and December 31, 2023 include approximately $ 70.7 million and $ 109.5 million, respectively, related to net claim recovery estimates. For the year ended December 31, 2024 there was a $ 21.6 million loss recognized related to the collectability of claims. For the year ended December 31, 2023 , there were no material losses recognized related to the collectability of claims. During the years ended December 31, 2024 and December 31, 2023, the Company recognized revenue of approximately $ 190.3 million and $ 126.0 million, respectively, that was included in the corresponding contract liability balance at December 31, 2023 and December 31, 2022 , respectively. Certain changes in contract assets and contract liabilities consisted of the following: December 31, 2024 December 31, 2023 Acquired contract assets $ 19,858 $ 2,715 Acquired contract liabilities 4,446 3,155 There was no significant impairment of contract assets recognized during the years ended December 31, 2024 and December 31, 2023. Revisions in estimates, such as changes in estimated claims or incentives, related to performance obligations partially satisfied in previous periods that individually had an impact of $ 5 million or more on revenue resulted in the following changes in revenue. 2024 2023 2022 Revenue impact, net $ ( 55,952 ) $ 5,428 $ - Certain financial statement impacts from revisions in estimates were as follows (in thousands): December 31, 2024 December 31, 2023 December 31, 2022 Operating income (loss) $ ( 62,298 ) $ 35,297 $ — Net income (loss) ( 47,651 ) 26,261 — Diluted earnings (loss) per share $ ( 0.42 ) $ 0.23 $ - The amounts for 2024, in the table above, include the impact from a contract in the Critical Infrastructure segment related to a change in estimate increasing direct costs of contracts by $ 6.3 million. The amounts for 2023, in the table above, include the impact from contracts in the Critical Infrastructure segment related to a change in estimate increasing direct costs of contracts by $ 8.0 million related to net write-downs and a decrease in direct costs of contracts of $ 37.9 million related to a legal matter. These impacts do not include the operating income impacts disclosed below in "Note 16— Investments in and Advances to Joint Ventures. " Accounts Receivable, Net Accounts receivable, net consisted of the following as of December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Billed $ 712,046 $ 646,375 Unbilled 392,236 273,215 Total accounts receivable, gross 1,104,282 919,590 Allowance for doubtful accounts ( 3,886 ) ( 3,952 ) Total accounts receivable, net $ 1,100,396 $ 915,638 Billed accounts receivable represents amounts billed to clients that have not been collected. Unbilled accounts receivable represents amounts where the Company has a present contractual right to bill but an invoice has not been issued to the customer at the period-end date. Receivables from contracts with the U.S. federal government and its agencies were 23 % and 18 % as of December 31, 2024 and December 31, 2023, respectively. The allowance for doubtful accounts was determined based on consideration of trends in actual and forecasted credit quality of clients, including delinquency and payment history, type of client, such as a government agency or commercial sector client, and general economic conditions and particular industry conditions that may affect a client’s ability to pay. Transaction Price Allocated to the Remaining Unsatisfied Performance Obligations The Company’s remaining unsatisfied performance obligations (“RUPO”) as of December 31, 2024 represent a measure of the total dollar value of work to be performed on contracts awarded and in progress. The Company had $ 6.7 billion in RUPO as of December 31, 2024. RUPO will increase with awards of new contracts and decrease as the Company performs work and recognizes revenue on existing contracts. Projects are included within RUPO at such time the project is awarded and agreement on contract terms has been reached. The difference between RUPO and backlog relates to unexercised option years that are included within backlog and the value of Indefinite Delivery/Indefinite Quantity (“IDIQ”) contracts included in backlog for which task orders have not been issued. RUPO is comprised of: (a) original transaction price, (b) change orders for which written confirmations from our customers have been received, (c) pending change orders for which the Company expects to receive confirmatrions in the ordinary course of business, and (d) claim amounts that the Company has made against customers for which it has determined that it has a legal basis under existing contractual arrangements and a significant reversal of revenue is not probable, less revenue recognized to-date. The Company expects to satisfy its RUPO as of December 31, 2024 over the following periods (in thousands): Period RUPO Will Be Satisfied Within One Year Within One to Two Years Thereafter Federal Solutions $ 1,815,751 $ 439,216 $ 142,994 Critical Infrastructure 2,062,055 1,099,765 1,174,217 Total $ 3,877,806 $ 1,538,981 $ 1,317,211

Leases

Leases	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Leases	5. Leases The Company has operating and finance leases for corporate and project office spaces, vehicles, heavy machinery and office equipment. Our leases have remaining lease terms of one year to eleven years , some of which may include options to extend the leases for up to five years , and some of which may include options to terminate the leases after the third year. The components of lease costs for the years ended December 31, 2024 and December 31, 2023 are as follows (in thousands): 2024 2023 Operating lease cost $ 64,858 $ 67,181 Short-term lease cost 17,114 13,782 Amortization of right-of-use assets 3,549 2,699 Interest on lease liabilities 434 273 Sublease income ( 4,289 ) ( 4,718 ) Total lease cost $ 81,666 $ 79,217 Supplemental cash flow information related to leases for the years ended December 31, 2024 and December 31, 2023 is as follows (in thousands): 2024 2023 Operating cash flows for operating leases $ 67,696 $ 71,432 Operating cash flows for finance leases 434 273 Financing cash flows for finance leases 3,376 2,618 Right-of-use assets obtained in exchange for new 36,583 62,856 Right-of-use assets obtained in exchange for new $ 4,220 $ 6,456 Supplemental balance sheet and other information related to leases as of December 31, 2024 and December 31, 2023 is as follows (in thousands): 2024 2023 Operating Leases: Right-of-use assets $ 153,048 $ 159,211 Lease liabilities: Current $ 52,725 $ 58,556 Long-term 114,386 117,505 Total operating lease liabilities $ 167,111 $ 176,061 Finance Leases: Other noncurrent assets $ 9,864 $ 7,779 Accrued expenses and other current liabilities $ 3,645 $ 2,682 Other long-term liabilities $ 6,441 $ 5,129 Weighted Average Remaining Lease Term: Operating leases 3.9 Years 3.9 Years Finance leases 2.8 Years 3.1 years Weighted Average Discount Rate: Operating leases 4.5 % 4.2 % Finance leases 5.0 % 4.6 % As of December 31, 2024 , the Company has no additional operating leases that have not yet commenced. A maturity analysis of the future undiscounted cash flows associated with the Company’s operating and finance lease liabilities as of December 31, 2024 is as follows (in thousands): Operating Finance 2025 $ 59,839 $ 4,217 2026 42,669 3,492 2027 29,744 2,236 2028 24,383 933 2029 18,341 92 Thereafter 7,682 - Total lease payments 182,658 10,970 Less: imputed interest ( 15,547 ) ( 884 ) Total present value of lease liabilities $ 167,111 $ 10,086 Rental expense for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 was $ 82.0 million , $ 81.0 million and $ 81.0 million , respectively, and is recorded in “Selling, general and administrative expenses” in the consolidated statements of income.

Employee Stock Purchase and Equ

Employee Stock Purchase and Equity-Based Compensation Plans	12 Months Ended
	Dec. 31, 2024
Share-Based Payment Arrangement [Abstract]
Equity-Based Compensation	6. Employee Stock Purchase and Equity-Based Compensation Plans Equity Compensation Plan Information The following table provides information as of December 31, 2024 regarding compensation plans under which our equity securities are authorized for issuance. Plan Category Number of Securities to be Issued upon Exercise of Outstanding Options, Warrants and Rights Weighted-Average Exercise Price of Outstanding Options, Warrants and Rights Number of Securities Remaining Available for Future Issuance under Equity Compensation Plans (Excluding Securities Reflected in Column (a)) Equity compensation plans approved by security holders (1) - - 1,367,785 (2) Equity compensation plans not approved by security holders 1,883,018 (3) - 7,651,085 (4) Total 1,883,018 - 9,018,870 (1) Consists of the 2020 Employee Stock Purchase Plan. (2) Amount represents 1,367,785 shares remaining available for future issuance under the 2020 Employee Stock Purchase Plan (of which 47,860 shares were purchased pursuant to the offering period that ended on December 31, 2024). (3) Amount represents the sum of 1,883,018 shares of common stock subject to outstanding RSU and PSU awards under the 2019 Incentive Plan (with PSU awards reflected at “target” levels), (4) Amount represents 7,651,085 shares remaining available for future issuance under the 2019 Incentive Plan. Employee Stock Purchase Plan The Parsons Corporation Employee Stock Purchase Plan (“ESPP”) was adopted effective March 1, 2020. Under the ESPP, eligible employees who elect to participate are granted the right to purchase shares of Parsons common stock at a discount of 5 % of the market value on the last trading day of the offering period. The following table presents stock issuance activity for the years ended December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Purchase price paid for shares sold $ 7,935 $ 6,059 Number of shares sold 96 117 The average purchase price for the year ended December 31, 2024 and December 31, 2023 was $ 82.66 and $ 51.94 per share, respectively. Equity-Based Compensation Plans The Company issues stock-based awards through the Incentive Award Plan. The compensation expense for these awards is recorded in “Selling, general and administrative expenses” in the Company’s consolidated financial statements. Stock-based compensation expense was $ 52.6 million, $ 27.5 million, and $ 20.0 million for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 , respectively, net of recognized tax benefits of $ 8.9 million, $ 8.6 million, and $ 4.4 million for 2024, 2023 and 2022, respectively. The tax benefit realized related to awards vested during 2024, 2023, and 2022 was $ 12.0 million, $ 4.3 million, and $ 2.7 million, respectively. We recognize forfeitures as they occur. At December 31, 2024 , the amount of compensation cost relating to non-vested awards not yet recognized in the consolidated financial statements is $ 51.3 million. The majority of these unrecognized compensation costs will be recognized by the third quarter of fiscal 2026. Restricted Stock Units Restricted Stock Units awards are issued under the Incentive Award Plan and are settled by the issuance of the Company’s common stock. Outstanding awards have been granted based on either service or service and performance conditions. Awards vest over three-year periods, either annually or cliff. Expense is recognized on an accelerated basis for awards with service conditions only and on a straight-line basis for awards that include performance conditions. Expense recognition of awards with performance criteria are subject to the probability of meeting the performance conditions and adjusted for the number of shares expected to be earned. Compensation cost for awards with performance conditions are trued-up at each reporting period for changes in the expected shares pro-rated for the portion of the requisite service period rendered. The following table presents the number of shares of restricted stock units granted (at target shares for awards with performance conditions) for the years ended December 31, 2024, December 31, 2023 and December 31, 2022: December 31, December 31, December 31, Restricted Stock Units (service condition) 346,483 616,337 666,184 Restricted Stock Units (service and performance condition) 296,513 452,179 402,436 The number of units granted for awards with performance conditions in the above table is based on performance at the target amount. The number of shares ultimately issued, which could be greater or less than target, will be based on achieving specific performance conditions related to the awards. During the years ended December 31, 2024 and December 31, 2023, certain restricted stock unit grants with performance conditions vested with performance different from the target share amounts. As a result, 99,280 and 97,551 additional shares, respectively were granted and vested. The following table presents the number and weighted average grant-date fair value of restricted stock units (at target shares for awards with performance conditions) for the years ended December 31, 2024, December 31, 2023 and December 31, 2022: Number of Units Weighted Average Grant-Date Fair Value Outstanding at December 31, 2021 1,359,243 $ 36.75 Granted 1,068,620 37.42 Vested ( 497,200 ) 35.86 Forfeited ( 309,508 ) 36.28 Outstanding at December 31, 2022 1,621,155 37.49 Granted 1,068,516 48.96 Vested ( 372,962 ) 37.56 Forfeited ( 223,373 ) 39.90 Outstanding at December 31, 2023 2,093,336 43.11 Granted 642,996 79.71 Vested ( 697,956 ) 37.83 Forfeited ( 155,358 ) 45.33 Outstanding at December 31, 2024 1,883,018 $ 57.35 For the year ended December 31, 2024 , 778,167 shares of restricted stock units were issued, and 272,284 shares of common stock related to employee statutory income tax withholding were retired. For the year ended December 31, 2023 , 484,988 shares of restricted stock units were issued, and 159,281 shares of common stock related to employee statutory income tax withholding were retired. For the year ended December 31, 2022 , 458,952 shares of restricted stock units were issued, and 160,212 shares of common stock related to employee statutory income tax withholding were retired. The following table presents the number of shares of restricted stock outstanding (at target shares for awards with performance conditions) at December 31, 2024, December 31, 2023 and December 31, 2022: December 31, December 31, December 31, Restricted Stock Units (service condition) 911,908 1,085,203 817,278 Restricted Stock Units (service and performance condition) 971,110 1,008,133 803,877

Goodwill

Goodwill	12 Months Ended
	Dec. 31, 2024
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	7. Goodwill The following table summarizes the changes in the carrying value of goodwill by reporting segment for the years ended December 31, 2024 and December 31, 2023 (in thousands): December 31, Acquisitions Foreign December 31, Federal Solutions $ 1,686,901 $ 119,663 $ - $ 1,806,564 Critical Infrastructure 105,764 174,585 ( 4,233 ) 276,116 Total $ 1,792,665 $ 294,248 $ ( 4,233 ) $ 2,082,680 December 31, Acquisitions Foreign December 31, Federal Solutions $ 1,591,563 $ 95,338 $ - $ 1,686,901 Critical Infrastructure 70,287 34,261 1,216 105,764 Total $ 1,661,850 $ 129,599 $ 1,216 $ 1,792,665 For the years ended December 31, 2024 and December 31, 2023 , the Company performed a quantitative impairment analysis for all reporting units. It was determined that the fair value of all reporting units exceeded their carrying values. No goodwill impairments were identified for the three years ended December 31, 2024, December 31, 2023 and December 31, 2022 .

Intangible Assets

Intangible Assets	12 Months Ended
	Dec. 31, 2024
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	8. Intangible Assets The gross amount and accumulated amortization of acquired identifiable intangible assets included in “Intangible assets, net” on the consolidated balance sheets were as follows (in thousands except for years): December 31, 2024 December 31, 2023 Weighted Gross Accumulated Net Gross Accumulated Net Amortization (in years) Backlog $ 142,100 $ ( 51,322 ) $ 90,778 $ 130,000 $ ( 45,964 ) $ 84,036 4.5 Customer relationships 372,930 ( 139,568 ) 233,362 297,120 ( 124,194 ) 172,926 11.6 Leases - - - 120 ( 106 ) 14 - Developed technology 23,200 ( 7,458 ) 15,742 31,600 ( 15,823 ) 15,777 4.6 Trade name 1,500 ( 367 ) 1,133 1,000 ( 417 ) 583 1.0 Non-compete agreements 8,300 ( 1,203 ) 7,097 1,500 ( 1,097 ) 403 3.0 In process research and development 1,800 - 1,800 1,800 - 1,800 n/a Other intangibles 25 - 25 375 ( 348 ) 27 n/a Total intangible assets $ 549,855 $ ( 199,918 ) $ 349,937 $ 463,515 $ ( 187,949 ) $ 275,566 The aggregate amortization expense of intangible assets was $ 55.6 million , $ 76.6 million, and $ 78.2 million for the years ended December 31, 2024, December 31, 2023 and December 31, 2022, respectively. Estimated amortization expense in each of the next five years and beyond is as follows (in thousands): December 31, 2024 2025 $ 64,871 2026 57,313 2027 50,759 2028 36,871 2029 22,659 Thereafter 115,639 Total $ 348,112

Property and Equipment, Net

Property and Equipment, Net	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Property and Equipment, Net	9. Property and Equipment, Net Property and equipment consisted of the following at December 31, 2024 and December 31, 2023 (in thousands): December 31, 2024 December 31, 2023 Useful life Buildings and leasehold improvements $ 103,945 $ 102,372 1 - 15 Furniture and equipment 84,720 84,244 3 - 10 Computer systems and equipment 172,437 168,926 3 - 10 Construction equipment 6,463 6,173 5 - 7 Construction in progress 30,342 21,030 397,907 382,745 Accumulated depreciation ( 286,332 ) ( 283,788 ) Property and equipment, net $ 111,575 $ 98,957 Depreciation expense of $ 37.4 million , $ 39.1 million, and $ 39.0 million was recorded for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 , respectively.

Accrued Expenses and Other Curr

Accrued Expenses and Other Current Liabilities	12 Months Ended
	Dec. 31, 2024
Payables and Accruals [Abstract]
Accrued Expenses and Other Current Liabilities	10. Accrued Expenses and Other Current Liabilities Accrued expenses and other current liabilities consisted of the following at December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Salaries and wages $ 119,122 $ 102,779 Employee benefits 371,435 342,707 Self-insurance liability 17,723 24,193 Project cost accruals 307,200 254,070 Other accrued expenses 78,945 77,674 Total accrued expenses and other current liabilities $ 894,425 $ 801,423

Debt and Credit Facilities

Debt and Credit Facilities	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Debt and Credit Facilities	11. Debt and Credit Facilities Debt consisted of the following at December 31, 2024 and December 31, 2023 (in thousands): December 31, 2024 December 31, 2023 Short-Term Debt: Delayed draw term loan $ 350,000 $ - Convertible senior notes due 2025 113,405 - Total Short-Term Debt 463,405 - Long-Term Debt: Delayed draw term loan - 350,000 Convertible senior notes due 2025 - 400,000 Convertible senior notes due 2029 800,000 - Revolving credit facility - - Debt issuance costs ( 15,904 ) ( 4,037 ) Total Long-Term Debt 784,096 745,963 Total Debt $ 1,247,501 $ 745,963 Delayed Draw Term Loan In September 2022 , the Company entered into a $ 350 million unsecured Delayed Draw Term Loan with an increase option of up to $ 150 million (the “2022 Delayed Draw Term Loan”). The 2022 Delayed Draw Term Loan may be borrowed in a single draw during the period from and including the Closing Date to the earlier to occur of (a) the date of termination of the 2022 Delayed Draw Term Loan by the Company pursuant to the terms of the 2022 Delayed Draw Term Loan Agreement and (b) six (6) months following the Closing Date. Proceeds of the 2022 Delayed Draw Term Loan Agreement may be used (a) to pay off in full, or partially payoff, the Company’s existing Senior Notes, (b) to prepay revolving loans outstanding under the Revolving Credit Agreement (as defined below), or (c) for working capital, capital expenditures and other lawful corporate purposes. The Company drew $ 350.0 million from the 2022 Delayed Draw Term Loan in November 2022. The Company incurred $ 0.9 million of debt issuance costs in connection with the delayed draw term loan as of December 31, 2022. These costs are presented as a direct deduction from the debt on the face of the balance sheet. Interest expense related to the Delayed Draw Term Loan was $ 23.1 million, $ 22.4 million and $ 3.3 million for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 respectively. The amortization of debt issuance costs and interest expense is recorded in “Interest expense” on the consolidated statements of income. As of December 31, 2024 and December 31, 2023 , there was $ 350.0 million outstanding under the Delayed Draw Term Loan. The 2022 Delayed Draw Term Loan has a three-year maturity and permits the Company to borrow in U.S. dollars. The 2022 Delayed Draw Term Loan does not require any amortization payments by the Company. Depending on the Company’s consolidated leverage ratio (or debt rating after such time as the Company has such rating), borrowings under the 2022 Delayed Draw Term Loan Agreement will bear interest at either an adjusted Term SOFR benchmark rate plus a margin between 0.875 % and 1.500 % or a base rate plus a margin of between 0 % and 0.500 % and will initially bear interest at the middle of this range. The Company will pay a ticking fee on unused term loan commitments at a rate of 0.175 % commencing with the date that is ninety (90) days after the Closing Date. Amounts outstanding under the 2022 Delayed Draw Term Loan Agreement may be prepaid at the option of the Company without premium or penalty, subject to customary breakage fees in connection with the prepayment of benchmark rate loans. The interest rates on December 31, 2024 and December 31, 2023 were 5.6 % and 6.6 %, respectively. Convertible Senior Notes due 2025 In August 2020, the Company issued an aggregate $ 400.0 million of 0.25 % Convertible Senior Notes due 2025, including the exercise of a $ 50.0 million initial purchasers’ option. The Company received proceeds from the issuance and sale of the Convertible Senior Notes of $ 389.7 million, net of $ 10.3 million of transaction fees and other third-party offering expenses. The Convertible Senior Notes accrue interest at a rate of 0.25 % per annum, payable semi-annually on February 15 and August 15 of each year beginning on February 15, 2021 , and will mature on August 15, 2025 , unless earlier repurchased, redeemed or converted. The Convertible Senior Notes are the Company’s senior unsecured obligations and will rank senior in right of payment to any of the Company’s indebtedness that is expressly subordinated in right of payment to the Notes; equal in right of payment to any of the Company’s unsecured indebtedness that is not so subordinated; effectively junior in right of payment to any of the Company’s secured indebtedness, to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness and other liabilities (including trade payables) of the Company’s subsidiaries. Each $ 1,000 of principal of the Notes will initially be convertible into 22.2913 shares of our common stock, which is equivalent to an initial conversion price of $ 44.86 per share, subject to adjustment upon the occurrence of specified events. On or after March 15, 2025 until the close of business on the second scheduled trading day immediately preceding the maturity date of the Convertible Senior Notes, holders may convert all or a portion of their Convertible Senior Notes, regardless of the conditions below. Prior to the close of business on the business day immediately preceding March 15, 2025, the Notes will be convertible at the option of the holders thereof only under the following circumstances: • during any calendar quarter commencing after the calendar quarter ending on December 31, 2020, if the last reported sale price of the Company’s common stock for at least 20 trading days, whether or not consecutive, during a period of 30 consecutive trading days ending on, and including the last trading day of the immediately preceding calendar quarter, is greater than or equal to 130 % of the conversion price on each applicable trading day; • during the five business day period after any five consecutive trading day period in which, for each trading day of that period, the trading price per $ 1,000 principal amount of Convertible Senior Notes for such trading day was less than 98 % of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; • if the Company calls such Convertible Senior Notes for redemption; or • upon the occurrence of specified corporate events described in the Indenture. The Company may redeem all or any portion of the Convertible Senior Notes for cash, at its option, on or after August 21, 2023 and before the 51 st scheduled trading day immediately before the maturity date at a redemption price equal to 100 % of the principal amount of the Notes to be redeemed, plus accrued and unpaid interest, but only if the last reported sale price per share of the Company’s common stock exceeds 130 % of the conversion price for a specified period of time. In addition, calling any Convertible Senior Note for redemption will constitute a Make-Whole Fundamental Change with respect to that Convertible Senior Note, in which case the conversion rate applicable to the conversion of that Convertible Senior Note will be increased in certain circumstances if it is converted after it is called for redemption. Upon the occurrence of a fundamental change prior to the maturity date of the Convertible Senior Notes, holders of the Convertible Senior Notes may require the Company to repurchase all or a portion of the Convertible Senior Notes for cash at a price equal to 100 % of the principal amount of the Convertible Senior Notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date. Upon conversion, the Company may settle the Convertible Senior Notes for cash, shares of the Company’s common stock, or a combination thereof, at the Company’s option. If the Company satisfies its conversion obligation solely in cash or through payment and delivery of a combination of cash and shares of the Company’s common stock, the amount of cash and shares of common stock due upon conversion will be based on a daily conversion value calculated on a proportionate basis for each trading day in a 50-trading day observation period. The Company recognized interest expense of $ 3.9 million, $ 3.1 million and $ 3.0 million for the years ended December 31, 2024. December 31, 2023 and December 31, 2022, respectively. As of December 31, 2024 and December 31, 2023 the net carrying value of the Convertible Senior Notes due 2025 were $ 113.4 million and $ 396.5 million, respectively. See the discussion of the partial repurchase of Convertible Senior Notes due 2025 and the unwind of the related note hedge and warrants below. Note Hedge and Warrant - Convertible Senior Notes due 2025 In connection with the sale of the Convertible Senior Notes, the Company purchased a bond hedge designed to mitigate the potential dilution from the conversion of the Convertible Senior Notes. Under the five-year term of the bond hedge, upon a conversion of the bonds, the Company will receive the number of shares of common stock equal to the remaining common stock deliverable upon conversion of the Convertible Senior Notes if the conversion value exceeds the principal amount of the Notes. The aggregate number of shares that the Company could be obligated to issue upon conversion of the Convertible Senior Notes is approximately 8.9 million shares. The cost of the convertible note hedge transactions was $ 55.0 million. The cost of the convertible note hedge was partially offset by the Company’s sale of warrants to acquire approximately 8.9 million shares of the Company’s common stock. The warrants were initially exercisable at a price of at least $ 66.46 per share and are subject to customary adjustments upon the occurrence of certain events, such as the payment of dividends. The Company received $ 13.8 million in cash proceeds from the sales of these warrants. The bond hedge and warrant transactions effectively increased the conversion price associated with the Convertible Senior Notes during the term of these transactions from 35 %, or $ 44.86 , to 100 %, or $ 66.46 , at their issuance, thereby reducing the dilutive economic effect to shareholders upon actual conversion. The bond hedges and warrants are indexed to, and potentially settled in, shares of the Company’s common stock. The net cost of $ 41.2 million for the purchase of the bond hedges and sale of the warrants was recorded as a reduction to additional paid-in capital in the consolidated balance sheets. At issuance, the Company recorded a deferred tax liability of $ 16.2 million related to the Convertible Senior Notes debt discount and the capitalized debt issuance costs. The Company also recorded a deferred tax asset of $ 16.5 million related to the convertible note hedge transactions and the tax basis of the capitalized debt issuance costs through additional paid-in capital. The deferred tax liability and deferred tax asset were included net in “Deferred tax assets” on the consolidated balance sheets. Upon adoption of ASU 2020-06, the Company reversed the deferred tax liability of $ 13.9 million that the Company had recorded at issuance related to the Convertible Senior Note debt discount and recorded an additional deferred tax liability of $ 0.4 million related to the capitalized debt issuance costs. In addition, the Company recorded a $ 0.9 million adjustment to the deferred tax asset through retained earnings related to the tax effect of book accretion recorded in 2020 and reversed upon adoption. Convertible Senior Notes due 2029 In February 2024, the Company issued an aggregate $ 800.0 million of 2.625 % Convertible Senior Notes due 2029 (the “2029 Convertible Notes”), including the exercise of a $ 100.0 million initial purchasers’ option in full. The Company received proceeds from the issuance and sale of the 2029 Convertible Notes of $ 781.1 million, net of $ 18.9 million of transaction fees and other third-party offering expenses. The 2029 Convertible Notes accrue interest at a rate of 2.625 % per annum, payable semi-annually on March 1 and September 1 of each year beginning on September 1, 2024 , and will mature on March 1, 2029 , unless earlier repurchased, redeemed or converted. The 2029 Convertible Notes are the Company’s senior unsecured obligations and will rank senior in right of payment to any of the Company’s indebtedness that is expressly subordinated in right of payment to the 2029 Convertible Notes; equal in right of payment to any of the Company’s unsecured indebtedness that is not so subordinated; effectively junior in right of payment to any of the Company’s secured indebtedness, including borrowings under the Company’s revolving credit facility and delayed draw term loan credit facility, to the extent of the value of the assets securing such indebtedness; and structurally junior to all indebtedness and other liabilities (including trade payables) of the Company’s subsidiaries. Each $ 1,000 of principal of the 2029 Convertible Notes will initially be convertible into 10.6256 shares of our common stock, which is equivalent to an initial conversion price of approximately $ 94.11 per share, subject to adjustment upon the occurrence of specified events. On or after October 1, 2028 until the close of business on the second scheduled trading day immediately preceding the maturity date of the 2029 Convertible Notes, holders may convert all or a portion of their 2029 Convertible Notes, regardless of the conditions below. Prior to the close of business on the business day immediately preceding October 1, 2028, the 2029 Convertible Notes will be convertible at the option of the holders thereof only under the following circumstances: • during any calendar quarter commencing after the calendar quarter ending on June 30, 2024, if the last reported sale price of the Company’s common stock for at least 20 trading days, whether or not consecutive, during a period of 30 consecutive trading days ending on, and including the last trading day of the immediately preceding calendar quarter, is greater than or equal to 130 % of the conversion price on each applicable trading day; • during the five business day period after any ten consecutive trading day period in which, for each trading day of that period, the trading price per $ 1,000 principal amount of 2029 Convertible Notes for such trading day was less than 98 % of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day; • if the Company calls such 2029 Convertible Notes for redemption; or • upon the occurrence of specified corporate events described in the Indenture. The Company may redeem all or any portion of the 2029 Convertible Notes for cash, at its option, on or after March 8, 2027 and before the 51 st scheduled trading day immediately before the maturity date at a redemption price equal to 100 % of the principal amount of the 2029 Convertible Notes to be redeemed, plus accrued and unpaid interest, but only if the last reported sale price per share of the Company’s common stock exceeds 130 % of the conversion price for a specified period of time. In addition, calling any 2029 Convertible Notes for redemption will constitute a Make-Whole Fundamental Change with respect to that 2029 Convertible Note, in which case the conversion rate applicable to the conversion of that 2029 Convertible Notes will be increased in certain circumstances if it is converted after it is called for redemption. Upon the occurrence of a fundamental change prior to the maturity date of the 2029 Convertible Notes, holders of the 2029 Convertible Notes may require the Company to repurchase all or a portion of the 2029 Convertible Notes for cash at a price equal to 100 % of the principal amount of the 2029 Convertible Notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date. Upon conversion, the Company will settle the principal amount of the 2029 Convertible Notes converted in cash and will settle the remainder of the consideration owed upon conversion in cash, shares of the Company’s common stock, or a combination thereof, at the Company’s option, with such amount of cash and, if applicable, shares of common stock due upon conversion based on a daily conversion value calculated on a proportionate basis for each trading day in a 50-trading day observation period. The Company recognized interest expense with respect to the 2029 Convertible Notes of $ 21.3 million for the year ended December 31, 2024. As of December 31, 2024 , the net carrying value of the 2029 Convertible Notes due 2029 was $ 784.3 million. Capped Call Transactions - Convertible Senior Notes due 2029 In February 2024, in connection with the offering of the 2029 Convertible Notes, the Company entered into capped call transactions (the “Capped Call Transactions”) with certain financial institutions. The Capped Call Transactions are expected generally to reduce the potential dilution to the Company’s common stock upon any conversion of the Convertible Senior Notes due 2029 and/or offset any cash payments the Company is required to make in excess of the principal amount of any converted Convertible Senior Notes due 2029, as the case may be. If, however, the market price per share of the Company’s common stock, as measured under the terms of the Capped Call Transactions, exceeds the cap price of the Capped Call Transactions, there would nevertheless be dilution and/or there would not be an offset of such cash payments, in each case, to the extent that such market price exceeds the cap price of the Capped Call Transactions. The cap price of the Capped Call Transactions is initially $ 131.7575 per share, which represents a premium of 75 % over the last reported sale price of the Company’s common stock of $ 75.29 per share on the New York Stock Exchange on February 21, 2024, and is subject to certain adjustments under the terms of the Capped Call Transactions. The cost of $ 88.4 million for the Capped Call Transactions was recorded as a reduction to additional paid-in capital in the consolidated balance sheets. At issuance, the Company recorded a deferred tax asset of $ 22.3 million related to the Capped Call Transactions costs through additional paid-in capital. The deferred tax asset was included in Deferred tax assets in the consolidated balance sheets. Convertible Senior Notes due 2025 Partial Repurchase and Note Hedge and Warrants Partial Unwind In connection with the issuance of the Convertible Senior Notes due 2029, during the first quarter of 2024, we used $ 391.8 million of the net proceeds to purchase approximately $ 228.1 million aggregate principal amount of our Convertible Senior Notes due 2025 concurrently with the offering in separate and individually negotiated transactions. In addition, we used $ 103.8 million to settle the repurchase of approximately $ 56.5 million aggregate principal amount of our Convertible Senior Notes due 2025 in a separately negotiated transaction that settled in March 2024. We also received approximately $ 90.6 million in cash from the note hedge counterparties for the partial termination of the existing bond hedge relating to the Convertible Senior Notes due 2025 repurchased, net of our obligations to the counterparties in connection with the partial termination of the related warrant transactions. The tax effect of $ 46.2 million from the partial unwind of the existing bond hedge was recognized as a reduction in additional paid-in capital in the consolidated balance sheets. The income tax payable was included in Income taxes payable in the consolidated balance sheets. The partial repurchase, during the year ended December 31, 2024 , resulted in a $ 18.4 million repurchase loss 1 and a $ 3.2 million charge to interest expense for the acceleration of the amortization of debt issuance costs associated with the 0.25 % Convertible Senior Notes due 2025. The tax effect of the repurchase loss, excluding the interest expense, was recognized as a discrete event during the year with a tax benefit of $ 4.3 million recognized in the income statement. 1 During the first quarter of 2024, prior to the early adoption of ASU 2024-04, the Company recorded a $ 211.0 million loss on debt extinguishment associated with the 0.25 % Convertible Senior Notes due 2025. The tax effect of the debt extinguishment, excluding the interest expense, was recognized as a discrete event to the quarter giving rise to an increase in the effective tax rate and tax benefit of $ 49.9 million recognized in the income statement. Please see "Note 2—Summary of Significant Accounting Policies—New Accounting Pronouncements" for a discussion of the Company's adoption of ASU 2024-04. The extinguishment charge and related income tax impacts were reversed from the Company's consolidated financial statements and recorded as a convertible debt repurchase loss as described above. Revolving Credit Facility In June 2021 , the Company entered into a $ 650 million unsecured revolving credit facility (the “Credit Agreement”). The Company incurred $ 1.9 million of costs in connection with this Credit Agreement. The 2021 Credit Agreement replaced an existing Fifth Amended and Restated Credit Agreement dated as of November 15, 2017. Under the new agreement, the Company’s revolving credit facility was increased from $ 550 million to $ 650 million. The credit facility has a five-year maturity, which may be extended up to two times for periods determined by the Company and the applicable extending lenders, and permits the Company to borrow in U.S. dollars, certain specified foreign currencies, and each other currency that may be approved in accordance with the 2021 Facility. The borrowings under the Credit Agreement bear interest at either a eurocurrency rate plus a margin between 1.0 % and 1.625 % or a base rate (as defined in the Credit Agreement) plus a margin of between 0 % and 0.625 %. The rates on December 31, 2024 and December 31, 2023 were 5.7 % and 6.7 %, respectively. Borrowings under this Credit Agreement are guaranteed by certain Company operating subsidiaries. Letters of credit commitments outstanding under this agreement aggregated approximately $ 43.0 million and $ 43.8 million at December 31, 2024 and December 31, 2023 , respectively, which reduced borrowing limits available to the Company. Interest expense related to the Credit Agreement was $ 0.7 million, $ 3.9 million and $ 4.3 million, for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 , respectively. There were no loan amounts outstanding under the Credit Agreement at December 31, 2024 and December 31, 2023. The Credit Agreement includes various covenants, including restrictions on indebtedness, liens, acquisitions, investments or dispositions, payment of dividends and maintenance of certain financial ratios and conditions. The Company was in compliance with these covenants at December 31, 2024 and December 31, 2023. Letters of Credit The Company also has in place several secondary bank credit lines for issuing letters of credit, principally for foreign contracts, to support performance and completion guarantees. Letters of credit commitments outstanding under these bank lines aggregated approximately $ 328.4 million and $ 320.7 million at December 31, 2024 and December 31, 2023 , respectively.

Other Long-term Liabilities

Other Long-term Liabilities	12 Months Ended
	Dec. 31, 2024
Other Liabilities Disclosure [Abstract]
Other Long-term Liabilities	12. Other Long-term Liabilities Other long-term liabilities consisted of the following at December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Self-insurance liability $ 58,878 $ 81,795 Reserve for uncertain tax positions 22,985 22,815 Finance lease obligations 6,441 5,129 Other long-term liabilities 8,182 10,556 Total other long-term liabilities $ 96,486 $ 120,295 Refer to “Note 13— Income Taxes ” for further discussion of the Company’s reconciliation of the beginning and ending balances of uncertain tax positions.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Income Taxes	13. Income Taxes The following table presents the components of our income from operations before income taxes (in thousands): 2024 2023 2022 United States earnings $ 256,210 $ 179,522 $ 77,110 Foreign earnings 111,441 84,531 89,112 $ 367,651 $ 264,053 $ 166,222 The income tax expense (benefit) attributable to income from operations for the years ended December 31, 2024, December 31, 2023, and December 31, 2022 consists of the following (in thousands): 2024 2023 2022 Current Federal $ 37,713 $ 37,699 $ 21,323 State 13,441 13,340 9,946 Foreign 19,731 14,013 9,232 Total current income tax expense 70,885 65,052 40,501 Deferred Federal 1,397 ( 5,974 ) ( 2,902 ) State 3,941 ( 590 ) ( 623 ) Foreign 763 ( 2,350 ) 2,681 Total deferred tax benefit 6,101 ( 8,914 ) ( 844 ) Total income tax expense $ 76,986 $ 56,138 $ 39,657 Income tax expense (benefit) was different from the amount computed by applying the United States federal statutory rate to pre-tax income from continuing operations as a result of the following (in thousands): 2024 2023 2022 Income before income tax expense $ 367,651 $ 264,053 $ 166,222 Tax at federal statutory tax rate 77,207 21.0 % 55,451 21.0 % 34,907 21.0 % State taxes, net of federal tax benefit 11,852 3.2 % 9,807 3.7 % 7,530 4.5 % Change in valuation allowance 11,111 3.0 % 5,773 2.2 % 1,363 0.8 % Change in uncertain tax positions 3,584 1.0 % 3,530 1.3 % 1,688 1.0 % Foreign tax rate differential ( 6,078 ) - 1.7 % ( 6,258 ) - 2.4 % ( 1,787 ) - 1.1 % Tax cost of foreign operations, net of credits 1,842 0.5 % 3,085 1.2 % 777 0.5 % Foreign-derived intangible income deduction ( 14,794 ) - 4.0 % ( 4,736 ) - 1.8 % ( 76 ) 0.0 % Noncontrolling interests ( 11,679 ) - 3.2 % ( 9,821 ) - 3.7 % ( 6,279 ) - 3.8 % Federal business credits ( 2,932 ) - 0.8 % ( 2,731 ) - 1.0 % ( 1,926 ) - 1.2 % Executive compensation 7,351 2.0 % 1,636 0.6 % 1,921 1.2 % Equity compensation ( 7,170 ) - 2.0 % ( 158 ) - 0.1 % 10 0.0 % Other, net 6,692 1.8 % 560 0.2 % 1,529 0.9 % Total income tax expense $ 76,986 20.9 % $ 56,138 21.3 % $ 39,657 23.9 % The effective tax rate in 2024 decreased to 20.9 % from 21.3 % in 2023. The change in the effective tax rate was due primarily to tax benefits related to increases in the foreign-derived intangible income (FDII) deduction and increased equity-based compensation deductions, partially offset by an increase in valuation allowance on NOLs and non-deductible executive compensation subject to Section 162(m). The effective tax rate in 2023 decreased to 21.3 % from 23.9 % in 2022. The change in the effective tax rate was due primarily to tax benefits related to increases in the foreign-derived intangible income (FDII) deduction and a change in jurisdictional mix of earnings, partially offset by an increase in valuation allowance on foreign tax credits originating from foreign withholding taxes. The effective tax rate for the year ended December 31, 2024 differs from the federal statutory tax rate of 21 % primarily due to state income taxes, valuation allowance and executive compensation subject to Section 162(m), offset by benefits related to untaxed income attributable to noncontrolling interests, earnings in lower tax jurisdictions, the FDII deduction, and equity-based compensation deductions. The effective tax rate for the year ended December 31, 2023 differs from the federal statutory tax rate primarily due to state income taxes, valuation allowance on foreign tax credit carryovers originating from foreign taxes, partially offset by benefits related to untaxed income attributable to noncontrolling interests, earnings in lower tax jurisdictions, the FDII deduction, and federal business tax credits. The effective tax rate for the year ended December 31, 2022 differs from the federal statutory tax rate primarily due to state income taxes and a recorded valuation allowance on foreign tax credit carryovers, partially offset by benefits related to income attributable to noncontrolling interests, earnings in lower tax jurisdictions and federal business tax credits. The components of deferred tax assets and liabilities consist of the following at December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Deferred tax assets Project and non-project reserves $ 23,184 $ 23,555 Employee compensation and benefits 76,944 69,726 Revenue and cost recognition 46,250 37,616 Insurance accruals 12,424 14,081 Net operating losses 17,640 8,663 Lease liabilities 42,572 44,626 Tax credit carryforwards 35,845 31,727 Other 17,432 3,285 Total deferred tax assets 272,291 233,279 Valuation allowance ( 45,318 ) ( 34,779 ) Total deferred tax assets 226,973 198,500 Deferred tax liabilities Intangible assets ( 57,361 ) ( 18,783 ) Right-of-use assets ( 38,605 ) ( 40,131 ) Profit remittance tax ( 6,842 ) ( 5,822 ) Other ( 1,758 ) ( 3,378 ) Total deferred tax liabilities ( 104,566 ) ( 68,114 ) Net deferred tax asset $ 122,407 $ 130,386 The Company is not asserting that any of the earnings of the foreign subsidiaries will be permanently reinvested. Therefore, the Company has recorded a deferred tax liability for the undistributed earnings net of applicable foreign tax credits. The Company assesses the realizability of its deferred tax assets each reporting period through an analysis of potential sources of taxable income, including prior year taxable income available to absorb carryback of tax losses, reversals of existing taxable temporary differences, tax planning strategies, and forecasts of taxable income. The Company considers all negative and positive evidence, including the weight of the evidence, to determine if a valuation allowance against deferred tax assets is required. A valuation allowance is recorded against deferred tax assets to reflect the amount of deferred tax assets that is determined to be more-likely-than-not to be realized. As of December 31, 2024, and December 31, 2023, the Company’s valuation allowance against deferred tax assets was $ 45.3 million and $ 34.8 million, respectively. The Company has recorded a valuation allowance against certain tax attributes that the Company has determined are not more-likely-than-not to be realized, including certain foreign net operating loss carryforwards, foreign tax credit carryforwards, and capital loss carryforwards. From December 31, 2023 to December 31, 2024, the Company’s valuation allowance increased by $ 10.5 million. This increase relates to deferred tax assets recorded for net operating loss carryforwards and foreign tax credit carryforwards. The valuation allowance is recorded because the Company does not expect to have sufficient taxable income and foreign source income to utilize the net operating loss carryforwards and the foreign tax credit carryforwards before they expire. As of December 31, 2024, the Company has Net Operating Losses ("NOLs") of $ 1.7 million, $ 20.3 million, and $ 74.2 million for U.S. Federal, U.S. states and foreign jurisdictions, respectively. The utilization of the U.S. federal and U.S. state NOLs are subject to certain annual limitations. Of these NOL amounts, $ 1.7 million, $ 8.0 million and $ 12.9 million in U.S. Federal, U.S. states and foreign jurisdictions, respectively, do not expire. The remaining amounts of NOLs in U.S. states and in foreign jurisdictions will expire if not used between 2025 and 2045 . As of December 31, 2024, the Company has foreign tax credit carryforwards of $ 33.5 million. The Company has provided a valuation allowance of $ 33.5 million as the Company considers it is not more likely than not that these credits will be realized. These foreign tax credits start expiring in the year 2029 . A reconciliation of the beginning and ending balances of unrecognized tax benefits is as follows (in thousands): 2024 2023 2022 Beginning of year $ 25,497 $ 22,798 $ 21,181 Increases—current year tax positions 1,058 3,220 4,666 Increases—prior year tax positions 7,488 2,458 2,254 Decreases—prior year tax positions ( 1,826 ) ( 1,589 ) ( 3,537 ) Settlements ( 1,334 ) ( 1,026 ) ( 1,447 ) Lapse of statute of limitations ( 1,345 ) ( 364 ) ( 319 ) End of year $ 29,538 $ 25,497 $ 22,798 At December 31, 2024, and December 31, 2023, there are $ 28.6 million and $ 25.1 million of unrecognized tax benefits that if recognized would affect the Company’s effective tax rate. The Company recognizes interest and penalties related to unrecognized tax benefits as part of its income tax expense. During the years ended December 31, 2024, December 31, 2023, and December 31, 2022, the Company recognized approximately $ 1 million, $ 0.5 million, and $ 0.7 million in interest and penalties, respectively, in the consolidated statements of income. The total amount of interest and penalties accrued in the consolidated balance sheets was $ 5.6 million, $ 4.6 million, and $ 4.1 million as of December 31, 2024, December 31, 2023, and December 31, 2022, respectively. The Company conducts business globally and, as a result, the Company or one or more of its subsidiaries files income tax returns in the U.S. federal jurisdiction, various U.S. states, and foreign jurisdictions. The Company is subject to examination by tax authorities in several jurisdictions, including jurisdictions where the Company has significant activities, such as Canada, Qatar, Saudi Arabia and the United States. As of December 31, 2024, the Company’s U.S. federal income tax returns for tax years 2021 and forward remain subject to examination. U.S. states and foreign income tax returns remain subject to examination based on varying local statutes of limitations. The Company estimates that, within 12 months, it may decrease its uncertain tax positions by approximately $ 7.2 million as a result of concluding various tax audits and closing tax years. Although the Company believes its reserves for its tax positions are reasonable, the final outcome of tax audits could be significantly different, both favorably and unfavorably. It is reasonably possible that these audits may conclude in the next 12 months and that the unrecognized tax benefits the Company has recorded in relation to these tax years may change compared to the liabilities recorded for these periods. However, it is not currently possible to estimate the amount, if any, of such change.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2024
Commitments and Contingencies Disclosure [Abstract]
Contingencies	14. Contingencies The Company is subject to certain lawsuits, claims and assessments that arise in the ordinary course of business. Additionally, the Company has been named as a defendant in lawsuits alleging personal injuries as a result of contact with asbestos products at various project sites. Management believes that any significant costs relating to these claims will be reimbursed by applicable insurance and, although there can be no assurance that these matters will be resolved favorably, management believes that the ultimate resolution of any of these claims will not have a material adverse effect on our consolidated financial position, results of operations, or cash flows. A liability is recorded when it is both probable that a loss has been incurred and the amount of loss or range of loss can be reasonably estimated. When using a range of loss estimate, the Company records the liability using the low end of the range unless some amount within the range of loss appears at that time to be a better estimate than any other amount in the range. The Company records a corresponding receivable for costs covered under its insurance policies. Management judgment is required to determine the outcome and the estimated amount of a loss related to such matters. Management believes that there are no claims or assessments outstanding which would materially affect the consolidated results of operations or the Company’s financial position. In September 2015, a former Parsons employee filed an action in the United States District Court for the Northern District of Alabama against us as a qui tam relator on behalf of the United States (the “Relator”) alleging violation of the False Claims Act. The plaintiff alleges that, as a result of these actions, the United States paid in excess of $ 1 million per month between February and September 2006 that it should have paid to another contractor, plus $ 2.9 million to acquire vehicles for the contractor defendant to perform its security services. The lawsuit sought (i) that we cease and desist from violating the False Claims Act, (ii) monetary damages equal to three times the amount of damages that the United States has sustained because of our alleged violations, plus a civil penalty of not less than $ 5,500 and not more than $ 11,000 for each alleged violation of the False Claims Act, (iii) monetary damages equal to the maximum amount allowed pursuant to §3730(d) of the False Claims Act, and (iv) Relator’s costs for this action, including recovery of attorneys’ fees and costs incurred in the lawsuit. The United States government did not intervene in this matter as it is allowed to do so under the statute. The court heard dispositive motions in 2023, including Parsons’ motion for summary judgment. We are awaiting the court’s rulings upon such motions, which will determine whether a trial will be necessary for this matter in 2025. On July 1, 2024, a final judgment was filed with the clerk of the Superior Court of the State of California In and For the County of San Mateo with an award of damages in the total amount of approximately $ 102.5 million in favor of Parsons Transportation Group, Inc. and against Alstom Signaling Operations LLC (Alstom"). This proposed award relates back to a lawsuit Parsons initially filed against the Peninsula Corridor Joint Powers Board for breach of contract and wrongful termination in February 2017 (which was settled between Parsons and the Joint Powers Board in 2021) and a cross-complaint filed against Alstom Signaling Operations LLC in November 2017, as subsequently amended, for breach of contract, negligence and intentional misrepresentation. On September 23, 2024, the Court awarded pre-judgment interest in the amount of $ 34.0 million and amended the judgment accordingly to include such interest. Alstom filed a Notice of Appeal and has posted a bond as required under California law. At this time, the Company is unable to determine the probability of the outcome of the litigation. Federal government contracts are subject to audits, which are performed for the most part by the Defense Contract Audit Agency (“DCAA”). Audits by the DCAA and other agencies consist of reviews of our overhead rates, operating systems and cost proposals to ensure that we account for such costs in accordance with the Federal Acquisition Regulations (“FAR”). If the DCAA determines we have not accounted for such costs in accordance with the FAR, the DCAA may disallow these costs. The disallowance of such costs may result in a reduction of revenue and additional liability for the Company. Historically, the Company has not experienced any material disallowed costs as a result of government audits. However, the Company can provide no assurance that the DCAA or other government audits will not result in material disallowances for incurred costs in the future. All audits of costs incurred on work performed through 2014 have been closed, and years thereafter remain open. All of Parsons operating systems have been deemed adequate by the U.S. federal government. Although there can be no assurance that these matters will be resolved favorably, management believes that their ultimate resolution will not have a material adverse impact on the Company’s consolidated financial position, results of operations, or cash flows.

Retirement and Other Benefit Pl

Retirement and Other Benefit Plans	12 Months Ended
	Dec. 31, 2024
Retirement Benefits [Abstract]
Retirement and Other Benefit Plans	15. Retirement and Other Benefit Plans The Company’s principal retirement benefit plan is the ESOP, a stock bonus plan, established in 1975 to cover eligible employees of the Company and certain affiliated companies. Contributions of treasury stock to ESOP are made annually in amounts determined by the Company’s board of directors and are held in trust for the sole benefit of the participants. Shares allocated to a participant’s account are fully vested after three years of credited service, or in the event(s) of reaching age 65, death or disability while an active employee of the Company. As of December 31, 2024, the total shares of the Company’s common stock outstanding were 106,775,350 , of which 54,117,903 were held by the ESOP. As of December 31, 2023 , the total shares of the Company’s common stock outstanding were 105,839,978 , of which 59,879,857 were held by the ESOP. A participant’s interest in their ESOP account is redeemable upon certain events, including retirement, death, termination due to permanent disability, a severe financial hardship following termination of employment, certain conflicts of interest following termination of employment, or the exercise of diversification rights. Distributions from the ESOP of participants’ interests are made in the Company’s common stock based on quoted prices of a share of the Company’s common stock on the NYSE. A participant will be able to sell such shares of common stock in the market, subject to any requirements of the federal securities laws. Total ESOP contribution expense was approximately $ 59.8 million, $ 58.2 million and $ 54.7 million for the years ended December 31, 2024, December 31, 2023 and December 31, 2022, respectively, and is recorded in “Direct costs of contracts” and “Selling, general and administrative expense” in the consolidated statements of income. The Company also maintains a defined contribution plan (the “401(k) Plan”). Substantially all domestic employees are entitled to participate in the 401(k) Plan, subject to certain minimum requirements. The Company’s contributions to the 401(k) Plan for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 amounted to $ 37.7 million, $ 35.4 million, and $ 30.2 million, respectively. As part of an acquisition in 2014, the Company acquired a defined contribution pension plan, a defined benefit pension plan, and supplemental retirement plan. For the defined contribution pension plan, the Company contributes a base amount plus an additional amount based upon a predetermined formula. At December 31, 2024 and December 31, 2023, the defined benefit pension plan was in a net asset position of $ 1.3 million and $ 1.4 million, respectively, which is recorded in “Other noncurrent assets” on the consolidated balance sheets.

Investments in and Advances to

Investments in and Advances to Joint Ventures	12 Months Ended
	Dec. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Investments in and Advances to Joint Ventures	16. Investments in and Advances to Joint Ventures The Company participates in joint ventures to bid, negotiate and complete specific projects. The Company is required to consolidate these joint ventures if it holds the majority voting interest or if the Company meets the criteria under the consolidation model, as described below. The Company performs an analysis to determine whether its variable interests give the Company a controlling financial interest in a VIE for which the Company is the primary beneficiary and should, therefore, be consolidated. Such analysis requires the Company to assess whether it has the power to direct the activities of the VIE and the obligation to absorb losses or the right to receive benefits that could potentially be significant to the VIE. The Company analyzed all of its joint ventures and classified them into two groups: (1) joint ventures that must be consolidated because they are either not VIEs and the Company holds the majority voting interest, or because they are VIEs and the Company is the primary beneficiary; and (2) joint ventures that do not need to be consolidated because they are either not VIEs and the Company holds a minority voting interest, or because they are VIEs and the Company is not the primary beneficiary. Many of the Company’s joint venture agreements provide for capital calls to fund operations, as necessary; however, such funding is infrequent and is not anticipated to be material. Letters of credit outstanding described in ‘Note 11— Debt and Credit Facilities ” that relate to project ventures are approximately $ 176.7 million and $ 147.7 million at December 31, 2024 and December 31, 2023, respectively. In the table below, aggregated financial information relating to the Company’s joint ventures is provided because their nature, risk and reward characteristics are similar. None of the Company’s current joint ventures that meet the characteristics of a VIE are individually significant to the consolidated financial statements. Consolidated Joint Ventures The following represents financial information for consolidated joint ventures included in the consolidated financial statements as of and for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 (in thousands): 2024 2023 Current assets $ 519,450 $ 426,633 Noncurrent assets 9,841 14,295 Total assets 529,291 440,928 Current liabilities 296,774 260,286 Noncurrent liabilities 2,203 5,132 Total liabilities 298,977 265,418 Total joint venture equity $ 230,314 $ 175,510 2024 2023 2022 Revenue $ 788,702 $ 708,391 $ 483,888 Costs 676,258 613,186 422,559 Net income $ 112,444 $ 95,205 $ 61,329 Net income attributable to noncontrolling interests $ 55,612 $ 46,766 $ 29,901 The assets of the consolidated joint ventures are restricted for use only by the particular joint venture and are not available for the Company’s general operations. Unconsolidated Joint Ventures The Company accounts for its unconsolidated joint ventures using the equity method of accounting. Under this method, the Company recognizes its proportionate share of the net earnings of these joint ventures as “Equity in earnings (loss) of unconsolidated joint ventures” in the consolidated statements of income. The Company’s maximum exposure to loss as a result of its investments in unconsolidated VIEs is typically limited to the aggregate of the carrying value of the investment and future funding commitments. The following represents the financial information of the Company’s unconsolidated joint ventures as presented in their unaudited financial statements as of and for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 (in thousands): 2024 2023 Current assets $ 1,477,950 $ 1,607,953 Noncurrent assets 431,476 483,693 Total assets 1,909,426 2,091,646 Current liabilities 947,072 1,057,113 Noncurrent liabilities 469,808 518,647 Total liabilities 1,416,880 1,575,760 Total joint venture equity $ 492,546 $ 515,886 Investments in and advances to unconsolidated joint $ 138,759 $ 128,204 2024 2023 2022 Revenue $ 2,118,799 $ 2,313,420 $ 2,406,407 Costs 2,108,768 2,310,114 2,325,472 Net income $ 10,031 $ 3,306 $ 80,935 Equity in (losses) earnings of unconsolidated joint ventures $ ( 23,361 ) $ ( 47,751 ) $ 16,347 The Company had net contributions to its unconsolidated joint ventures of $ 38.8 million and $ 65.2 million for the years ended December 31, 2024 and December 31, 2023 , respectively and received net distributions from its unconsolidated joint ventures of $ 20.2 million for the year ended December 31, 2022. The following table presents certain financial statement impacts from changes in estimates on unconsolidated joint ventures in the Critical Infrastructure segment. 2024 2023 2022 Operating loss $ ( 51,715 ) $ ( 83,398 ) $ ( 13,817 ) Net loss ( 44,682 ) ( 61,842 ) ( 10,335 ) Diluted loss per share $ ( 0.40 ) $ ( 0.54 ) $ ( 0.09 )

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2024
Related Party Transactions [Abstract]
Related Party Transactions	17. Related Party Transactions The Company often provides services to unconsolidated joint ventures and revenues include amounts related to recovering overhead costs for these services. For the years ended December 31, 2024, December 31, 2023 and December 31, 2022, revenues included $ 182.6 million , $ 213.8 million, and $ 217.4 million, respectively, related to services the Company provided to unconsolidated joint ventures. For the years ended December 31, 2024, December 31, 2023 and December 31, 2022, the Company incurred approximately $ 143.2 million , $ 153.7 million and $ 157.6 million, respectively, of reimbursable costs. Amounts included in the consolidated balance sheets related to services the Company provided to unconsolidated joint ventures are as follows (in thousands): 2024 2023 Accounts receivable $ 38,443 $ 38,898 Contract assets 11,540 38,009 Contract liabilities 10,776 15,287 Amounts presented above for comparable periods have been updated to reflect all unconsolidated joint ventures.

Fair Value

Fair Value	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Fair Value	18. Fair Value The authoritative guidance on fair value measurement defines fair value as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date (referred to as an “exit price”). At December 31, 2024 and December 31, 2023 the Company’s financial instruments include cash, cash equivalents, accounts receivable, accounts payable, and other liabilities. The fair values of these financial instruments approximate their carrying values due to their short-term maturities. Investments measured at fair value are based on one or more of the following three valuation techniques: • Market approach —Prices and other relevant information generated by market transactions involving identical or comparable assets or liabilities; • Cost approach —Amount that would be required to replace the service capacity of an asset (i.e., replacement cost); and • Income approach —Techniques to convert future amounts to a single present amount based on market expectations (including present value techniques, option-pricing models and lattice models). In addition, the guidance establishes a fair value hierarchy that prioritizes the inputs to valuation techniques used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets and liabilities (Level 1 measurements) and the lowest priority to unobservable inputs (Level 3 measurements). The three levels of the fair value hierarchy are: Level 1 Unadjusted quoted prices in active markets that are accessible at the measurement date for identical assets and liabilities; Level 2 Pricing inputs that include quoted prices for similar assets and liabilities in active markets and inputs that are observable for the asset or liability, either directly or indirectly, for substantially the full term of the derivative instrument; and Level 3 Prices or valuations that require inputs that are both significant to the fair value measurements and unobservable. The methods described above may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. Furthermore, while the Company believes its valuation methods are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different fair value measurement at the reporting date. Financial assets and liabilities measured at fair value on a recurring basis are as follows: Fair value as of December 31, 2024 (in thousands): Level 1 Level 2 Level 3 Total Assets related to defined contribution plan Mutual funds $ 875 $ — $ — $ 875 Fixed income — 6,627 — 6,627 Cash and cash equivalents 349 — — 349 Total assets at fair value $ 1,224 $ 6,627 $ — $ 7,851 Fair value as of December 31, 2023 (in thousands): Level 1 Level 2 Level 3 Total Assets related to defined contribution plan Mutual funds $ 1,840 $ — $ — 1,840 Fixed income — 6,568 — 6,568 Cash and cash equivalents 355 — — 355 Total assets at fair value $ 2,195 $ 6,568 — $ 8,763 Contingent consideration Earnout liability $ - $ - $ 2,300 $ 2,300 Total liabilities at fair value $ - $ - $ 2,300 $ 2,300 As described in “Note 15— Retirement and Other Benefits Plans ”, the Company acquired a defined contribution pension plan, a defined benefit pension plan, and supplemental retirement plans. At December 31, 2024 and December 31, 2023, the Company measured the mutual funds held within the defined benefit pension plan at fair value using unadjusted quoted prices in active markets that are accessible for identical assets. The Company measured the fixed income securities using market bid and ask prices. The inputs that are significant to the valuation of fixed income securities are generally observable, and therefore have been classified as Level 2. In determining the fair value of acquired intangible assets from our business acquisitions, the Company uses the multi-period excess earnings method to value customer relationships and backlog and values developed technologies using the relief-from royalty method. These valuation methods use significant unobservable inputs classified within Level 3 of the fair value hierarchy. See "Note 2— Summary of Significant Accounting Policies." We measure contingent consideration at fair value on a recurring basis using significant unobservable inputs classified within Level 3 of the fair value hierarchy. See "Note 2— Summary of Significant Accounting Policies" and "Note 3— Acquisitions" for further information. With respect to equity-based compensation, for restricted stock units containing service conditions or service and performance conditions, the grant date fair value is based on the closing stock price of a share of the Company’s common stock on the NYSE on the grant date. For awards that include market conditions, the grant date fair value is determined using a Monte Carlo simulation. The carrying values and estimated fair values of our financial instruments that are not required to be recorded at fair value in our consolidated balance sheets, on the basis of Level 1 inputs for the Company's convertible notes and Level 2 inputs for the delayed draw term loan, were as follows (in thousands): December 31, 2024 December 31, 2023 Carrying Value Fair Value Carrying Value Fair Value Liabilities: Convertible senior notes due 2025 $ 113,405 $ 233,206 $ 400,000 $ 568,000 Convertible senior notes due 2029 800,000 939,280 - - Delayed draw term loan 350,000 350,000 350,000 350,000 Total $ 1,263,405 $ 1,522,486 $ 750,000 $ 918,000

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Earnings Per Share	19. Earnings Per Share Basic earnings per share (“EPS”) is computed using the weighted average number of shares outstanding during the period and income available to shareholders. Diluted EPS includes additional common shares that would have been outstanding if potential common shares with a dilutive effect had been issued using the if-converted method for Convertible Debt and the treasury stock method for all other instruments. Under the treasury stock method, the weighted average number of shares outstanding is adjusted to reflect the dilutive effects of stock-based awards and shares underlying the warrants related to the convertible senior notes due 2025. Under the if-converted method: 1. Convertible Senior Notes due 2025: a. Income available to shareholders is adjusted to add back interest expense, after tax (unless antidilutive). b. Weighted average number of shares outstanding is adjusted to include the shares underlying the convertible debt (unless antidilutive). c. Shares underlying the bond hedge (unless antidilutive). 2. Convertible Senior Notes due 2029: a. Interest has been excluded from the numerator and no shares have been included in the denominator of diluted EPS, as the principal amount of convertible debt will be settled in cash with any excess conversion value settled in cash or shares of common stock. b. Excludes shares underlying the capped call as the shares are antidilutive. The following table reconciles the numerator and denominator used to compute basic and diluted EPS for the years ended December 31, 2024, December 31, 2023, and December 31, 2022 (in thousands): 2024 2023 2022 Numerator for Basic and Diluted EPS: Net income attributable to Parsons Corporation - basic $ 235,053 $ 161,149 $ 96,664 Convertible senior notes if-converted method interest adjustment 2,932 2,291 2,176 Net income attributable to Parsons Corporation - diluted $ 237,985 $ 163,440 $ 98,840 Denominator for Basic and Diluted EPS: Basic weighted average number of shares outstanding 106,274 104,992 103,758 Dilutive effect of stock-based awards 1,778 1,173 808 Dilutive effect of warrants 494 — — Dilutive effect of convertible senior notes 3,628 8,917 8,917 Diluted weighted average number of shares outstanding 112,174 115,082 113,483 Earnings per share: Basic $ 2.21 $ 1.53 $ 0.93 Diluted $ 2.12 $ 1.42 $ 0.87 Anti-dilutive stock-based awards excluded from the calculation of earnings per share for the years ended December 31, 2024, December 31, 2023, and December 31, 2022 were 4,562 , 5,423 , and 15,113 , respectively. Share Repurchases On August 9, 2021, the Company’s Board of Directors authorized the Company to acquire a number of shares of Common Stock having an aggregate market value of not greater than $ 100 million from time to time, commencing on August 12, 2021 . The Board further amended this authorization in August 2022 to remove the prior expiration date and grant executive leadership the discretion to determine the price for such share repurchases. The Board further amended this authorization in February 2024 to restore the repurchase capacity to $ 100 million and removed the $ 25 million quarterly cap on such repurchases. At the time of the February 2024 authorization, the Company had repurchased shares with an aggregated market value (including fees) of $ 54.7 million. The aggregate market value of shares of Common Stock the Company is authorized to acquire, from both the August 2021 and February 2024 authorizations, is not greater than $ 154.7 million. As of December 31, 2024 , the Company has $ 75 million remaining under the stock repurchase program. Repurchased shares of common stock are retired and included in “Repurchases of common stock” in cash flows from financing activities in the Consolidated Statements of Cash Flows. The primary purpose of the Company’s share repurchase program is to reduce the dilutive effect of shares issued under the Company’s ESOP and other stock benefit plans. The timing, amount and manner of share repurchases may depend upon market conditions and economic circumstances, availability of investment opportunities, the availability and costs of financing, the market price of the Company's common stock, other uses of capital and other factors. The following table summarizes the repurchase activity under the stock repurchase program. 2024 2023 Total shares repurchased 287,005 233,010 Total shares retired 287,005 233,010 Average price paid per share $ 87.10 $ 47.21

Segments Information

Segments Information	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Segments Information	20. Segments Information The Company operates in two reportable segments: Federal Solutions and Critical Infrastructure. The Federal Solutions segment provides advanced technical solutions to the U.S. government, delivering timely, cost-effective hardware, software and services for mission-critical projects. The segment provides advanced technologies, supporting national security missions in cyber operations, missile defense, and military facility modernization, logistics support, hazardous material remediation and engineering services. The Critical Infrastructure segment provides integrated engineering and management services for complex physical and digital infrastructure around the globe. The Critical Infrastructure segment is a technology innovator focused on next generation digital systems and complex structures. Industry leading capabilities in engineering and project management allow the Company to deliver significant value to customers by employing cutting-edge technologies, improving timelines and reducing costs. The Company defines its reportable segments based on the way the chief operating decision maker (“CODM”), its Chief Executive Officer, evaluates the performance of each segment and manages the operations of the Company for purposes of allocating resources among the segments. The CODM evaluates segment operating performance using segment Revenue, segment direct cost of contracts, segment Selling, General and Administrative expense and segment Adjusted EBITDA attributable to Parsons Corporation. The Company defines Adjusted EBITDA attributable to Parsons Corporation as Adjusted EBITDA excluding Adjusted EBITDA attributable to noncontrolling interests. The Company defines Adjusted EBITDA as net income (loss) attributable to Parsons Corporation, adjusted to include net income (loss) attributable to noncontrolling interests and to exclude interest expense (net of interest income), provision for income taxes, depreciation and amortization and certain other items that are not considered in the evaluation of ongoing operating performance. These other items include net income (loss) attributable to noncontrolling interests, asset impairment charges, income and expense recognized on litigation matters, expenses incurred in connection with acquisitions and other non-recurring transaction costs and expenses related to our prior restructuring. Adjusted EBITDA is the measure of our operating performance used by the CODM to assess our segments’ financial performance. The CODM uses Adjusted EBITDA for business planning purposes, including to manage our segments against internal projected results of operations and measure the performance of our segments generally. The following tables present segment information provided to the CODM, as of each fiscal year presented, along with a reconciliation of segment adjusted EBITDA attributable to Parsons Corporation to net income attributable to Parsons Corporation for the periods presented (in thousands): Twelve Months Ended December 31, 2024 Federal Critical Total Revenue $ 4,007,114 $ 2,743,462 $ 6,750,576 Direct cost of contracts ( 3,187,829 ) ( 2,156,325 ) ( 5,344,154 ) Selling, general and administrative expenses (a) ( 157,442 ) ( 146,744 ) ( 304,186 ) Equity in earnings (losses) of unconsolidated joint ventures 3,254 ( 26,615 ) ( 23,361 ) Other segment items (b) ( 249,759 ) ( 280,877 ) ( 530,636 ) Adjusted EBITDA attributable to Parsons Corporation $ 415,338 $ 132,901 548,239 Reconciliation: Segment Adjusted EBITDA to Net Income Attributable to Parsons Corporation Adjusted EBITDA attributable to non-controlling interests 56,714 Depreciation and amortization ( 99,251 ) Interest expense, net ( 40,154 ) Income tax expense ( 76,986 ) Equity-based compensation expense ( 61,492 ) Convertible debt repurchase loss ( 18,355 ) Transaction related costs (c) ( 17,138 ) Other (e) ( 912 ) Net income including noncontrolling interests 290,665 Net income attributable to noncontrolling interests ( 55,612 ) Net income attributable to Parsons Corporation $ 235,053 Twelve Months Ended December 31, 2023 Federal Critical Total Revenue $ 3,020,701 $ 2,422,048 $ 5,442,749 Direct cost of contracts ( 2,375,350 ) ( 1,861,385 ) ( 4,236,735 ) Selling, general and administrative expenses (a) ( 129,507 ) ( 129,747 ) ( 259,254 ) Equity in earnings (losses) of unconsolidated joint ventures 4,190 ( 51,941 ) ( 47,751 ) Other segment items (b) ( 230,784 ) ( 251,190 ) ( 481,974 ) Adjusted EBITDA attributable to Parsons Corporation 289,250 127,785 417,035 Reconciliation: Segment Adjusted EBITDA to Net Income Attributable to Parsons Corporation Adjusted EBITDA attributable to non-controlling interests 47,638 Depreciation and amortization ( 119,973 ) Interest expense, net ( 29,306 ) Income tax expense ( 56,138 ) Equity-based compensation expense ( 36,151 ) Transaction related costs (c) ( 12,013 ) Restructuring expense (d) ( 1,244 ) Other (e) ( 1,933 ) Net income including noncontrolling interests 207,915 Net income attributable to noncontrolling interests ( 46,766 ) Net income attributable to Parsons Corporation $ 161,149 Twelve Months Ended December 31, 2022 Federal Critical Total Revenue $ 2,212,987 $ 1,982,285 $ 4,195,272 Direct cost of contracts ( 1,703,297 ) ( 1,545,253 ) ( 3,248,550 ) Selling, general and administrative expenses (a) ( 117,759 ) ( 110,468 ) ( 228,227 ) Equity in earnings of unconsolidated joint ventures 3,677 12,670 16,347 Other segment items (b) ( 196,604 ) ( 215,849 ) ( 412,453 ) Adjusted EBITDA attributable to Parsons Corporation 199,004 123,385 322,389 Reconciliation: Segment Adjusted EBITDA to Net Income Attributable to Parsons Corporation Adjusted EBITDA attributable to non-controlling interests 30,393 Depreciation and amortization ( 120,501 ) Interest expense, net ( 22,219 ) Income tax expense ( 39,657 ) Equity-based compensation expense ( 24,354 ) Transaction related costs (c) ( 16,270 ) Restructuring expense (d) ( 213 ) Other (e) ( 3,003 ) Net income including noncontrolling interests 126,565 Net income attributable to noncontrolling interests ( 29,901 ) Net income attributable to Parsons Corporation $ 96,664 (a) The amount of selling, general and administrative expenses (“SG&A”) is total SG&A excluding allocations. (b) The amount of other segment items is the difference between segment revenue less direct cost of contracts, segment SG&A expenses, equity in earnings (losses) of unconsolidated joint ventures, and Adjusted EBITDA attributable to Parsons Corporation. Other segment items primarily include: i. Corporate and shared segment SG&A (excluding Adjusted EBITDA items) ii. Noncontrolling interests attributable to operating income and other income/expense iii. Bad debt expense iv. Sublease income v. Foreign currency gain/loss, and vi. Certain other income/expense items (c) Reflects costs incurred in connection with acquisitions, and other non-recurring transaction costs, primarily fees paid for professional services and employee retention. (d) Reflects costs associated with and related to our corporate restructuring initiatives. (e) Includes a combination of gain/loss related to sale of fixed assets, software implementation costs, and other individually insignificant items that are non-recurring in nature. Asset information by segment is not a key measure of performance used by the CODM. The following table presents revenues and property and equipment, net by geographic area (in thousands): 2024 2023 2022 Revenues: North America $ 5,677,933 $ 4,481,492 $ 3,463,128 Middle East 1,052,509 943,175 710,830 Rest of World 20,134 18,082 21,314 Total revenues $ 6,750,576 $ 5,442,749 $ 4,195,272 Property and equipment, net North America $ 101,044 $ 91,766 $ 91,217 Middle East 10,531 7,191 4,833 Total property and equipment, net $ 111,575 $ 98,957 $ 96,050 North America revenue includes $ 5.2 billion, $ 4.1 billion and $ 3.2 billion of United States revenue for the years ended December 31, 2024, December 31, 2023 and December 31, 2022, respectively. North America property and equipment, net includes $ 94.0 million , $ 83.9 million and $ 84.4 million of property and equipment, net in the United States at December 31, 2024, December 31, 2023 and December 31, 2022, respectively. The geographic location of revenue is determined by the location of the customer. The following table presents revenues by business lines (in thousands): 2024 2023 2022 Revenue: Defense & Intelligence $ 1,772,481 $ 1,539,968 $ 1,368,779 Engineered Systems 2,234,633 1,480,733 844,208 Federal Solutions revenues 4,007,114 3,020,701 2,212,987 Infrastructure – North America 1,683,664 1,472,768 1,265,376 Infrastructure – Europe, Middle East and Africa 1,059,798 949,280 716,909 Critical Infrastructure revenues 2,743,462 2,422,048 1,982,285 Total revenues $ 6,750,576 $ 5,442,749 $ 4,195,272 Effective June 1, 2022, the Company made changes to its Federal Solutions business units by transferring a portion of legacy Defense and Intelligence business unit to the Engineered Systems business unit. Effective October 1, 2023, the Company reorganized its Critical Infrastructure business units from Mobility Solutions and Connected Communities to Infrastructure – North America and Infrastructure – Europe, Middle East and Africa. The prior year information in the table above has been reclassified to conform to the business unit changes.

Quarterly Information - Unaudit

Quarterly Information - Unaudited	12 Months Ended
	Dec. 31, 2024
Quarterly Financial Information Disclosure [Abstract]
Quarterly Information - Unaudited	21. Quarterly Information - Unaudited The following table presents selected quarterly financial information (in thousands except per share data). Quarter Ended March 31, 2024 December 31, 2024 Federal Solutions revenue $ 909,608 $ 1,003,323 Critical Infrastructure revenue 626,068 730,994 Total revenue 1,535,676 1,734,317 Operating income 101,844 99,812 Convertible debt repurchase loss (1) ( 18,355 ) - Income tax expense (1) ( 13,324 ) ( 18,729 ) Net income attributable to Parsons Corporation (1) 39,750 54,180 Earnings per share: Basic $ 0.37 $ 0.51 Diluted (2) $ 0.37 $ 0.49 1 Presents the revised quarterly financial data resulting from the adoption of Accounting Standards Update (“ASU”) 2024-04 as of January 1, 2024 on a prospective basis. As a result of the adoption of ASU 2024-04 , the Company reversed a loss on extinguishment of debt for the partial repurchase of the Convertible Senior Notes due 2025 and recorded the repurchase transaction as an induced conversion. This change from extinguishment to inducement accounting resulted in the Company (i.) reversing the $ 211.0 million loss and the related $ 49.9 million tax benefit on extinguishment of debt, recorded in Q1 2024, (ii.) recording a $ 18.4 million convertible debt repurchase loss, (iii.) the difference between the extinguishment loss and inducement expense of $ 192.6 million recorded to equity, and (iv.) the related tax benefit of $ 45.6 million recorded to equity. See "Note 2—Summary of Significant Accounting Polices—New Accounting Pronouncements " for a further discussion of the first quarter 2024 extinguishment accounting and subsequent change to inducement accounting. 2 Diluted earnings per share prior to the adoption of ASU 2024-04 did not include certain adjustments as their inclusion would have been antidilutive. Subsequent to the adoption of ASU 2024-04 these adjustments are no longer antidilutive. Dilutive adjustments include if converted interest of $ 2.8 million, 1.5 million shares related to stock based awards and 6.8 million shares related to convertible senior notes. Inclusion of these dilution adjustments resulted in dilutive net income attributable to Parsons Corporation of $ 42.5 million and total diluted shares of 114.4 million for the quarter ended March 31, 2024.

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2024
Subsequent Events [Abstract]
Subsequent Events	22. Subsequent Events After the year ended December 31, 2024, the Company entered into a merger agreement to acquire a 100 % ownership interest in TRS Group, Inc. ("TRS") for approximately $ 36 million from cash on hand. Headquartered in Indianapolis, Indiana, TRS is an environmental solutions firm that specializes in remediation technology. At the time of the filing of this Form 10-K, the Company has just started the process of obtaining the relevant data to make the required acquisition related disclosures. This acquisition is not material to the Company's consolidated financial statements.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2024
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	PARSONS CORPORATION AND SUBSIDIARIES Schedule II—Valuation and Qualifying Accounts (in thousands) Balance at Additions Deductions Other and foreign Balance at 2024 Allowance for doubtful accounts $ 3,952 $ - $ ( 66 ) $ - $ 3,886 Valuation allowance on deferred tax assets 34,779 11,452 ( 328 ) ( 585 ) 45,318 2023 Allowance for doubtful accounts 4,011 $ - $ ( 59 ) $ - 3,952 Valuation allowance on deferred tax assets 28,705 8,209 ( 2,437 ) 302 34,779 2022 Allowance for doubtful accounts 3,955 59 ( 3 ) - 4,011 Valuation allowance on deferred tax assets $ 27,348 3,656 ( 2,180 ) ( 119 ) $ 28,705

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) and include the accounts of Parsons Corporation and its subsidiaries and affiliates which it controls. Interests in joint ventures that are controlled by the Company, or for which the Company is otherwise deemed to be the primary beneficiary, are consolidated. For joint ventures in which the Company does not have a controlling interest, but exerts significant influence, the Company applies the equity method of accounting. Intercompany accounts and transactions are eliminated in consolidation. Certain amounts may not foot due to rounding.
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in accordance with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual amounts could differ from those estimates. The Company’s most significant estimates and judgments involve revenue recognition with respect to the determination of the costs to complete contracts and transaction price; determination of self-insurance reserves; useful lives of property and equipment and intangible assets; valuation of deferred income tax assets and uncertain tax positions, among others.
ESOP	ESOP The Company maintains a non-leveraged ESOP for eligible employees, for which the Company contributes shares of its own stock to the ESOP trust each year. Throughout the year, as employee services are rendered, the Company records compensation expense based on salaries of eligible employees. At each reporting period, the shares held within the ESOP or committed to be contributed to the ESOP are adjusted to their redemption value through an offsetting charge or credit to retained earnings.
Treasury Stock	Treasury Stock The Company records treasury stock purchases under the cost method whereby the entire cost of the acquired stock is recorded as treasury stock. The Company records the reissuance of treasury stock using the first-in, first-out method of accounting. Contributions of 633,033 shares, 915,113 shares, and 1,188,129 shares of common stock were made to the ESOP in 2024, 2023 and 2022, respectively.
Shares Repurchases	Share Repurchases During the third quarter of 2021, the Company’s Board of Directors authorized the Company to acquire a number of shares of Common Stock having an aggregate market value of not greater than $ 100,000,000 from time to time. The Board further amended this authorization in February 2024 to restore the repurchase capacity to $ 100 million and removed the $ 25 million quarterly cap on such repurchases. At the time of the February 2024 authorization, the Company had repurchased shares with an aggregated market value (including fees) of $ 54.7 million. The aggregate market value of shares of Common Stock the Company is authorized to acquire is now not greater than $ 154.7 million. Repurchased shares of common stock are retired and included in “Repurchases of common stock” in cash flows from financing activities in the Consolidated Statements of Cash Flows.
Earnings per Share	Earnings per Share Basic earnings per common share (“EPS”) is calculated by dividing Net income by the weighted average number of common shares outstanding during the year. Diluted earnings per common share is calculated using the if-converted method by dividing adjusted net income by adjusted weighted average outstanding shares, assuming conversion of all potentially dilutive securities. Upon contribution to the ESOP, the shares become outstanding and are included within the earnings per share computations.
Revenue Recognition	Revenue Recognition In accordance with Account Standard Update ("ASC") 606 - Revenue From Contracts With Customers , the Company follows the five-step process in ASC 606 to recognize revenue: 1. Identify the contract 2. Identify performance obligations 3. Determine the transaction price 4. Allocate the transaction price 5. Recognize revenue Contracts —Revenue is derived from long-term contracts with customers whereby the Company provides planning, design, engineering, technical, and construction and program management services. The Company has contracts with the United States federal government that contain provisions requiring compliance with the United States Federal Acquisition Regulation (“FAR”) and the United States Cost Accounting Standards (“CAS”). These regulations are generally applicable to all of the Company’s federal government contracts and are partially or fully incorporated in some local and state agency contracts. Most of the Company’s federal government contracts are subject to termination at the convenience of the client. These contracts typically provide for reimbursement of costs incurred and payment of fees earned through the date of such termination. The Company enters into the following types of contracts with its customers: Cost-Plus—Under cost-plus contracts, the Company is reimbursed for allowable or otherwise defined costs incurred, plus a fee. The contracts may also include incentives for various performance criteria, including quality, timeliness, safety and cost-effectiveness. In addition, costs are generally subject to review by clients and regulatory audit agencies, and such reviews could result in costs being disputed as non-reimbursable under the terms of the contract. Time-and-Materials—Under time-and-materials contracts, hourly billing rates are negotiated and charged to clients based on the actual time spent on a project. In certain cases, these contracts may be subject to maximum contract values. In addition, clients reimburse actual out-of-pocket costs for materials and other direct incidental expenditures that are incurred in connection with the performance under the contract. Fixed-Price—The Company enters into two types of fixed-price contracts: firm fixed-price (“FFP”) and fixed-price per unit (“FPPU”). Under FFP contracts, clients pay an agreed fixed-amount negotiated in advance for a specified scope of work. Contract Costs —Contract costs consist of direct costs on contracts, including labor and materials, amounts payable to subcontractors, direct overhead costs and equipment expense (primarily depreciation, fuel, maintenance and repairs). All contract costs are recorded as incurred. Changes to estimated contract costs, either due to unexpected events or revisions to management’s initial estimates, for a given project are recognized in the period in which they are determined. Pre-contract costs are expensed as incurred unless they are expected to be recovered from the client, generate or enhance resources that will be used in satisfying performance obligations in the future and directly relate to an existing or anticipated contract. Costs to mobilize equipment and labor to a job site, prior to substantive work beginning (“mobilization costs”) are capitalized as incurred and amortized over the expected duration of the contract. Additionally, the Company may incur incremental costs to obtain certain contracts, such as selling and market costs, bid and proposal costs, sales commissions, and legal fees, certain of which can be capitalized if they are recoverable under the contract. Capitalized contract costs are included in other current assets on the consolidated balance sheets and were not material as of December 31, 2024 and December 31, 2023. Performance Obligations —A performance obligation is a promise in a contract to transfer a distinct good or service to the customer and is the unit of account in ASC 606. The transaction price of a contract is allocated to each distinct performance obligation and recognized as revenue when, or as, the performance obligation is satisfied. To the extent a contract is deemed to have multiple performance obligations, the Company allocates the transaction price of the contract to each performance obligation using our best estimate of the standalone selling price of each distinct good or service in the contract. The Company determines the relative standalone selling price utilizing observable prices for the sale of the underlying goods or services. Contracts are considered to have a single performance obligation if the promise to transfer the individual goods or services is not separately identifiable from other promises in the contracts or is not distinct in the context of the contract, which is mainly because the Company provides a significant service of integrating a complex set of tasks and components into a single project or capability. Engineering and construction contracts are generally accounted for as a single performance obligation while our engineering and construction supervision contracts are accounted for as two separate performance obligations. When providing construction supervision services, the Company is not liable for the construction of the asset, but has an overall responsibility to oversee, coordinate, measure, and evaluate the quality of construction work and the performance of the construction contractor on behalf of the customer. Customers are generally billed as the Company satisfies its performance obligations and payment terms typically range from 30 to 120 days from the invoice date. Billings under certain fixed-price contracts may be based upon the achievement of specified milestones, while some arrangements may require advance customer payment. The Company’s contracts generally do not include a significant financing component. Variable Consideration —The transaction price for the Company’s contracts may include variable consideration, which includes increases to transaction price for approved and unpriced change orders, claims and incentives, and reductions to transaction price for liquidated damages. Change orders, claims and incentives are generally not distinct from the existing contract due to the significant integration service provided in the context of the contract and are accounted for as a modification of the existing contract and performance obligation. The Company estimates variable consideration for a performance obligation utilizing one of the two prescribed methods, depending on which method better predicts the amount of consideration to which the Company will be entitled (or the amount the Company expects to incur in the case of liquidated damages). Such methods are: (a) the expected value method, whereby the amount of variable consideration to be recognized represents the sum of probability weighted amounts in a range of possible consideration amounts, and (b) the most likely amount method, whereby the amount of variable consideration to be recognized represents the single most likely amount in a range of possible consideration amounts. When applying these methods, the Company considers all information that is reasonably available, including historical, current and estimates of future performance. The expected value method is utilized in situations where a contract contains a large number of possible outcomes, while the most likely amount method is utilized in situations where a contract has only two possible outcomes. The Company includes variable consideration in the estimated transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur or when the uncertainty associated with the variable consideration is resolved. The Company’s estimates of variable consideration and determination of whether to include estimated amounts in transaction price are based largely on an assessment of anticipated performance and all information (historical, current and forecasted) that is reasonably available. The effect of variable consideration on the transaction price of a performance obligation is recognized as an adjustment to revenue on a cumulative catch-up basis. Change Orders —Change orders, which are a normal and recurring part of business, may include changes in specifications or design, manner of performance, facilities, equipment, materials, sites and period of completion of the work. The Company or customer may initiate change orders. Most change orders are not distinct from the existing contract and are accounted for as part of that existing contract. The effect of a change order on the transaction price and measure of progress for the performance obligation to which it relates is recognized as an adjustment to revenues (either as an increase in or a reduction of revenues) on a cumulative catch-up basis. Revenues from unpriced change orders are recognized to the extent of the amounts the Company expects to recover, consistent with the variable consideration policy discussed above. If it is probable that a reversal of revenues will occur, the costs attributable to change orders are treated as contract costs without incremental revenues. To the extent change orders included in the price are not resolved in the Company’s favor, there could be reductions in, or reversals of previously reported amounts of, revenues and profits, and charges against current earnings, which could be material. Claims Revenue —Claims revenue are amounts in excess of agreed contract prices that the Company seeks to collect from clients or others for customer-caused delays, errors in specifications and designs, contract terminations, change orders that are in dispute, or other causes of unanticipated additional contract costs, including factors outside of our control, and therefore the Company believes it is entitled to additional compensation. Claims revenue, when recorded, is only recorded to the extent it is probable that a significant reversal of cumulative revenue recognized will not occur. The Company includes certain claims in the transaction price when the claims are legally enforceable, the Company considers collection to be probable and believes it can reliably estimate the ultimate value. The Company continues to engage in negotiations with its customers on outstanding claims. However, these claims may be resolved at amounts that differ from current estimates, which could result in increases or decreases in future estimated contract profits or losses. Warranties —In most cases, contracts include assurance-type warranties that the Company’s performance is free from material defect and consistent with the specifications of the Company’s contracts, which do not give rise to a separate performance obligation. To the extent the warranty terms provide the customer with an additional service, such as extended maintenance services, such warranty is accounted for as a separate performance obligation. Revenue recognized over time —The Company’s performance obligations are generally satisfied over time as work progresses because of continuous transfer of control to the customer and the Company has the right to bill the customer as costs are incurred. Typically, revenue is recognized over time using an input measure (i.e. costs incurred to date relative to total estimated costs at completion) to measure progress. The Company generally uses the cost-to-cost measure of progress method because it best depicts the transfer of control to the customer which occurs as the Company incurs costs on its contracts. Under the cost-to-cost measure of progress method, the extent of progress towards completion is measured based on the ratio of total costs incurred to-date to the total estimated costs at completion of the performance obligation. Revenues, including estimated fees or profits, are recorded proportionally as costs are incurred. Any expected losses on construction-type contracts in progress are charged to earnings, in total, in the period the losses are identified. The Company recognizes adjustments in estimated profit on contracts under the cumulative catch-up method. Under this method, the impact of the adjustment on profit recorded to date is recognized in the period the adjustment is identified. Revenue and profit in future periods of contract performance is recognized using the adjusted estimate. If at any time the estimate of contract profitability indicates an anticipated loss on the contract, the Company recognizes the total loss in the period it is identified. Right to invoice practical expedient —For performance obligations satisfied over time where the Company has a right to consideration from a customer in an amount that corresponds directly with the value of the Company’s performance to-date, the Company recognizes revenue in the amount to which it has a right to invoice. For the Company’s reimbursable services contracts, revenue is recognized using the right to invoice practical expedient, or on a cost-to-cost measure of progress method. The Company will select the method that best represents progress on a project. Revenue recognized at a point in time —For performance obligations satisfied at a point in time, revenue is recognized when the services are performed, control is transferred, and the performance obligation is complete. The Company recognizes revenue at a point in time for vehicle inspection services. Revenue related to the inspection service is recognized for each vehicle inspection at the point the Company has completed the inspection. In the Company’s industry, recognition of profit on long-term contracts requires the use of assumptions and estimates related to total contract revenue and in particular estimated claims revenue, total estimated cost at completion, and the measurement of progress towards completion. Estimates are continually evaluated as work progresses and are revised when necessary. When a change in estimate is determined to have an impact on contract profit, the Company records a positive or negative adjustment to the consolidated statements of income.
Cash Equivalents	Cash Equivalents The Company considers all highly liquid investments with original maturities of less than three months to be cash equivalents. Cash equivalent investments are carried at cost, which approximates fair value, and consist primarily of United States Treasuries, time deposits, and other forms of short-term fixed income investments.
Restricted Cash and Investments	Restricted Cash and Investments Restricted cash and investments held in trust accounts represent collateral for certain incentive programs.
Accounts Receivable, Net	Accounts Receivable, Net Accounts receivable includes billed and unbilled amounts and are recognized in the period when the Company’s rights to receive consideration are unconditional. The Company establishes an allowance for doubtful accounts based on consideration of trends in actual and forecasted credit quality of clients, including delinquency and payment history, type of client, such as a government agency or commercial sector client, and general economic conditions and particular industry conditions that may affect a client’s ability to pay. Past due receivable balances are written off when internal collection efforts have been unsuccessful in collecting the amounts due.
Contract Assets and Contract Liabilities	Contract Assets and Contract Liabilities Projects with performance obligations recognized over time that have revenue recognized to-date in excess of cumulative billings and unbilled accounts receivable are reported on our consolidated balance sheets as “Contract assets”. Contract retentions, included in contract assets, represent amounts withheld by clients, in accordance with underlying contract terms, until certain conditions are met or the project is completed. The operating cycle for certain long-term contracts may extend beyond one year, and, accordingly, collection of retainage on those contracts may extend beyond one year. Contract assets are reclassified to accounts receivable when the right to consideration becomes unconditional. Contract liabilities on uncompleted contracts represent the excess of cash collected from clients and billings to clients on contracts in advance of work performed over the amount of revenue recognized and provisions for losses. The majority of these amounts are expected to be earned within 12 months and are classified as current liabilities.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which potentially subject the Company to concentrations of credit risk consist primarily of cash and cash equivalents and accounts receivables. The Company’s cash is primarily held with major banks and financial institutions throughout the world. At times, cash balances may be in excess of the amount insured. The Company is involved in a significant volume of contracts with the United States federal government and state and local governments. Approximately 59 %, 55 %, and 53 % of consolidated revenues for the years ended December 31, 2024, December 31, 2023 and December 31, 2022, respectively, and approximately 23 % and 18 % of accounts receivable as of December 31, 2024 and December 31, 2023, respectively were derived from contracts with the United States federal government. No other customers represented 10% or more of consolidated revenues or accounts receivable in any of the periods presented. Two customer sets within the United States federal government represent over 20% of total Company revenue for the year ended December 31, 2024. In order to mitigate the credit risk associated with customers, the Company performs periodic credit evaluations of its customers’ financial condition.
Property and Equipment	Property and Equipment Property and equipment are stated at cost and are shown net of accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets. Depreciation of leasehold improvements is computed using the straight-line method over the shorter of their estimated useful lives or the remaining term of the lease. The cost of assets retired or otherwise disposed of and the related accumulated depreciation are eliminated from the accounts, and any gain or loss thereon is included in net income. Expenditures for maintenance and repairs are expensed as incurred. Property and equipment are reviewed for impairment when events or circumstances change that indicate they may not be recoverable. Impairment losses are recognized when estimated future cash flows expected to result from the use of the assets and their eventual disposition are less than their carrying amount, in which case the asset is written down to its fair value.
Leases	Leases The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease ROU assets and current and long-term operating lease liabilities in the consolidated balance sheets. Finance leases are included in other noncurrent assets, accrued expenses and other current liabilities and other long-term liabilities in the consolidated balance sheets. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As most of the Company’s leases do not provide an implicit rate, incremental borrowing rates are used based on the information available at commencement date in determining the present value of lease payments. The operating lease ROU asset also includes any lease payments made and excludes lease incentives. Lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. We have lease agreements with lease and non-lease components where the lease consideration is allocated between the components based on relative standalone prices. For real property leases, allocations of lease consideration between lease and non-lease components are immaterial. For certain equipment leases, such as vehicles, we account for the lease and non-lease components as a single lease component. Additionally, for certain equipment leases, we apply a portfolio approach to effectively account for the operating lease ROU assets and liabilities.
Equity-Based Compensation	Equity-Based Compensation The Company measures the value of services received from employees and directors in exchange for an equity-based award based on the grant date fair value. The Company issues equity-based awards that settle in shares of the Company’s common stock. Awards containing performance measures are adjusted at each reporting period for the number of shares expected to be earned. Compensation cost for performance awards are trued-up at each reporting period for the number of shares expected to be earned pro-rated for the portion of the requisite service period rendered. The Company recognizes compensation costs for these awards on either a straight-line or accelerated basis over the vesting period of the award in selling, general and administrative expense in the consolidated statements of income. For awards that include market conditions, the grant date fair value is determined using a Monte Carlo simulation.
Business Combinations	Business Combinations The Company accounts for business combinations using the acquisition method, under which the purchase price of an acquired company is allocated to the tangible and intangible assets acquired and the liabilities assumed on the basis of their fair values at the date of acquisition. Any excess of purchase price over the fair value of tangible and intangible assets acquired and liabilities assumed is allocated to goodwill. The determination of fair values of assets acquired and liabilities assumed requires the Company to make estimates and use valuation techniques when a market value is not readily available. In determining the fair value of acquired intangible assets from our business acquisitions, the Company uses the multi-period excess earnings method to value customer relationships and backlog and values developed technologies using the relief-from royalty method. The Company’s determination of the fair value of the intangible assets acquired involves the use of significant estimates and assumptions related to discount rates, revenue growth rates, projected margins, and customer revenue attrition rates. Certain business acquisitions include contingent consideration. Contingent consideration is recorded at its fair value, using a Black-Scholes model, within other liabilities or other long-term liabilities, as appropriate. The fair value of contingent consideration involves the use of significant estimates and assumptions related to risks associated with earnout, i.e. risk in the underlying metric, risk in the earnout structure, counterparty credit risk, projected revenue, the revenue discount rate, the revenue volatility, and the Company's credit adjusted discount rate. Subsequent adjustments to these assumptions can cause changes to the measure of contingent consideration. The Company adjusts the preliminary purchase price allocation, as necessary, during the measurement period of up to one year after the acquisition closing date as the Company obtains more information as to facts and circumstances existing at the acquisition date. Acquisition-related costs are recognized separate from the acquisition and are expensed as incurred.
Consolidation of Joint Ventures and Variable Interest Entities	Consolidation of Joint Ventures and Variable Interest Entities The Company participates in joint ventures, which include partnerships and partially owned limited liability corporations, to bid, negotiate and complete specific projects. The Company is required to consolidate these joint ventures if it holds the majority voting interest or if the joint venture is determined to be a variable interest entity (“VIE”) for which the Company is the primary beneficiary, as described below. A VIE is an entity with one or more of the following characteristics: (a) the total equity investment at risk is not sufficient to permit the entity to finance its activities without additional financial support; (b) as a group, the holders of the equity investment at risk lack the ability to make certain decisions, the obligation to absorb expected losses or the right to receive expected residual returns; or (c) an equity investor has voting rights that are disproportionate to its economic interest and substantially all of the entity’s activities are on behalf of the investor with disproportionately low voting rights. The Company’s VIEs may be funded through contributions, loans and/or advances from the joint venture partners or by advances and/or letters of credit provided by clients. Certain VIEs are directly governed, managed, operated and administered by the joint venture partners. Others have no employees and, although these entities own and hold the contracts with the clients, the services required by the contracts are typically performed by the joint venture partners or by other subcontractors. The Company is considered the primary beneficiary and required to consolidate a VIE if it has the power to direct the activities that most significantly impact that VIE’s economic performance, and the obligation to absorb losses or the right to receive benefits of that VIE that could potentially be significant to the VIE. In determining whether the Company is the primary beneficiary, significant assumptions and judgments include the following: (1) identifying the significant activities and the parties that have the power to direct them; (2) reviewing the governing board composition and participation ratio; (3) determining the equity, profit and loss ratio; (4) determining the management-sharing ratio; (5) reviewing employment terms; and (6) reviewing the funding and operating agreements. Examples of significant activities currently being performed by the Company’s significant consolidated and unconsolidated joint ventures include engineering and design services; management consulting services; procurement and construction services; program management; construction management; and operations and maintenance services. If the Company determines that the power to direct the significant activities is shared by two or more joint venture parties, then there is no primary beneficiary and no party consolidates the VIE. In making the shared-power determination, the Company analyzes the key contractual terms, governance, related party and de facto agency as they are defined in the accounting standard, and other arrangements.
Goodwill	Goodwill The Company performs a goodwill impairment test annually, on October 1 st of each year and additionally, performs a quarterly qualitative assessment to address whether a triggering event has occurred that would require an impairment test in the interim period. For purposes of impairment testing, goodwill is allocated to the applicable reporting units based on the current reporting structure. Reporting units are operating segments or components of operating segments where discrete financial information is available and segment management regularly reviews the operating results. When evaluating goodwill for impairment, the Company may decide to first perform a qualitative assessment, or “step zero” impairment test, to determine whether it is more likely than not that impairment has occurred. If the Company does not perform a qualitative assessment, or if the Company determines that it is not more likely than not that the fair value of its reporting units exceeds their carrying amounts, the Company performs a quantitative assessment and calculates the estimated fair value of the respective reporting unit. If the carrying amount of a reporting unit exceeds its fair value, an impairment loss is recognized in the amount the carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The Company’s decision to perform a qualitative impairment assessment in a given year is influenced by a number of factors, including the significance of the excess of the Company’s estimated fair value over carrying value at the last quantitative assessment date, the amount of time in between quantitative fair value assessments, and the date of its acquisitions, if any.
Intangible Assets	Intangible Assets Intangible assets with finite lives arise from business acquisitions and are amortized based on the period over which the contractual or economic benefit of the intangible assets are expected to be realized or on a straight-line basis over the useful lives of the underlying assets, ranging from one to sixteen years . These primarily consist of customer relationships, developed technology, backlog, and covenants not to compete. When indicators of a potential impairment exist, the Company assesses the recoverability of the unamortized balance of its intangible assets by first comparing undiscounted expected cash flows associated with the asset, or the asset group they are part of, to its carrying value. Should the review indicate that the carrying value is not fully recoverable, the excess of the carrying value over the fair value of the intangible assets would be recognized as an impairment loss.
Income Taxes	Income Taxes Income taxes are accounted for under the asset and liability method. This approach requires the recognition of deferred tax liabilities and assets to reflect the tax effects of temporary differences between the financial statement carrying amounts and tax basis of the Company’s assets and liabilities. Deferred tax assets and liabilities are measured using enacted tax rates expected to be in effect when the asset or liability is recovered or settled. The effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date. Deferred tax assets are evaluated for future realization and valuation allowances are established when, in our opinion, it is more likely than not that all or some portion of the asset will not be realized. The Company recognizes the effect of income tax positions only if those positions are more likely than not of being sustained on examination by the taxing authorities based on the technical merits of the position. The tax benefits recognized in the financial statements on a particular tax position are measured based on the largest benefit that is greater than 50 percent likely of being realized. The amount of unrecognized tax benefits (“UTB”) is adjusted as appropriate for changes in facts and circumstances, such as significant amendments to existing tax law, new regulations or interpretations by the taxing authorities, new information obtained during a tax examination, or resolution of an examination. The Company recognizes both accrued interest and penalties, where appropriate, related to UTBs in income tax expense.
Foreign Currency Translation	Foreign Currency Translation The Company’s reporting currency is the U.S. Dollar. The functional currency of the Company’s foreign entities is typically the currency of the primary environment in which they operate. For foreign entities whose functional currency is not the U.S. dollar, the assets and liabilities are translated based on exchange rates in effect at the balance sheet date, while the income and expense accounts are translated using the average exchange rates during the period. Translation gains or losses, net of income tax effects, are reflected in accumulated other comprehensive income on the consolidated balance sheets. Transaction gains and losses due to movements in exchange rates between the functional currency and the currency in which a foreign currency transaction is denominated are recognized as “Other income (expense), net” in the Company’s consolidated statements of income.
Self-Insurance	Self-Insurance The Company typically utilizes third-party insurance subject to varying retention levels or self-insurance. The Company is self-insured for a portion of the losses and liabilities primarily associated with workers’ compensation, general, professional, automobile, employee matters, certain medical plans, and project-specific liability claims. Losses are accrued based upon the Company’s estimates of the aggregate liability for claims incurred using historical experience and certain actuarial assumptions, as provided by an independent actuary. The estimate of self-insurance liability includes an estimate of incurred but not reported claims, based on data compiled from historical experience.
New Accounting Pronouncements	New Accounting Pronouncements In the fourth quarter of 2024, The Financial Accounting Standards Board ("FASB") Issued Accounting Standards Update (“ASU”) 2024-04, "Debt—Debt with Conversion and Other Options (Subtopic 470-20)" ("ASU 2024-04"). ASU 2024-04 improves the relevance and consistency in application of the induced conversion guidance in Subtopic 470-20, Debt– Debt with Conversion and Other Options . The amendments in ASU 2024-04 clarify the requirements for determining whether certain settlements of convertible debt instruments should be accounted for as an induced conversion. Under the amendments, to account for a settlement of a convertible debt instrument as an induced conversion, an inducement offer is required to provide the debt holder with, at a minimum, the consideration (in form and amount) issuable under the conversion privileges provided in the terms of the instrument. The amendments in this Update are effective for all entities for annual reporting periods beginning after December 15, 2025, and interim reporting periods within those annual reporting periods. Early adoption is permitted for all entities that have adopted the amendments in ASU 2020-06. The Company adopted ASU 2020-06 in the first quarter of 2021. The Company has elected to early adopt ASU 2024-04 as of January 1, 2024 on a prospective basis. The adoption of this ASU had a material impact on the Company's consolidated financial statements. In the first quarter of 2024, the Company took an extinguishment charge related to the partial repurchase of Convertible Senior Notes due 2025. This repurchase was recorded in the Company's financial statements as a loss on debt extinguishment according to the applicable guidance prior to ASU 2024-04. With the early adoption of ASU 2024-04, the Company reassessed the accounting conclusion of the first quarter 2024 partial repurchase of Convertible Senior Notes due 2025 and concluded the partial repurchase is subject to inducement accounting under ASU 2024-04. Under inducement accounting, the difference in the fair value of the securities issuable pursuant to conversion privileges compared to the fair value of the consideration paid on the date of the acceptance of the inducement offer is recorded to inducement expense. The difference in the consideration paid to note holders, less inducement expenses, less the fair value of the notes repurchased is charged to equity. For the year ended December 31, 2024, the Company reversed the loss on extinguishment of debt for the partial repurchase of the Convertible Senior Notes due 2025 and recorded the repurchase transaction as an induced conversion. This change from extinguishment to inducement accounting resulted in the Company (i.) reversing the $ 211.0 million loss and the related $ 49.9 million tax benefit on extinguishment of debt, recorded in Q1 2024, (ii.) recording a $ 18.4 million convertible debt repurchase loss , (iii.) the difference between the extinguishment loss and inducement expense of $ 192.6 million recorded to equity, and (iv.) the related tax benefit of $ 45.6 million recorded to equity. See "Note 11—D ebt and Credit Facilities" for a further discussion of the first quarter 2024 extinguishment accounting and subsequent change to inducement accounting. Also see "Note 21—Quarterly Information " for the quarterly financial statement impacts related to this accounting change. In the fourth quarter of 2024, The FASB Issued ASU 2024-03 "Income Statement—Reporting Comprehensive Income—Expense Disaggregation Disclosures (Subtopic 220-40)" (ASU 2024-03"). ASU 2024-03 requires disclosure, in the notes to financial statements, of specified information about certain costs and expenses. ASU 2024-03 is effective for annual reporting periods beginning after December 15, 2026, and interim reporting periods beginning after December 15, 2027. Early adoption is permitted. The adoption of this ASU will not have a material impact on the Company's consolidated financial statements. In the fourth quarter of 2023, The FASB Issued Accounting Standards Update (“ASU”) 2023-09, "Income Taxes (Topic 740)" ("ASU 2023-09"). ASU 2023-09 enhances the transparency and decision usefulness of income tax disclosures. The amendments in ASU 2023-09 addresses investor requests for more transparency about income tax information through improvements to income tax disclosures primarily related to the rate reconciliation and income taxes paid information. ASU 2023-09 also includes certain other amendments to improve the effectiveness of income tax disclosures. ASU 2023-09 is effective for fiscal years beginning after December 15, 2024. Early adoption is permitted. The adoption of this ASU will not have a material impact on the Company's consolidated financial statements. In the fourth quarter of 2023, The FASB Issued ASU 2023-07, "Segment Reporting (Topic 280)". ASU 2023-07 introduces enhanced disclosures about significant segment expenses along with other enhanced segment disclosures. ASU 2023-07 is effective for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption is permitted. The adoption of this ASU did no t have a material impact on the Company's consolidated financial statements. During July 2023, the FASB Issued ASU 2023-03. ASU 2023-03 incorporates, into certain accounting standards, amendments to SEC paragraphs pursuant to SEC Staff Accounting Bulletin No. 120, SEC Staff Announcement at the March 24, 2022 EITF meeting, and Staff Accounting Bulletin Topic 6.B, Accounting Series Release 280—General Revisions of Regulation S-X: Income or Loss Applicable to Common Stock. These rules are effective immediately. The adoption of this ASU will not have a material impact on the Company's consolidated financial statements. In the first quarter of 2022 , the Company early adopted ASU 2021-08, “Business Combinations (Topic 805) ("ASU 2021-08"): Accounting for Contract Assets and Contract Liabilities from Contracts with Customers”. The new guidance requires that the approach of ASC 606, Revenue from Contracts with Customers, should be used to measure an acquired revenue contract in a business combination. This guidance is to be applied (1) retrospectively to all business combinations for which the acquisition date occurs on or after the beginning of the fiscal year that includes the interim period of early application and (2) prospectively to all business combinations that occur on or after the date of initial application. The early adoption of ASU 2021-08 did no t have a material impact on the Company's consolidated financial statements.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2024
BCC Engineering, LLC
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Purchase Price Allocation	The following table summarizes the acquisition date fair value of the purchase consideration transferred (in thousands): Amount Cash and cash equivalents $ 2,839 Accounts receivable 24,142 Contract assets 16,649 Prepaid expenses and other current assets 2,483 Right of use assets, operating leases 9,438 Property and Equipment 1,586 Other noncurrent assets 1,743 Goodwill 174,532 Intangible assets 32,400 Accounts payable ( 8,668 ) Accrued expenses and other current liabilities ( 7,236 ) Contract liabilities ( 4,446 ) Short-term lease liabilities, operating leases ( 1,977 ) Deferred income taxes ( 2,203 ) Long-term lease liabilities, operating leases ( 7,462 ) Other long-term liabilities ( 1,155 ) Net assets acquired $ 232,665
Schedule of Intangible Assets Value on Purchase Price	Of the total purchase price, the following values were preliminarily assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships $ 6,500 4 Backlog 23,400 4 Non-compete agreements 1,700 3 Other $ 800 1
Schedule of Supplemental Pro Forma Information	Supplemental information of unaudited pro forma operating results assuming the BCC acquisition had been consummated as of the beginning of fiscal year 2023 (in thousands) is as follows: 2024 2023 (unaudited) (unaudited) Pro forma Revenue $ 6,838,190 $ 5,537,090 Pro forma Net Income including noncontrolling interests 286,948 189,200
BlackSignal Technologies, LLC.
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Purchase Price Allocation	The following table summarizes the acquisition date fair value of the purchase consideration transferred (in thousands): Amount Cash and cash equivalents $ 4,917 Accounts receivable 5,171 Contract assets 3,209 Prepaid expenses and other current assets 447 Right of use assets, operating leases 5,370 Property and Equipment 997 Goodwill 119,663 Intangible assets 97,600 Other assets 145 Accounts payable ( 951 ) Accrued expenses and other current liabilities ( 4,999 ) Short-term lease liabilities, operating leases ( 800 ) Deferred income taxes ( 22,461 ) Long-term lease liabilities, operating leases ( 4,570 ) Net assets acquired $ 203,738
Schedule of Intangible Assets Value on Purchase Price	Of the total purchase price, the following values were preliminarily assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships $ 73,900 14 Backlog 11,700 3 Developed technologies 5,200 5 Non-compete agreements 6,100 3 Other $ 700 1
Schedule of Supplemental Pro Forma Information	Supplemental information of unaudited pro forma operating results assuming the BlackSignal acquisition had been consummated as of the beginning of fiscal year 2023 (in thousands) is as follows: 2024 2023 (unaudited) (unaudited) Pro forma Revenue $ 6,782,552 $ 5,481,036 Pro forma Net Income including noncontrolling interests 283,900 185,954
Sealing Technologies, Inc.
Schedule of Acquisition Date Fair Value of the Purchase Consideration Transferred	The following table summarizes the acquisition date fair value of the purchase consideration transferred (in thousands): Amount Cash paid at closing $ 176,028 Fair value of contingent consideration to be achieved 3,231 Total purchase price $ 179,259
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Purchase Price Allocation	The following table summarizes the estimated fair values of the assets acquired and liabilities assumed based on the purchase price allocation as of the date of acquisition (in thousands): Amount Cash and cash equivalents $ 8,133 Accounts receivable 17,889 Contract assets 2,946 Prepaid expenses and other current assets 1,379 Property and equipment 2,025 Right of use assets, operating leases 1,836 Deferred tax assets 357 Goodwill 90,593 Intangible assets 75,000 Accounts payable ( 15,987 ) Accrued expenses and other current liabilities ( 2,408 ) Contract liabilities ( 668 ) Short-term lease liabilities, operating leases ( 418 ) Long-term lease liabilities, operating leases ( 1,418 ) Net assets acquired $ 179,259
Schedule of Intangible Assets Value on Purchase Price	Of the total purchase price, the following values were preliminarily assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships $ 40,000 14 Backlog 26,000 3 Developed technologies 8,000 3 Other $ 1,000 1
Schedule of Supplemental Pro Forma Information	Supplemental information of unaudited pro forma operating results assuming the SealingTech acquisition had been consummated as of the beginning of fiscal year 2022 (in thousands) is as follows: 2023 2022 (unaudited) (unaudited) Pro forma Revenue $ 5,525,099 $ 4,262,525 Pro forma Net Income including noncontrolling interests 216,157 107,937
IPKeys Power Partners
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Purchase Price Allocation	The following table summarizes the estimated fair values of the assets acquired and liabilities assumed based on the purchase price allocation as of the date of acquisition (in thousands): Amount Cash and cash equivalents $ 126 Accounts receivable 3,937 Contract assets 834 Prepaid expenses and other current assets 455 Property and equipment 86 Right of use assets, operating leases 1,105 Other noncurrent assets 152 Goodwill 22,407 Intangible assets 23,000 Accounts payable ( 541 ) Accrued expenses and other current liabilities ( 1,768 ) Contract liabilities ( 1,936 ) Short-term lease liabilities, operating leases ( 343 ) Deferred tax liabilities ( 3,713 ) Long-term lease liabilities, operating leases ( 762 ) Net assets acquired $ 43,039
Schedule of Intangible Assets Value on Purchase Price	Of the total purchase price, the following values were assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships (1) $ 15,900 16 Developed technologies 7,000 11 Other $ 100 1 (1) The acquired business is a SaaS commercial business. Backlog for this type of business is included as customer relationships.
Schedule of Supplemental Pro Forma Information	Supplemental information of unaudited pro forma operating results assuming the IPKeys acquisition had been consummated as of the beginning of fiscal year 2022 (in thousands) is as follows: 2023 2022 (unaudited) (unaudited) Pro forma Revenue $ 5,445,604 $ 4,207,967 Pro forma Net Income including noncontrolling interests 209,773 123,257
Xator Corporation
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Purchase Price Allocation	The following table summarizes the estimated fair values of the assets acquired and liabilities assumed based on the purchase price allocation as of the date of acquisition (in thousands): Amount Cash and cash equivalents $ 8,935 Accounts receivable 7,393 Contract assets 24,332 Prepaid expenses and other current assets 3,615 Property and equipment 1,699 Right of use assets, operating leases 7,517 Goodwill 257,934 Investments in and advances to unconsolidated joint ventures 698 Intangible assets 123,500 Other noncurrent assets 9,156 Accounts payable ( 6,626 ) Accrued expenses and other current liabilities ( 31,309 ) Contract liabilities ( 2,631 ) Short-term lease liabilities, operating leases ( 2,371 ) Long-term lease liabilities, operating leases ( 5,146 ) Other long-term liabilities ( 9,156 ) Net assets acquired $ 387,540
Schedule of Intangible Assets Value on Purchase Price	Of the total purchase price, the following values were assigned to intangible assets (in thousands, except for years): Gross Amortization (in years) Customer relationships $ 37,000 15 Backlog 81,000 6 Trade name 4,000 1 Developed technologies 1,000 3 Non-compete agreements $ 500 3
Schedule of Supplemental Pro Forma Information	Supplemental information of unaudited pro forma operating results assuming the Xator acquisition had been consummated as of the beginning of fiscal year 2021 (in thousands) is as follows: 2022 2021 (unaudited) (unaudited) Pro forma Revenue $ 4,302,448 $ 3,949,562 Pro forma Net Income including noncontrolling interests 139,901 91,770

Contracts with Customers (Table

Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2024
Disaggregation of Revenue [Line Items]
Summary of Disaggregation of Revenue	The Company’s contracts contain both fixed price and cost reimbursable components. Contract types are based on the component that represents the majority of the contract. The following table presents revenue disaggregated by contract type (in thousands): December 31, December 31, December 31, Fixed-price $ 2,844,719 $ 1,810,499 $ 1,138,482 Time-and-Materials 1,419,168 1,352,871 1,166,548 Cost-plus 2,486,689 2,279,379 1,890,242 Total $ 6,750,576 $ 5,442,749 $ 4,195,272
Summary of Contract Assets and Contract Liabilities	Contract assets and contract liabilities balances at December 31, 2024 and December 31, 2023 were as follows (in thousands): December 31, 2024 December 31, 2023 $ change % change Contract assets $ 741,504 $ 757,515 $ ( 16,011 ) - 2.1 % Contract liabilities 289,799 301,107 ( 11,308 ) - 3.8 % Net contract assets (liabilities) (1) $ 451,705 $ 456,408 $ ( 4,703 ) - 1.0 % (1) Total contract retentions included in net contract assets (liabilities) were $ 89.8 million as of December 31, 2024, of which $ 35.9 million are not expected to be paid in 2025. Total contract retentions included in net contract assets (liabilities) were $ 73.8 million as of December 31, 2023. Contract assets at December 31, 2024 and December 31, 2023 include approximately $ 70.7 million and $ 109.5 million, respectively, related to net claim recovery estimates. For the year ended December 31, 2024 there was a $ 21.6 million loss recognized related to the collectability of claims. For the year ended December 31, 2023 , there were no material losses recognized related to the collectability of claims.
Summary of Changes in Contract Assets and Contract Liabilities	Certain changes in contract assets and contract liabilities consisted of the following: December 31, 2024 December 31, 2023 Acquired contract assets $ 19,858 $ 2,715 Acquired contract liabilities 4,446 3,155
Summary of Changes in Revenue	Revisions in estimates, such as changes in estimated claims or incentives, related to performance obligations partially satisfied in previous periods that individually had an impact of $ 5 million or more on revenue resulted in the following changes in revenue. 2024 2023 2022 Revenue impact, net $ ( 55,952 ) $ 5,428 $ -
Summary of Finanial Statement Impact from Revisions in Estimates	Certain financial statement impacts from revisions in estimates were as follows (in thousands): December 31, 2024 December 31, 2023 December 31, 2022 Operating income (loss) $ ( 62,298 ) $ 35,297 $ — Net income (loss) ( 47,651 ) 26,261 — Diluted earnings (loss) per share $ ( 0.42 ) $ 0.23 $ - The amounts for 2024, in the table above, include the impact from a contract in the Critical Infrastructure segment related to a change in estimate increasing direct costs of contracts by $ 6.3 million. The amounts for 2023, in the table above, include the impact from contracts in the Critical Infrastructure segment related to a change in estimate increasing direct costs of contracts by $ 8.0 million related to net write-downs and a decrease in direct costs of contracts of $ 37.9 million related to a legal matter. These impacts do not include the operating income impacts disclosed below in "Note 16— Investments in and Advances to Joint Ventures.
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Billed $ 712,046 $ 646,375 Unbilled 392,236 273,215 Total accounts receivable, gross 1,104,282 919,590 Allowance for doubtful accounts ( 3,886 ) ( 3,952 ) Total accounts receivable, net $ 1,100,396 $ 915,638
Summary of Remaining Unsatisfied Performance Obligations Expect to Satisfy	The Company expects to satisfy its RUPO as of December 31, 2024 over the following periods (in thousands): Period RUPO Will Be Satisfied Within One Year Within One to Two Years Thereafter Federal Solutions $ 1,815,751 $ 439,216 $ 142,994 Critical Infrastructure 2,062,055 1,099,765 1,174,217 Total $ 3,877,806 $ 1,538,981 $ 1,317,211

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2024
Leases [Abstract]
Summary of Lease Costs	The components of lease costs for the years ended December 31, 2024 and December 31, 2023 are as follows (in thousands): 2024 2023 Operating lease cost $ 64,858 $ 67,181 Short-term lease cost 17,114 13,782 Amortization of right-of-use assets 3,549 2,699 Interest on lease liabilities 434 273 Sublease income ( 4,289 ) ( 4,718 ) Total lease cost $ 81,666 $ 79,217
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases for the years ended December 31, 2024 and December 31, 2023 is as follows (in thousands): 2024 2023 Operating cash flows for operating leases $ 67,696 $ 71,432 Operating cash flows for finance leases 434 273 Financing cash flows for finance leases 3,376 2,618 Right-of-use assets obtained in exchange for new 36,583 62,856 Right-of-use assets obtained in exchange for new $ 4,220 $ 6,456
Schedule of Supplemental Balance Sheet and Other Information Related to Leases	Supplemental balance sheet and other information related to leases as of December 31, 2024 and December 31, 2023 is as follows (in thousands): 2024 2023 Operating Leases: Right-of-use assets $ 153,048 $ 159,211 Lease liabilities: Current $ 52,725 $ 58,556 Long-term 114,386 117,505 Total operating lease liabilities $ 167,111 $ 176,061 Finance Leases: Other noncurrent assets $ 9,864 $ 7,779 Accrued expenses and other current liabilities $ 3,645 $ 2,682 Other long-term liabilities $ 6,441 $ 5,129 Weighted Average Remaining Lease Term: Operating leases 3.9 Years 3.9 Years Finance leases 2.8 Years 3.1 years Weighted Average Discount Rate: Operating leases 4.5 % 4.2 % Finance leases 5.0 % 4.6 %
Schedule of Maturity Analysis of Future Undiscounted Cash Flows	A maturity analysis of the future undiscounted cash flows associated with the Company’s operating and finance lease liabilities as of December 31, 2024 is as follows (in thousands): Operating Finance 2025 $ 59,839 $ 4,217 2026 42,669 3,492 2027 29,744 2,236 2028 24,383 933 2029 18,341 92 Thereafter 7,682 - Total lease payments 182,658 10,970 Less: imputed interest ( 15,547 ) ( 884 ) Total present value of lease liabilities $ 167,111 $ 10,086

Employee Stock Purchase and E_2

Employee Stock Purchase and Equity-Based Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2024
Schedule of Share Based Compensation Plans Under Equity Securities Authorized for Issuance	The following table provides information as of December 31, 2024 regarding compensation plans under which our equity securities are authorized for issuance. Plan Category Number of Securities to be Issued upon Exercise of Outstanding Options, Warrants and Rights Weighted-Average Exercise Price of Outstanding Options, Warrants and Rights Number of Securities Remaining Available for Future Issuance under Equity Compensation Plans (Excluding Securities Reflected in Column (a)) Equity compensation plans approved by security holders (1) - - 1,367,785 (2) Equity compensation plans not approved by security holders 1,883,018 (3) - 7,651,085 (4) Total 1,883,018 - 9,018,870 (1) Consists of the 2020 Employee Stock Purchase Plan. (2) Amount represents 1,367,785 shares remaining available for future issuance under the 2020 Employee Stock Purchase Plan (of which 47,860 shares were purchased pursuant to the offering period that ended on December 31, 2024). (3) Amount represents the sum of 1,883,018 shares of common stock subject to outstanding RSU and PSU awards under the 2019 Incentive Plan (with PSU awards reflected at “target” levels), (4) Amount represents 7,651,085 shares remaining available for future issuance under the 2019 Incentive Plan.
Summary of Stock Issuance Activity	The following table presents stock issuance activity for the years ended December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Purchase price paid for shares sold $ 7,935 $ 6,059 Number of shares sold 96 117
Summary of Restricted Stock Outstanding	The following table presents the number of shares of restricted stock outstanding (at target shares for awards with performance conditions) at December 31, 2024, December 31, 2023 and December 31, 2022: December 31, December 31, December 31, Restricted Stock Units (service condition) 911,908 1,085,203 817,278 Restricted Stock Units (service and performance condition) 971,110 1,008,133 803,877
Restricted Stock Units
Summary of Restricted Stock Unit Activity	The following table presents the number and weighted average grant-date fair value of restricted stock units (at target shares for awards with performance conditions) for the years ended December 31, 2024, December 31, 2023 and December 31, 2022: Number of Units Weighted Average Grant-Date Fair Value Outstanding at December 31, 2021 1,359,243 $ 36.75 Granted 1,068,620 37.42 Vested ( 497,200 ) 35.86 Forfeited ( 309,508 ) 36.28 Outstanding at December 31, 2022 1,621,155 37.49 Granted 1,068,516 48.96 Vested ( 372,962 ) 37.56 Forfeited ( 223,373 ) 39.90 Outstanding at December 31, 2023 2,093,336 43.11 Granted 642,996 79.71 Vested ( 697,956 ) 37.83 Forfeited ( 155,358 ) 45.33 Outstanding at December 31, 2024 1,883,018 $ 57.35
Summary of Restricted Stock Outstanding	The following table presents the number of shares of restricted stock units granted (at target shares for awards with performance conditions) for the years ended December 31, 2024, December 31, 2023 and December 31, 2022: December 31, December 31, December 31, Restricted Stock Units (service condition) 346,483 616,337 666,184 Restricted Stock Units (service and performance condition) 296,513 452,179 402,436

Goodwill (Tables)

Goodwill (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Changes in Carrying Value of Goodwill by Reporting Segment	The following table summarizes the changes in the carrying value of goodwill by reporting segment for the years ended December 31, 2024 and December 31, 2023 (in thousands): December 31, Acquisitions Foreign December 31, Federal Solutions $ 1,686,901 $ 119,663 $ - $ 1,806,564 Critical Infrastructure 105,764 174,585 ( 4,233 ) 276,116 Total $ 1,792,665 $ 294,248 $ ( 4,233 ) $ 2,082,680 December 31, Acquisitions Foreign December 31, Federal Solutions $ 1,591,563 $ 95,338 $ - $ 1,686,901 Critical Infrastructure 70,287 34,261 1,216 105,764 Total $ 1,661,850 $ 129,599 $ 1,216 $ 1,792,665

Intangible Assets (Tables)

Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2024
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Gross Amount and Accumulated Amortization of Intangible Assets	The gross amount and accumulated amortization of acquired identifiable intangible assets included in “Intangible assets, net” on the consolidated balance sheets were as follows (in thousands except for years): December 31, 2024 December 31, 2023 Weighted Gross Accumulated Net Gross Accumulated Net Amortization (in years) Backlog $ 142,100 $ ( 51,322 ) $ 90,778 $ 130,000 $ ( 45,964 ) $ 84,036 4.5 Customer relationships 372,930 ( 139,568 ) 233,362 297,120 ( 124,194 ) 172,926 11.6 Leases - - - 120 ( 106 ) 14 - Developed technology 23,200 ( 7,458 ) 15,742 31,600 ( 15,823 ) 15,777 4.6 Trade name 1,500 ( 367 ) 1,133 1,000 ( 417 ) 583 1.0 Non-compete agreements 8,300 ( 1,203 ) 7,097 1,500 ( 1,097 ) 403 3.0 In process research and development 1,800 - 1,800 1,800 - 1,800 n/a Other intangibles 25 - 25 375 ( 348 ) 27 n/a Total intangible assets $ 549,855 $ ( 199,918 ) $ 349,937 $ 463,515 $ ( 187,949 ) $ 275,566
Schedule of Estimated Amortization Expense	Estimated amortization expense in each of the next five years and beyond is as follows (in thousands): December 31, 2024 2025 $ 64,871 2026 57,313 2027 50,759 2028 36,871 2029 22,659 Thereafter 115,639 Total $ 348,112

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	12 Months Ended
	Dec. 31, 2024
Property, Plant and Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment consisted of the following at December 31, 2024 and December 31, 2023 (in thousands): December 31, 2024 December 31, 2023 Useful life Buildings and leasehold improvements $ 103,945 $ 102,372 1 - 15 Furniture and equipment 84,720 84,244 3 - 10 Computer systems and equipment 172,437 168,926 3 - 10 Construction equipment 6,463 6,173 5 - 7 Construction in progress 30,342 21,030 397,907 382,745 Accumulated depreciation ( 286,332 ) ( 283,788 ) Property and equipment, net $ 111,575 $ 98,957

Accrued Expenses and Other Cu_2

Accrued Expenses and Other Current Liabilities (Tables)	12 Months Ended
	Dec. 31, 2024
Payables and Accruals [Abstract]
Schedule of Accrued Expenses and Other Current Liabilities	Accrued expenses and other current liabilities consisted of the following at December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Salaries and wages $ 119,122 $ 102,779 Employee benefits 371,435 342,707 Self-insurance liability 17,723 24,193 Project cost accruals 307,200 254,070 Other accrued expenses 78,945 77,674 Total accrued expenses and other current liabilities $ 894,425 $ 801,423

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	12 Months Ended
	Dec. 31, 2024
Debt Disclosure [Abstract]
Schedule of Debt	Debt consisted of the following at December 31, 2024 and December 31, 2023 (in thousands): December 31, 2024 December 31, 2023 Short-Term Debt: Delayed draw term loan $ 350,000 $ - Convertible senior notes due 2025 113,405 - Total Short-Term Debt 463,405 - Long-Term Debt: Delayed draw term loan - 350,000 Convertible senior notes due 2025 - 400,000 Convertible senior notes due 2029 800,000 - Revolving credit facility - - Debt issuance costs ( 15,904 ) ( 4,037 ) Total Long-Term Debt 784,096 745,963 Total Debt $ 1,247,501 $ 745,963

Other Long-term Liabilities (Ta

Other Long-term Liabilities (Tables)	12 Months Ended
	Dec. 31, 2024
Other Liabilities Disclosure [Abstract]
Schedule of Other Long-term Liabilities	Other long-term liabilities consisted of the following at December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Self-insurance liability $ 58,878 $ 81,795 Reserve for uncertain tax positions 22,985 22,815 Finance lease obligations 6,441 5,129 Other long-term liabilities 8,182 10,556 Total other long-term liabilities $ 96,486 $ 120,295

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2024
Income Tax Disclosure [Abstract]
Components of Income from Operations Before Income Taxes	The following table presents the components of our income from operations before income taxes (in thousands): 2024 2023 2022 United States earnings $ 256,210 $ 179,522 $ 77,110 Foreign earnings 111,441 84,531 89,112 $ 367,651 $ 264,053 $ 166,222
Schedule of Income Tax Expense (Benefit) Attributable to Income from Continuing Operations	The income tax expense (benefit) attributable to income from operations for the years ended December 31, 2024, December 31, 2023, and December 31, 2022 consists of the following (in thousands): 2024 2023 2022 Current Federal $ 37,713 $ 37,699 $ 21,323 State 13,441 13,340 9,946 Foreign 19,731 14,013 9,232 Total current income tax expense 70,885 65,052 40,501 Deferred Federal 1,397 ( 5,974 ) ( 2,902 ) State 3,941 ( 590 ) ( 623 ) Foreign 763 ( 2,350 ) 2,681 Total deferred tax benefit 6,101 ( 8,914 ) ( 844 ) Total income tax expense $ 76,986 $ 56,138 $ 39,657
Computation of Income Tax Expense (Benefit)	Income tax expense (benefit) was different from the amount computed by applying the United States federal statutory rate to pre-tax income from continuing operations as a result of the following (in thousands): 2024 2023 2022 Income before income tax expense $ 367,651 $ 264,053 $ 166,222 Tax at federal statutory tax rate 77,207 21.0 % 55,451 21.0 % 34,907 21.0 % State taxes, net of federal tax benefit 11,852 3.2 % 9,807 3.7 % 7,530 4.5 % Change in valuation allowance 11,111 3.0 % 5,773 2.2 % 1,363 0.8 % Change in uncertain tax positions 3,584 1.0 % 3,530 1.3 % 1,688 1.0 % Foreign tax rate differential ( 6,078 ) - 1.7 % ( 6,258 ) - 2.4 % ( 1,787 ) - 1.1 % Tax cost of foreign operations, net of credits 1,842 0.5 % 3,085 1.2 % 777 0.5 % Foreign-derived intangible income deduction ( 14,794 ) - 4.0 % ( 4,736 ) - 1.8 % ( 76 ) 0.0 % Noncontrolling interests ( 11,679 ) - 3.2 % ( 9,821 ) - 3.7 % ( 6,279 ) - 3.8 % Federal business credits ( 2,932 ) - 0.8 % ( 2,731 ) - 1.0 % ( 1,926 ) - 1.2 % Executive compensation 7,351 2.0 % 1,636 0.6 % 1,921 1.2 % Equity compensation ( 7,170 ) - 2.0 % ( 158 ) - 0.1 % 10 0.0 % Other, net 6,692 1.8 % 560 0.2 % 1,529 0.9 % Total income tax expense $ 76,986 20.9 % $ 56,138 21.3 % $ 39,657 23.9 %
Components of Deferred Tax Assets and Liabilities	The components of deferred tax assets and liabilities consist of the following at December 31, 2024 and December 31, 2023 (in thousands): 2024 2023 Deferred tax assets Project and non-project reserves $ 23,184 $ 23,555 Employee compensation and benefits 76,944 69,726 Revenue and cost recognition 46,250 37,616 Insurance accruals 12,424 14,081 Net operating losses 17,640 8,663 Lease liabilities 42,572 44,626 Tax credit carryforwards 35,845 31,727 Other 17,432 3,285 Total deferred tax assets 272,291 233,279 Valuation allowance ( 45,318 ) ( 34,779 ) Total deferred tax assets 226,973 198,500 Deferred tax liabilities Intangible assets ( 57,361 ) ( 18,783 ) Right-of-use assets ( 38,605 ) ( 40,131 ) Profit remittance tax ( 6,842 ) ( 5,822 ) Other ( 1,758 ) ( 3,378 ) Total deferred tax liabilities ( 104,566 ) ( 68,114 ) Net deferred tax asset $ 122,407 $ 130,386 The Company is not asserting that any of the earnings of the foreign subsidiaries will be permanently reinvested. Therefore, the Company has recorded a deferred tax liability for the undistributed earnings net of applicable foreign tax credits.
Reconciliation of Beginning and Ending Balances of Unrecognized Tax Benefits	A reconciliation of the beginning and ending balances of unrecognized tax benefits is as follows (in thousands): 2024 2023 2022 Beginning of year $ 25,497 $ 22,798 $ 21,181 Increases—current year tax positions 1,058 3,220 4,666 Increases—prior year tax positions 7,488 2,458 2,254 Decreases—prior year tax positions ( 1,826 ) ( 1,589 ) ( 3,537 ) Settlements ( 1,334 ) ( 1,026 ) ( 1,447 ) Lapse of statute of limitations ( 1,345 ) ( 364 ) ( 319 ) End of year $ 29,538 $ 25,497 $ 22,798

Investments in and Advances t_2

Investments in and Advances to Joint Ventures (Tables)	12 Months Ended
	Dec. 31, 2024
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Financial Information of Consolidated Joint Ventures	The following represents financial information for consolidated joint ventures included in the consolidated financial statements as of and for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 (in thousands): 2024 2023 Current assets $ 519,450 $ 426,633 Noncurrent assets 9,841 14,295 Total assets 529,291 440,928 Current liabilities 296,774 260,286 Noncurrent liabilities 2,203 5,132 Total liabilities 298,977 265,418 Total joint venture equity $ 230,314 $ 175,510 2024 2023 2022 Revenue $ 788,702 $ 708,391 $ 483,888 Costs 676,258 613,186 422,559 Net income $ 112,444 $ 95,205 $ 61,329 Net income attributable to noncontrolling interests $ 55,612 $ 46,766 $ 29,901
Summary of Financial Information for Unconsolidated Joint Ventures	The following represents the financial information of the Company’s unconsolidated joint ventures as presented in their unaudited financial statements as of and for the years ended December 31, 2024, December 31, 2023 and December 31, 2022 (in thousands): 2024 2023 Current assets $ 1,477,950 $ 1,607,953 Noncurrent assets 431,476 483,693 Total assets 1,909,426 2,091,646 Current liabilities 947,072 1,057,113 Noncurrent liabilities 469,808 518,647 Total liabilities 1,416,880 1,575,760 Total joint venture equity $ 492,546 $ 515,886 Investments in and advances to unconsolidated joint $ 138,759 $ 128,204 2024 2023 2022 Revenue $ 2,118,799 $ 2,313,420 $ 2,406,407 Costs 2,108,768 2,310,114 2,325,472 Net income $ 10,031 $ 3,306 $ 80,935 Equity in (losses) earnings of unconsolidated joint ventures $ ( 23,361 ) $ ( 47,751 ) $ 16,347
Summary of Financial Statement Impact From Changes In Estimates on an Unconsolidated Joint Ventures	The following table presents certain financial statement impacts from changes in estimates on unconsolidated joint ventures in the Critical Infrastructure segment. 2024 2023 2022 Operating loss $ ( 51,715 ) $ ( 83,398 ) $ ( 13,817 ) Net loss ( 44,682 ) ( 61,842 ) ( 10,335 ) Diluted loss per share $ ( 0.40 ) $ ( 0.54 ) $ ( 0.09 )

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2024
Related Party Transactions [Abstract]
Schedule of Consolidated Balance Sheet Related to Services Provided to Unconsolidated Joint Ventures	Amounts included in the consolidated balance sheets related to services the Company provided to unconsolidated joint ventures are as follows (in thousands): 2024 2023 Accounts receivable $ 38,443 $ 38,898 Contract assets 11,540 38,009 Contract liabilities 10,776 15,287 Amounts presented above for comparable periods have been updated to reflect all unconsolidated joint ventures.

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 31, 2024
Fair Value Disclosures [Abstract]
Summay of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis	Financial assets and liabilities measured at fair value on a recurring basis are as follows: Fair value as of December 31, 2024 (in thousands): Level 1 Level 2 Level 3 Total Assets related to defined contribution plan Mutual funds $ 875 $ — $ — $ 875 Fixed income — 6,627 — 6,627 Cash and cash equivalents 349 — — 349 Total assets at fair value $ 1,224 $ 6,627 $ — $ 7,851 Fair value as of December 31, 2023 (in thousands): Level 1 Level 2 Level 3 Total Assets related to defined contribution plan Mutual funds $ 1,840 $ — $ — 1,840 Fixed income — 6,568 — 6,568 Cash and cash equivalents 355 — — 355 Total assets at fair value $ 2,195 $ 6,568 — $ 8,763 Contingent consideration Earnout liability $ - $ - $ 2,300 $ 2,300 Total liabilities at fair value $ - $ - $ 2,300 $ 2,300
Summary of Carrying Values and Estimated Fair Values Of Financial Instruments	The carrying values and estimated fair values of our financial instruments that are not required to be recorded at fair value in our consolidated balance sheets, on the basis of Level 1 inputs for the Company's convertible notes and Level 2 inputs for the delayed draw term loan, were as follows (in thousands): December 31, 2024 December 31, 2023 Carrying Value Fair Value Carrying Value Fair Value Liabilities: Convertible senior notes due 2025 $ 113,405 $ 233,206 $ 400,000 $ 568,000 Convertible senior notes due 2029 800,000 939,280 - - Delayed draw term loan 350,000 350,000 350,000 350,000 Total $ 1,263,405 $ 1,522,486 $ 750,000 $ 918,000

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2024
Earnings Per Share [Abstract]
Schedule of Numerator and Denominator used to Compute Basic and Diluted EPS	The following table reconciles the numerator and denominator used to compute basic and diluted EPS for the years ended December 31, 2024, December 31, 2023, and December 31, 2022 (in thousands): 2024 2023 2022 Numerator for Basic and Diluted EPS: Net income attributable to Parsons Corporation - basic $ 235,053 $ 161,149 $ 96,664 Convertible senior notes if-converted method interest adjustment 2,932 2,291 2,176 Net income attributable to Parsons Corporation - diluted $ 237,985 $ 163,440 $ 98,840 Denominator for Basic and Diluted EPS: Basic weighted average number of shares outstanding 106,274 104,992 103,758 Dilutive effect of stock-based awards 1,778 1,173 808 Dilutive effect of warrants 494 — — Dilutive effect of convertible senior notes 3,628 8,917 8,917 Diluted weighted average number of shares outstanding 112,174 115,082 113,483 Earnings per share: Basic $ 2.21 $ 1.53 $ 0.93 Diluted $ 2.12 $ 1.42 $ 0.87
Schedule of Repurchase Program	The following table summarizes the repurchase activity under the stock repurchase program. 2024 2023 Total shares repurchased 287,005 233,010 Total shares retired 287,005 233,010 Average price paid per share $ 87.10 $ 47.21

Segments Information (Tables)

Segments Information (Tables)	12 Months Ended
	Dec. 31, 2024
Segment Reporting [Abstract]
Summary of Adjusted EBITDA Business Segment Information	The following tables present segment information provided to the CODM, as of each fiscal year presented, along with a reconciliation of segment adjusted EBITDA attributable to Parsons Corporation to net income attributable to Parsons Corporation for the periods presented (in thousands): Twelve Months Ended December 31, 2024 Federal Critical Total Revenue $ 4,007,114 $ 2,743,462 $ 6,750,576 Direct cost of contracts ( 3,187,829 ) ( 2,156,325 ) ( 5,344,154 ) Selling, general and administrative expenses (a) ( 157,442 ) ( 146,744 ) ( 304,186 ) Equity in earnings (losses) of unconsolidated joint ventures 3,254 ( 26,615 ) ( 23,361 ) Other segment items (b) ( 249,759 ) ( 280,877 ) ( 530,636 ) Adjusted EBITDA attributable to Parsons Corporation $ 415,338 $ 132,901 548,239 Reconciliation: Segment Adjusted EBITDA to Net Income Attributable to Parsons Corporation Adjusted EBITDA attributable to non-controlling interests 56,714 Depreciation and amortization ( 99,251 ) Interest expense, net ( 40,154 ) Income tax expense ( 76,986 ) Equity-based compensation expense ( 61,492 ) Convertible debt repurchase loss ( 18,355 ) Transaction related costs (c) ( 17,138 ) Other (e) ( 912 ) Net income including noncontrolling interests 290,665 Net income attributable to noncontrolling interests ( 55,612 ) Net income attributable to Parsons Corporation $ 235,053 Twelve Months Ended December 31, 2023 Federal Critical Total Revenue $ 3,020,701 $ 2,422,048 $ 5,442,749 Direct cost of contracts ( 2,375,350 ) ( 1,861,385 ) ( 4,236,735 ) Selling, general and administrative expenses (a) ( 129,507 ) ( 129,747 ) ( 259,254 ) Equity in earnings (losses) of unconsolidated joint ventures 4,190 ( 51,941 ) ( 47,751 ) Other segment items (b) ( 230,784 ) ( 251,190 ) ( 481,974 ) Adjusted EBITDA attributable to Parsons Corporation 289,250 127,785 417,035 Reconciliation: Segment Adjusted EBITDA to Net Income Attributable to Parsons Corporation Adjusted EBITDA attributable to non-controlling interests 47,638 Depreciation and amortization ( 119,973 ) Interest expense, net ( 29,306 ) Income tax expense ( 56,138 ) Equity-based compensation expense ( 36,151 ) Transaction related costs (c) ( 12,013 ) Restructuring expense (d) ( 1,244 ) Other (e) ( 1,933 ) Net income including noncontrolling interests 207,915 Net income attributable to noncontrolling interests ( 46,766 ) Net income attributable to Parsons Corporation $ 161,149 Twelve Months Ended December 31, 2022 Federal Critical Total Revenue $ 2,212,987 $ 1,982,285 $ 4,195,272 Direct cost of contracts ( 1,703,297 ) ( 1,545,253 ) ( 3,248,550 ) Selling, general and administrative expenses (a) ( 117,759 ) ( 110,468 ) ( 228,227 ) Equity in earnings of unconsolidated joint ventures 3,677 12,670 16,347 Other segment items (b) ( 196,604 ) ( 215,849 ) ( 412,453 ) Adjusted EBITDA attributable to Parsons Corporation 199,004 123,385 322,389 Reconciliation: Segment Adjusted EBITDA to Net Income Attributable to Parsons Corporation Adjusted EBITDA attributable to non-controlling interests 30,393 Depreciation and amortization ( 120,501 ) Interest expense, net ( 22,219 ) Income tax expense ( 39,657 ) Equity-based compensation expense ( 24,354 ) Transaction related costs (c) ( 16,270 ) Restructuring expense (d) ( 213 ) Other (e) ( 3,003 ) Net income including noncontrolling interests 126,565 Net income attributable to noncontrolling interests ( 29,901 ) Net income attributable to Parsons Corporation $ 96,664 (a) The amount of selling, general and administrative expenses (“SG&A”) is total SG&A excluding allocations. (b) The amount of other segment items is the difference between segment revenue less direct cost of contracts, segment SG&A expenses, equity in earnings (losses) of unconsolidated joint ventures, and Adjusted EBITDA attributable to Parsons Corporation. Other segment items primarily include: i. Corporate and shared segment SG&A (excluding Adjusted EBITDA items) ii. Noncontrolling interests attributable to operating income and other income/expense iii. Bad debt expense iv. Sublease income v. Foreign currency gain/loss, and vi. Certain other income/expense items (c) Reflects costs incurred in connection with acquisitions, and other non-recurring transaction costs, primarily fees paid for professional services and employee retention. (d) Reflects costs associated with and related to our corporate restructuring initiatives. Includes a combination of gain/loss related to sale of fixed assets, software implementation costs, and other individually insignificant items that are non-recurring in nature.
Summary of Revenues and Property and Equipment, Net by Geographic Area	The following table presents revenues and property and equipment, net by geographic area (in thousands): 2024 2023 2022 Revenues: North America $ 5,677,933 $ 4,481,492 $ 3,463,128 Middle East 1,052,509 943,175 710,830 Rest of World 20,134 18,082 21,314 Total revenues $ 6,750,576 $ 5,442,749 $ 4,195,272 Property and equipment, net North America $ 101,044 $ 91,766 $ 91,217 Middle East 10,531 7,191 4,833 Total property and equipment, net $ 111,575 $ 98,957 $ 96,050
Summary of Revenues by Business Lines	The following table presents revenues by business lines (in thousands): 2024 2023 2022 Revenue: Defense & Intelligence $ 1,772,481 $ 1,539,968 $ 1,368,779 Engineered Systems 2,234,633 1,480,733 844,208 Federal Solutions revenues 4,007,114 3,020,701 2,212,987 Infrastructure – North America 1,683,664 1,472,768 1,265,376 Infrastructure – Europe, Middle East and Africa 1,059,798 949,280 716,909 Critical Infrastructure revenues 2,743,462 2,422,048 1,982,285 Total revenues $ 6,750,576 $ 5,442,749 $ 4,195,272

Quarterly Information - Unaud_2

Quarterly Information - Unaudited (Tables)	12 Months Ended
	Dec. 31, 2024
Quarterly Financial Information Disclosure [Abstract]
Schedule of Selected Quarterly Financial Information	The following table presents selected quarterly financial information (in thousands except per share data). Quarter Ended March 31, 2024 December 31, 2024 Federal Solutions revenue $ 909,608 $ 1,003,323 Critical Infrastructure revenue 626,068 730,994 Total revenue 1,535,676 1,734,317 Operating income 101,844 99,812 Convertible debt repurchase loss (1) ( 18,355 ) - Income tax expense (1) ( 13,324 ) ( 18,729 ) Net income attributable to Parsons Corporation (1) 39,750 54,180 Earnings per share: Basic $ 0.37 $ 0.51 Diluted (2) $ 0.37 $ 0.49 1 Presents the revised quarterly financial data resulting from the adoption of Accounting Standards Update (“ASU”) 2024-04 as of January 1, 2024 on a prospective basis. As a result of the adoption of ASU 2024-04 , the Company reversed a loss on extinguishment of debt for the partial repurchase of the Convertible Senior Notes due 2025 and recorded the repurchase transaction as an induced conversion. This change from extinguishment to inducement accounting resulted in the Company (i.) reversing the $ 211.0 million loss and the related $ 49.9 million tax benefit on extinguishment of debt, recorded in Q1 2024, (ii.) recording a $ 18.4 million convertible debt repurchase loss, (iii.) the difference between the extinguishment loss and inducement expense of $ 192.6 million recorded to equity, and (iv.) the related tax benefit of $ 45.6 million recorded to equity. See "Note 2—Summary of Significant Accounting Polices—New Accounting Pronouncements " for a further discussion of the first quarter 2024 extinguishment accounting and subsequent change to inducement accounting. 2 Diluted earnings per share prior to the adoption of ASU 2024-04 did not include certain adjustments as their inclusion would have been antidilutive. Subsequent to the adoption of ASU 2024-04 these adjustments are no longer antidilutive. Dilutive adjustments include if converted interest of $ 2.8 million, 1.5 million shares related to stock based awards and 6.8 million shares related to convertible senior notes. Inclusion of these dilution adjustments resulted in dilutive net income attributable to Parsons Corporation of $ 42.5 million and total diluted shares of 114.4 million for the quarter ended March 31, 2024.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Additional Information (Details)		1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 01, 2024 USD ($)	Feb. 29, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) Customer shares	Dec. 31, 2023 USD ($) Customer shares	Dec. 31, 2022 USD ($) shares	Sep. 30, 2021 USD ($)	Aug. 09, 2021 USD ($)
Significant Accounting Policies [Line Items]
Contributions to ESOP | shares				633,033	915,113	1,188,129
Number of authorized shares of common stock value		$ 100,000,000
Reduction in quarterly cap value on stock repurchased		25,000,000
Stock repurchase value		54,700,000
Reversal of loss on extinguishment of debt	$ 211,000,000		$ 211,000,000
Reversal of tax benefit of loss on extinguishment of debt	49,900,000		49,900,000
Convertible debt repurchase loss	18,400,000		$ 18,355,000	$ 18,355,000	$ 0	$ 0
Increase in shareholders equity relating to reversal of loss on extinguishment of debt and inducement expenses	192,600,000			192,600,000
Adjustments to shareholders equity relating to reversal of tax benefit	$ 45,600,000			$ 45,600,000
Change in accounting principle, accounting standards update, immaterial effect					false
ASU 2024-04
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted				true
Change in accounting principle, accounting standards update, adoption date				Jan. 01, 2024
Change in accounting principle, accounting standards update, immaterial effect				false
Change in accounting principle, accounting standards update, early adoption				true
ASU 2021-08
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adoption date				Jan. 01, 2022
Change in accounting principle, accounting standards update, immaterial effect				true
Change in accounting principle, accounting standards update, early adoption				true
ASU 2023-07
Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted				true
Change in accounting principle, accounting standards update, immaterial effect				true
Concentration of Customer Risk | United States
Significant Accounting Policies [Line Items]
Number of customers representing more than 10% of revenue | Customer				0
Concentration of Credit Risk | United States
Significant Accounting Policies [Line Items]
Number of customers representing more than 10% of accounts receivable | Customer					0
Revenue Benchmark | Concentration of Customer Risk | United States
Significant Accounting Policies [Line Items]
Concentration risk percentage				59%	55%	53%
Number of customers representing more than 20% of revenue | Customer				2
Accounts Receivable | Concentration of Credit Risk | United States
Significant Accounting Policies [Line Items]
Concentration risk percentage				23%	18%
Maximum
Significant Accounting Policies [Line Items]
Number of authorized shares of common stock value		$ 100,000,000		$ 154,700,000			$ 100,000,000	$ 100,000,000
Performance obligations payment terms from date of invoice				120 days
Amortization Period (in years)				16 years
Minimum
Significant Accounting Policies [Line Items]
Performance obligations payment terms from date of invoice				30 days
Amortization Period (in years)				1 year

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details)							3 Months Ended		12 Months Ended
	Nov. 01, 2024 USD ($)	Aug. 16, 2024 USD ($)	Oct. 31, 2023 USD ($)	Aug. 23, 2023 USD ($)	Apr. 13, 2023 USD ($)	May 31, 2022 USD ($)	Dec. 31, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Business Acquisition [Line Items]
Amortization of intangible assets									$ 55,600,000	$ 76,600,000	$ 78,200,000
Revenues							$ 1,734,317,000	$ 1,535,676,000	6,750,576,000	5,442,749,000	4,195,272,000
Goodwill							2,082,680,000		2,082,680,000	1,792,665,000	1,661,850,000
BCC Engineering, LLC
Business Acquisition [Line Items]
Percentage of ownership interest acquired	100%
Cash paid to acquire	$ 232,700,000
Amortization of intangible assets									1,500,000
Revenues									20,300,000
Goodwill	$ 174,532,000
Goodwill deductible for tax purposes							45,800,000		45,800,000
BCC Engineering, LLC | Selling, General and Administrative Expense
Business Acquisition [Line Items]
Acquisition related expenses									4,200,000
BlackSignal Technologies, LLC.
Business Acquisition [Line Items]
Percentage of ownership interest acquired		100%
Cash paid to acquire		$ 203,700,000
Amortization of intangible assets									4,300,000
Revenues									22,700,000
Goodwill		119,663,000
Goodwill deductible for tax purposes		$ 15,700,000
BlackSignal Technologies, LLC. | Selling, General and Administrative Expense
Business Acquisition [Line Items]
Acquisition related expenses									2,500,000
I.S. Engineers, LLC
Business Acquisition [Line Items]
Percentage of ownership interest acquired			100%
Cash paid to acquire			$ 12,200,000
Goodwill			$ 11,900,000
I.S. Engineers, LLC | Selling, General and Administrative Expense
Business Acquisition [Line Items]
Acquisition related expenses										300,000
Sealing Technologies, Inc.
Business Acquisition [Line Items]
Percentage of ownership interest acquired				100%
Cash paid to acquire				$ 176,028,000
Earn out payment due and payable to the selling shareholders, Multiplier				0.5
Estimated fair value of contingent consideration							$ 0		0	2,300,000
Gain on change in fair value of contingent consideration				$ 3,231,000
Borrowed under credit agreement to partially fund the acquisition				175,000,000
Acquisition related expenses				3,300,000
Amortization of intangible assets									12,900,000	7,000,000
Revenues										34,100,000
Goodwill				90,593,000
Sealing Technologies, Inc. | Other Income (Expense), Net
Business Acquisition [Line Items]
Gain on change in fair value of contingent consideration									2,300,000
Sealing Technologies, Inc. | Maximum
Business Acquisition [Line Items]
Additional amount agreed to pay the selling shareholders in the event an earn out revenue target is exceeded				25,000,000
Earn out revenue target, amount				110,000,000
Target amount of earnout revenue				25,000,000
Sealing Technologies, Inc. | Minimum
Business Acquisition [Line Items]
Target amount of earnout revenue				$ 0
IPKeys Power Partners
Business Acquisition [Line Items]
Percentage of ownership interest acquired					100%
Cash paid to acquire					$ 43,000,000
Amortization of intangible assets									1,600,000	1,400,000
Revenues										9,300,000
Goodwill					22,407,000
Goodwill deductible for tax purposes					$ 900,000
IPKeys Power Partners | Selling, General and Administrative Expense
Business Acquisition [Line Items]
Acquisition related expenses										600,000
Xator Corporation
Business Acquisition [Line Items]
Percentage of ownership interest acquired						100%
Cash paid to acquire						$ 387,500,000
Borrowed under credit agreement to partially fund the acquisition						300,000,000
Amortization of intangible assets									$ 16,500,000	$ 18,100,000	11,900,000
Revenues											157,800,000
Goodwill						$ 257,934,000
Xator Corporation | Selling, General and Administrative Expense
Business Acquisition [Line Items]
Acquisition related expenses											$ 7,700,000

Acquisitions - Schedule Of Acqu

Acquisitions - Schedule Of Acquisition Date Fair Value of the Purchase Consideration Transferred (Details) - Sealing Technologies, Inc. $ in Thousands	Aug. 23, 2023 USD ($)
Business Acquisition [Line Items]
Cash paid at closing	$ 176,028
Fair value of contingent consideration to be achieved	3,231
Total purchase price	$ 179,259

Acquisitions - Summary of Estim

Acquisitions - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Purchase Price Allocation (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Nov. 01, 2024	Aug. 16, 2024	Dec. 31, 2023	Aug. 23, 2023	Apr. 13, 2023	Dec. 31, 2022	May 31, 2022
Business Acquisition [Line Items]
Contract assets	$ 741,504			$ 757,515
Goodwill	2,082,680			1,792,665			$ 1,661,850
Investments in and advances to unconsolidated joint ventures	138,759			128,204
Contract liabilities	$ (289,799)			$ (301,107)
BCC Engineering, LLC
Business Acquisition [Line Items]
Cash and cash equivalents		$ 2,839
Accounts receivable		24,142
Contract assets		16,649
Prepaid expenses and other current assets		2,483
Right of use assets, operating leases		9,438
Property and equipment		1,586
Goodwill		174,532
Intangible assets		32,400
Other noncurrent assets		1,743
Accounts payable		(8,668)
Accrued expenses and other current liabilities		(7,236)
Contract liabilities		(4,446)
Short-term lease liabilities, operating leases		(1,977)
Deferred income taxes		(2,203)
Long-term lease liabilities, operating leases		(7,462)
Other long-term liabilities		(1,155)
Net assets acquired		$ 232,665
BlackSignal Technologies, LLC.
Business Acquisition [Line Items]
Cash and cash equivalents			$ 4,917
Accounts receivable			5,171
Contract assets			3,209
Prepaid expenses and other current assets			447
Right of use assets, operating leases			5,370
Property and equipment			997
Goodwill			119,663
Intangible assets			97,600
Other assets			145
Accounts payable			(951)
Accrued expenses and other current liabilities			(4,999)
Short-term lease liabilities, operating leases			(800)
Deferred income taxes			(22,461)
Long-term lease liabilities, operating leases			(4,570)
Net assets acquired			$ 203,738
Sealing Technologies, Inc.
Business Acquisition [Line Items]
Cash and cash equivalents					$ 8,133
Accounts receivable					17,889
Contract assets					2,946
Prepaid expenses and other current assets					1,379
Right of use assets, operating leases					1,836
Property and equipment					2,025
Goodwill					90,593
Deferred tax assets					357
Intangible assets					75,000
Accounts payable					(15,987)
Accrued expenses and other current liabilities					(2,408)
Contract liabilities					(668)
Short-term lease liabilities, operating leases					(418)
Long-term lease liabilities, operating leases					(1,418)
Net assets acquired					$ 179,259
IPKeys Power Partners
Business Acquisition [Line Items]
Cash and cash equivalents						$ 126
Accounts receivable						3,937
Contract assets						834
Prepaid expenses and other current assets						455
Right of use assets, operating leases						1,105
Property and equipment						86
Goodwill						22,407
Intangible assets						23,000
Other noncurrent assets						152
Accounts payable						(541)
Accrued expenses and other current liabilities						(1,768)
Contract liabilities						(1,936)
Short-term lease liabilities, operating leases						(343)
Long-term lease liabilities, operating leases						(762)
Deferred tax liabilities						(3,713)
Net assets acquired						$ 43,039
Xator Corporation
Business Acquisition [Line Items]
Cash and cash equivalents								$ 8,935
Accounts receivable								7,393
Contract assets								24,332
Prepaid expenses and other current assets								3,615
Right of use assets, operating leases								7,517
Property and equipment								1,699
Goodwill								257,934
Investments in and advances to unconsolidated joint ventures								698
Intangible assets								123,500
Other noncurrent assets								9,156
Accounts payable								(6,626)
Accrued expenses and other current liabilities								(31,309)
Contract liabilities								(2,631)
Short-term lease liabilities, operating leases								(2,371)
Long-term lease liabilities, operating leases								(5,146)
Other long-term liabilities								(9,156)
Net assets acquired								$ 387,540

Acquisitions - Schedule of Inta

Acquisitions - Schedule of Intangible Assets Value on Purchase Price (Details) - USD ($) $ in Thousands							12 Months Ended
		Nov. 01, 2024	Aug. 16, 2024	Aug. 23, 2023	Apr. 13, 2023	May 31, 2022	Dec. 31, 2024
Customer Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)							11 years 7 months 6 days
Customer Relationships | BCC Engineering, LLC
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 6,500
Amortization Period (in years)		4 years
Customer Relationships | BlackSignal Technologies, LLC.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 73,900
Amortization Period (in years)			14 years
Customer Relationships | Sealing Technologies, Inc.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount				$ 40,000
Amortization Period (in years)				14 years
Customer Relationships | IPKeys Power Partners
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	[1]				$ 15,900
Amortization Period (in years)	[1]				16 years
Customer Relationships | Xator Corporation
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount						$ 37,000
Amortization Period (in years)						15 years
Backlog
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)							4 years 6 months
Backlog | BCC Engineering, LLC
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 23,400
Amortization Period (in years)		4 years
Backlog | BlackSignal Technologies, LLC.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 11,700
Amortization Period (in years)			3 years
Backlog | Sealing Technologies, Inc.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount				$ 26,000
Amortization Period (in years)				3 years
Backlog | Xator Corporation
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount						$ 81,000
Amortization Period (in years)						6 years
Trade Names
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)							1 year
Trade Names | Xator Corporation
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount						$ 4,000
Amortization Period (in years)						1 year
Developed Technologies
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)							4 years 7 months 6 days
Developed Technologies | BlackSignal Technologies, LLC.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 5,200
Amortization Period (in years)			5 years
Developed Technologies | Sealing Technologies, Inc.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount				$ 8,000
Amortization Period (in years)				3 years
Developed Technologies | IPKeys Power Partners
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount					$ 7,000
Amortization Period (in years)					11 years
Developed Technologies | Xator Corporation
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount						$ 1,000
Amortization Period (in years)						3 years
Noncompete Agreements
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)							3 years
Noncompete Agreements | BCC Engineering, LLC
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 1,700
Amortization Period (in years)		3 years
Noncompete Agreements | BlackSignal Technologies, LLC.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 6,100
Amortization Period (in years)			3 years
Noncompete Agreements | Xator Corporation
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount						$ 500
Amortization Period (in years)						3 years
Other | BCC Engineering, LLC
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount		$ 800
Amortization Period (in years)		1 year
Other | BlackSignal Technologies, LLC.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount			$ 700
Amortization Period (in years)			1 year
Other | Sealing Technologies, Inc.
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount				$ 1,000
Amortization Period (in years)				1 year
Other | IPKeys Power Partners
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount					$ 100
Amortization Period (in years)					1 year
[1] The acquired business is a SaaS commercial business. Backlog for this type of business is included as customer relationships.

Acquisitions - Schedule of Supp

Acquisitions - Schedule of Supplemental Pro Forma Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
BCC Engineering, LLC
Business Acquisition [Line Items]
Pro forma Revenue	$ 6,838,190	$ 5,537,090
Pro forma Net Income including noncontrolling interests	286,948	189,200
BlackSignal Technologies, LLC.
Business Acquisition [Line Items]
Pro forma Revenue	6,782,552	5,481,036
Pro forma Net Income including noncontrolling interests	$ 283,900	185,954
Sealing Technologies, Inc.
Business Acquisition [Line Items]
Pro forma Revenue		5,525,099	$ 4,262,525
Pro forma Net Income including noncontrolling interests		216,157	107,937
IPKeys Power Partners
Business Acquisition [Line Items]
Pro forma Revenue		5,445,604	4,207,967
Pro forma Net Income including noncontrolling interests		$ 209,773	123,257
Xator Corporation
Business Acquisition [Line Items]
Pro forma Revenue			4,302,448	$ 3,949,562
Pro forma Net Income including noncontrolling interests			$ 139,901	$ 91,770

Contracts with Customers - Summ

Contracts with Customers - Summary of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Disaggregation Of Revenue [Line Items]
Revenues	$ 1,734,317	$ 1,535,676	$ 6,750,576	$ 5,442,749	$ 4,195,272
Fixed-Price
Disaggregation Of Revenue [Line Items]
Revenues			2,844,719	1,810,499	1,138,482
Time-and-Materials
Disaggregation Of Revenue [Line Items]
Revenues			1,419,168	1,352,871	1,166,548
Cost-Plus
Disaggregation Of Revenue [Line Items]
Revenues			$ 2,486,689	$ 2,279,379	$ 1,890,242

Contracts with Customers - Su_2

Contracts with Customers - Summary of Contract Assets and Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2024
Revenue from Contract with Customer [Abstract]
Contract assets	$ 757,515	$ 741,504
Contract liabilities	301,107	289,799
Net contract assets (liabilities)	456,408	$ 451,705
Change in contract assets	(16,011)
Change in contract liabilities	(11,308)
Change in contract assets and liabilities	$ (4,703)
Percentage change in contract assets	(2.10%)
Percentage change in contract liabilities	(3.80%)
Percentage change in contract assets and liabilities	(1.00%)

Contracts with Customers - Su_3

Contracts with Customers - Summary of Contract Assets and Contract Liabilities (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Contract retentions	$ 89.8	$ 73.8
Contract retentions, not expected to be paid in next 12 months	35.9
Contract assets, net claims recovery estimates	70.7	$ 109.5
Loss recognized related to claims recoveries	$ 21.6

Contracts with Customers - Addi

Contracts with Customers - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue recognized included contract liability	$ 190,300,000	$ 126,000,000
Impairment of contract assets	0	$ 0
Impact of changes in estimated claims or incentives on revenue	5,000,000
Remaining unsatisfied performance obligations	$ 6,700,000,000
U.S. Federal Government and Agencies
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Receivables from contracts rate	23%	18%
Critical Infrastructure | Direct Costs Write-Down
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Increase (decrease) in direct costs of contracts	$ 6,300,000	$ 8
Critical Infrastructure | Legal Matter
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Increase (decrease) in direct costs of contracts		$ 37,900,000

Contracts with Customers - Su_4

Contracts with Customers - Summary of Changes in Contract Assets and Contract Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Acquired contract assets	$ 19,858	$ 2,715
Acquired contract liabilities	$ 4,446	$ 3,155

Contracts with Customers - Su_5

Contracts with Customers - Summary of Changes in Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue impact, net	$ (55,952)	$ 5,428	$ 0

Contracts with Customers - Su_6

Contracts with Customers - Summary Of Finanial Statement Impact From Revisions In Estimates (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Operating income (loss)	$ 99,812	$ 101,844	$ 428,066	$ 288,358	$ 185,666
Net Income (Loss)	$ 54,180	$ 39,750	$ 235,053	$ 161,149	$ 96,664
Diluted earnings (loss) per share	$ 0.49	$ 0.37	$ 2.12	$ 1.42	$ 0.87
Critical Infrastructure
Segment Reporting Information [Line Items]
Operating income (loss)			$ (62,298)	$ 35,297	$ 0
Net Income (Loss)			$ (47,651)	$ 26,261	$ 0
Diluted earnings (loss) per share			$ (0.42)	$ 0.23	$ 0

Contracts with Customers - Su_7

Contracts with Customers - Summary of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Revenue from Contract with Customer [Abstract]
Billed	$ 712,046	$ 646,375
Unbilled	392,236	273,215
Total accounts receivable, gross	1,104,282	919,590
Allowance for doubtful accounts	(3,886)	(3,952)
Total accounts receivable, net	$ 1,100,396	$ 915,638

Contracts with Customers - Su_8

Contracts with Customers - Summary of Remaining Unsatisfied Performance Obligations Expect to Satisfy (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 6,700,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2025-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 3,877,806
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2026-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,538,981
Revenue, remaining performance obligation, expected timing of satisfaction, period	2 years
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2027-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,317,211
Revenue, remaining performance obligation, expected timing of satisfaction, period
Federal Solution Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2025-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,815,751
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Federal Solution Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2026-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 439,216
Revenue, remaining performance obligation, expected timing of satisfaction, period	2 years
Federal Solution Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2027-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 142,994
Revenue, remaining performance obligation, expected timing of satisfaction, period
Critical Infrastructure | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2025-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 2,062,055
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Critical Infrastructure | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2026-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,099,765
Revenue, remaining performance obligation, expected timing of satisfaction, period	2 years
Critical Infrastructure | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2027-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,174,217
Revenue, remaining performance obligation, expected timing of satisfaction, period

Leases - Additional Information

Leases - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Lessee Lease Description [Line Items]
Lease option to extend	five years
Lease existence of option to extend	true
Lease option to terminate	three years
Lease existence of option to terminate	true
Operating lease not yet commenced expense	$ 0
Selling, General and Administrative Expense
Lessee Lease Description [Line Items]
Rental expense	$ 82,000,000	$ 81,000,000	$ 81,000,000
Minimum
Lessee Lease Description [Line Items]
Lease term of contract	1 year
Maximum
Lessee Lease Description [Line Items]
Lease term of contract	11 years

Leases - Summary of Lease Costs

Leases - Summary of Lease Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Operating lease cost	$ 64,858	$ 67,181
Short-term lease cost	17,114	13,782
Amortization of right-of-use assets	3,549	2,699
Interest on lease liabilities	434	273
Sublease income	(4,289)	(4,718)
Total lease cost	$ 81,666	$ 79,217

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Leases [Abstract]
Operating cash flows for operating leases	$ 67,696	$ 71,432
Operating cash flows for finance leases	434	273
Financing cash flows for finance leases	3,376	2,618
Right-of-use assets obtained in exchange for new operating lease liabilities	36,583	62,856
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 4,220	$ 6,456

Leases - Schedule of Suppleme_2

Leases - Schedule of Supplemental Balance Sheet and Other Information Related to Leases (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Operating Leases:
Right-of-use assets	$ 153,048	$ 159,211
Lease liabilities:
Current	52,725	58,556
Long-term	114,386	117,505
Total operating lease liabilities	167,111	176,061
Finance Leases:
Other noncurrent assets	9,864	7,779
Accrued expenses and other current liabilities	$ 3,645	$ 2,682
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Current liabilities	Current liabilities
Other long-term liabilities	$ 6,441	$ 5,129
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other long-term liabilities	Other long-term liabilities
Weighted Average Remaining Lease Term:
Operating leases	3 years 10 months 24 days	3 years 10 months 24 days
Finance leases	2 years 9 months 18 days	3 years 1 month 6 days
Weighted Average Discount Rate:
Operating leases	4.50%	4.20%
Finance leases	5%	4.60%

Leases - Schedule of Maturity A

Leases - Schedule of Maturity Analysis of Future Undiscounted Cash Flows (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Operating Leases
2025	$ 59,839
2026	42,669
2027	29,744
2028	24,383
2029	18,341
Thereafter	7,682
Total lease payments	182,658
Less: imputed interest	(15,547)
Total present value of lease liabilities	167,111	$ 176,061
Finance Leases
2025	4,217
2026	3,492
2027	2,236
2028	933
2029	92
Thereafter	0
Total lease payments	10,970
Less: imputed interest	(884)
Total present value of lease liabilities	$ 10,086

Employee Stock Purchase and E_3

Employee Stock Purchase and Equity-Based Compensation Plans - Schedule of Share Based Compensation Plans Under Equity Securities Authorized for Issuance (Details)	12 Months Ended
	Dec. 31, 2024 shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Securities to be Issued upon Exercise of Outstanding Options, Warrants and Rights	1,883,018
Number of Securities Remaining Available for Future Issuance under Equity Compensation Plans	9,018,870
Equity Compensation Plans Approved By Security Holders
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Securities Remaining Available for Future Issuance under Equity Compensation Plans	1,367,785
Equity Compensation Plans Not Approved By Security Holders
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Securities to be Issued upon Exercise of Outstanding Options, Warrants and Rights	1,883,018
Number of Securities Remaining Available for Future Issuance under Equity Compensation Plans	7,651,085

Employee Stock Purchase and E_4

Employee Stock Purchase and Equity-Based Compensation Plans - Schedule of Share Based Compensation Plans Under Equity Securities Authorized for Issuance (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2024 shares
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Shares purchased under Employee Stock Purchase Plan	47,860
Number of Securities Remaining Available for Future Issuance under Equity Compensation Plans	9,018,870
Number of Securities to be Issued upon Exercise of Outstanding Options, Warrants and Rights	1,883,018
2020 Employee Stock Purchase Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Securities Remaining Available for Future Issuance under Equity Compensation Plans	1,367,785
2019 Incentive Plan
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Securities Remaining Available for Future Issuance under Equity Compensation Plans	7,651,085
2019 Incentive Plan | RSU and PSU | Common Stock
Share-Based Compensation Arrangement by Share-Based Payment Award [Line Items]
Number of Securities to be Issued upon Exercise of Outstanding Options, Warrants and Rights	1,883,018

Employee Stock Purchase and E_5

Employee Stock Purchase and Equity-Based Compensation Plans - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense, net of tax benefits	$ 52.6	$ 27.5	$ 20
Stock-based compensation expense, tax benefits	8.9	8.6	4.4
Stock-based compensation expense, tax benefit realized related to awards vested	12	$ 4.3	$ 2.7
Compensation cost related to non-vested awards not yet recognized	$ 51.3
Vesting period	3 years
Common stock related to employee statutory income tax withholding, shares retired	272,284	159,281	160,212
Restricted Stock Units (Service and Performance Condition)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of awards outstanding	971,110,000	1,008,133,000	803,877,000
Additional shares were granted and vested	99,280	97,551
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period	3 years
Number of awards outstanding	1,883,018,000	2,093,336,000	1,621,155,000	1,359,243,000
Share issued	778,167	484,988	458,952
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of per-share market value limit for share purchases	5%
Average purchase price	$ 82.66	$ 51.94

Employee Stock Purchase and E_6

Employee Stock Purchase and Equity-Based Compensation Plans - Summary of Stock Issuance Activity (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price paid for shares sold	$ 7,935	$ 6,059	$ 5,377
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price paid for shares sold	$ 7,935	$ 6,059
Number of shares sold	96	117

Employee Stock Purchase and E_7

Employee Stock Purchase and Equity-Based Compensation Plans - Summary of Restricted Stock Unit Activity (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Restricted Stock Units (Service Condition)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Units, Granted	346,483	616,337	666,184
Number of Units, Unvested, Beginning balance	1,085,203	817,278
Number of Units, Unvested, Ending balance	911,908	1,085,203	817,278
Restricted Stock Units (Service and Performance Condition)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Units, Granted	296,513	452,179	402,436
Number of Units, Unvested, Beginning balance	1,008,133	803,877
Number of Units, Unvested, Ending balance	971,110	1,008,133	803,877
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Units, Granted	642,996	1,068,516	1,068,620
Weighted Average Grant-Date Fair Value, Granted	$ 79.71	$ 48.96	$ 37.42
Number of Units, Unvested, Beginning balance	2,093,336	1,621,155	1,359,243
Number of Units, Vested	(697,956)	(372,962)	(497,200)
Number of Units, Forfeited	(155,358)	(223,373)	(309,508)
Number of Units, Unvested, Ending balance	1,883,018	2,093,336	1,621,155
Weighted Average Grant-Date Fair Value, Unvested, Beginning balance	$ 43.11	$ 37.49	$ 36.75
Weighted Average Grant-Date Fair Value, Vested	37.83	37.56	35.86
Weighted Average Grant-Date Fair Value, Forfeited	45.33	39.90	36.28
Weighted Average Grant-Date Fair Value, Unvested, Ending balance	$ 57.35	$ 43.11	$ 37.49

Employee Stock Purchase and E_8

Employee Stock Purchase and Equity-Based Compensation Plans - Summary of Restricted Stock Outstanding (Details) - shares shares in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Restricted Stock Units (Service Condition)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of awards outstanding	911,908	1,085,203	817,278
Restricted Stock Units (Service and Performance Condition)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of awards outstanding	971,110	1,008,133	803,877

Goodwill - Summary of Changes i

Goodwill - Summary of Changes in Carrying Value of Goodwill by Reporting Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Goodwill [Line Items]
Beginning Balance	$ 1,792,665	$ 1,661,850
Acquisitions	294,248	129,599
Foreign Exchange	(4,233)	1,216
Ending Balance	2,082,680	1,792,665
Federal Solutions
Goodwill [Line Items]
Beginning Balance	1,686,901	1,591,563
Acquisitions	119,663	95,338
Foreign Exchange	0	0
Ending Balance	1,806,564	1,686,901
Critical Infrastructure
Goodwill [Line Items]
Beginning Balance	105,764	70,287
Acquisitions	174,585	34,261
Foreign Exchange	(4,233)	1,216
Ending Balance	$ 276,116	$ 105,764

Goodwill - Additional Informati

Goodwill - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill impairments	$ 0	$ 0	$ 0

Intangible Assets - Schedule of

Intangible Assets - Schedule of Gross Amount and Accumulated Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 549,855	$ 463,515
Accumulated Amortization	(199,918)	(187,949)
Net Carrying Amount	349,937	275,566
Backlog
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	142,100	130,000
Accumulated Amortization	(51,322)	(45,964)
Net Carrying Amount	$ 90,778	84,036
Weighted Average Amortization Period (in years)	4 years 6 months
Customer Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 372,930	297,120
Accumulated Amortization	(139,568)	(124,194)
Net Carrying Amount	$ 233,362	172,926
Weighted Average Amortization Period (in years)	11 years 7 months 6 days
Leases
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 0	120
Accumulated Amortization	0	(106)
Net Carrying Amount	$ 0	14
Weighted Average Amortization Period (in years)	0 years
Developed technology
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 23,200	31,600
Accumulated Amortization	(7,458)	(15,823)
Net Carrying Amount	$ 15,742	15,777
Weighted Average Amortization Period (in years)	4 years 7 months 6 days
Trade name
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,500	1,000
Accumulated Amortization	(367)	(417)
Net Carrying Amount	$ 1,133	583
Weighted Average Amortization Period (in years)	1 year
Noncompete Agreements
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 8,300	1,500
Accumulated Amortization	(1,203)	(1,097)
Net Carrying Amount	$ 7,097	403
Weighted Average Amortization Period (in years)	3 years
In Process Research and Development
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,800	1,800
Accumulated Amortization	0	0
Net Carrying Amount	1,800	1,800
Other Intangibles
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	25	375
Accumulated Amortization	0	(348)
Net Carrying Amount	$ 25	$ 27

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Finite Lived Intangible Assets [Line Items]
Amortization expense of intangible assets	$ 55.6	$ 76.6	$ 78.2

Intangible Assets - Schedule _2

Intangible Assets - Schedule of Estimated Amortization Expense (Details) $ in Thousands	Dec. 31, 2024 USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2025	$ 64,871
2026	57,313
2027	50,759
2028	36,871
2029	22,659
Thereafter	115,639
Total	$ 348,112

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 397,907	$ 382,745
Accumulated depreciation	(286,332)	(283,788)
Property and equipment, net	111,575	98,957	$ 96,050
Buildings and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 103,945	102,372
Buildings and Leasehold Improvements | Minimum
Property Plant And Equipment [Line Items]
Useful life (years)	1 year
Buildings and Leasehold Improvements | Maximum
Property Plant And Equipment [Line Items]
Useful life (years)	15 years
Furniture and Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 84,720	84,244
Furniture and Equipment | Minimum
Property Plant And Equipment [Line Items]
Useful life (years)	3 years
Furniture and Equipment | Maximum
Property Plant And Equipment [Line Items]
Useful life (years)	10 years
Computer Systems and Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 172,437	168,926
Computer Systems and Equipment | Minimum
Property Plant And Equipment [Line Items]
Useful life (years)	3 years
Computer Systems and Equipment | Maximum
Property Plant And Equipment [Line Items]
Useful life (years)	10 years
Construction Equipment
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 6,463	6,173
Construction Equipment | Minimum
Property Plant And Equipment [Line Items]
Useful life (years)	5 years
Construction Equipment | Maximum
Property Plant And Equipment [Line Items]
Useful life (years)	7 years
Construction in Progress
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 30,342	$ 21,030

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 37.4	$ 39.1	$ 39

Accrued Expenses and Other Cu_3

Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Payables and Accruals [Abstract]
Salaries and wages	$ 119,122	$ 102,779
Employee benefits	371,435	342,707
Self-insurance liability	17,723	24,193
Project cost accruals	307,200	254,070
Other accrued expenses	78,945	77,674
Total accrued expenses and other current liabilities	$ 894,425	$ 801,423

Debt and Credit Facilities - Sc

Debt and Credit Facilities - Schedule of Debt (Details) - USD ($)	Dec. 31, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Short-Term Debt	$ 463,405,000
Long-term debt	0	$ 0
Long-term debt issuance costs	(15,904,000)	(4,037,000)
Total Long-Term Debt	784,096,000	745,963,000
Total Debt	1,247,501,000	745,963,000
Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
Short-Term Debt	113,405,000	0
Convertible senior notes	0	400,000,000
2022 Delayed Draw Term Loan
Debt Instrument [Line Items]
Short-Term Debt	350,000,000	0
Long-term debt		350,000,000
Convertible Senior Notes due 2029
Debt Instrument [Line Items]
Convertible senior notes	800,000,000	0
Revolving Credit Facility
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 0

Debt and Credit Facilities - Ad

Debt and Credit Facilities - Additional Information (Details)		1 Months Ended				3 Months Ended	6 Months Ended	12 Months Ended
	Jan. 01, 2024 USD ($)	Feb. 29, 2024 USD ($) Days $ / shares	Sep. 30, 2022 USD ($)	Jun. 30, 2021 USD ($) Extension	Aug. 31, 2020 USD ($) d $ / shares shares	Mar. 31, 2024 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2024 USD ($) d Days $ / shares shares	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Nov. 30, 2022 USD ($)
Debt Instrument [Line Items]
Effective tax rate and tax benefit								$ 4,300,000
Letters of credit outstanding amount								328,400,000	$ 320,700,000
Debt instrument, outstanding amount								0	0
Tax effect of unwind existing bond hedge								7,701,000	6,977,000
Convertible debt repurchase loss	$ 18,400,000					$ 18,355,000		18,355,000	0	$ 0
Deferred tax liabilities								11,043,000	9,775,000
Deferred tax assets								133,450,000	$ 140,162,000
Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Tax effect of unwind existing bond hedge								$ 46,200,000
Capped Call Transaction
Debt Instrument [Line Items]
Deferred tax assets		$ 22,300,000
2022 Delayed Draw Term Loan
Debt Instrument [Line Items]
Debt issuance costs incurred										900,000
Interest rate								5.60%	6.60%
Interest expense								$ 23,100,000	$ 22,400,000	3,300,000
Debt instrument, outstanding amount								$ 350,000,000	350,000,000		$ 350,000,000
Debt amount			$ 350,000,000
Debt issuance date			Sep. 30, 2022
Debt instrument, maturity period			3 years
Unused term loan commitments rate			0.175%
Convertible Senior Notes | Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Interest rate						0.25%		0.25%
Effective tax rate and tax benefit						$ 49,900,000
Convertible debt repurchase loss								$ 18,400,000
Acceleration charge of amortization of debt issuance costs								3,200,000
Convertible Senior Notes | ASU 2024-04 | Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Loss on extinguishment of debt						211,000,000
Convertible Senior Notes Due 2025
Debt Instrument [Line Items]
Interest rate					0.25%
Interest expense								$ 3,900,000	3,100,000	3,000,000
Debt amount					$ 400,000,000
Exercise of option by initial purchasers aggregate principal amount					50,000,000
Proceeds from issuance and sale of debt					389,700,000
Transaction fees and other third-party offering expenses					$ 10,300,000
Debt instrument, payment terms								The Convertible Senior Notes accrue interest at a rate of 0.25% per annum, payable semi-annually on February 15 and August 15 of each year beginning on February 15, 2021
Debt instrument, frequency of periodic payment								semi-annually
Maturity Date					Aug. 15, 2025
Convertible note converted each amount								$ 1,000
Convertible notes converted each into shares of common stock | shares								22.2913
Debt Instrument, conversion price | $ / shares								$ 44.86
Threshold trading days | d					20			51
Threshold consecutive trading days | d					30
Conversion percentage of stock price trigger					130%
Number of business day period					5 days
Consecutive trading day period					5 days
Convertible principal amount					$ 1,000
Measurement period, percentage					98%
Percentage of principal amount to redeem convertible senior notes					100%
Percentage of convertible senior notes repurchased at cash					100%
Net carrying value of notes								$ 113,400,000	$ 396,500,000
Convertible Senior Notes Due 2025 | Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Proceeds from issuance and sale of debt						391,800,000
Purchase of convertible senior notes		$ 228,100,000
Bond hedge term								5 years
Number of shares issuable upon conversion | shares					8,900,000
Cost of convertible note hedge transaction					$ 55,000,000
Number of common stock acquired by offsetting sale warrants. | shares								8,900,000
Exercise price of warrants | $ / shares								$ 66.46
Proceeds from issuance of warrants								$ 13,800,000
Purchase of bond hedges and sale of warrants					$ 41,200,000
Deferred tax liabilities								16,200,000
Deferred tax assets								16,500,000
Convertible Senior Notes Due 2025 | Capped Call Transaction
Debt Instrument [Line Items]
Debt Instrument, conversion price | $ / shares		$ 131.7575
Cost of convertible note hedge transaction		$ 88,400,000
Premium of reported sale price percentage		75%
Convertible Notes Converted Sale Price Of Common Stock | $ / shares		$ 75.29
Convertible Senior Notes Due 2025 | ASC 2020-06 | Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Deferred tax liability reversed								13,900,000
Additional deferred tax liability related to capitalized debt issuance costs								400,000
Adjustment to deferred tax asset through retained earnings								900,000
Convertible Senior Notes due 2029
Debt Instrument [Line Items]
Interest rate		2.625%
Interest expense								21,300,000
Debt amount		$ 800,000,000
Exercise of option by initial purchasers aggregate principal amount		100,000,000
Proceeds from issuance and sale of debt		781,100,000
Transaction fees and other third-party offering expenses		$ 18,900,000
Debt instrument, payment terms		The 2029 Convertible Notes accrue interest at a rate of 2.625% per annum, payable semi-annually on March 1 and September 1 of each year beginning on September 1, 2024
Debt instrument, frequency of periodic payment		semi-annually
Maturity Date		Mar. 01, 2029
Convertible note converted each amount								$ 1,000
Convertible notes converted each into shares of common stock | shares								10.6256
Debt Instrument, conversion price | $ / shares								$ 94.11
Threshold trading days | Days		20						51
Threshold consecutive trading days | Days		30
Conversion percentage of stock price trigger		130%
Number of business day period		5 days
Consecutive trading day period		10 days
Convertible principal amount		$ 1,000
Measurement period, percentage		98%
Percentage of principal amount to redeem convertible senior notes		100%
Percentage of convertible senior notes repurchased at cash		100%
Net carrying value of notes								$ 784,300,000
Convertible Senior Notes Due 2025 Note Hedge And Warrants | Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Proceeds from issuance and sale of debt						$ 103,800,000
Purchase of convertible senior notes		$ 56,500,000
Proceeds from partial termination of note hedge and warrants		$ 90,600,000
Minimum | Convertible Senior Notes Due 2025 | Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Debt Instrument, conversion price | $ / shares					$ 44.86
Percentage of bond hedge and warrant transactions increased conversion price					35%
Maximum | 2022 Delayed Draw Term Loan
Debt Instrument [Line Items]
Increase in term loan			$ 150,000,000
Maximum | Convertible Senior Notes Due 2025 | Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Debt Instrument, conversion price | $ / shares					$ 66.46
Percentage of bond hedge and warrant transactions increased conversion price					100%
Base Rate | Minimum | 2022 Delayed Draw Term Loan
Debt Instrument [Line Items]
Margin interest rate			0%
Base Rate | Maximum | 2022 Delayed Draw Term Loan
Debt Instrument [Line Items]
Margin interest rate			0.50%
SOFR Benchmark Rate | Minimum | 2022 Delayed Draw Term Loan
Debt Instrument [Line Items]
Margin interest rate			0.875%
SOFR Benchmark Rate | Maximum | 2022 Delayed Draw Term Loan
Debt Instrument [Line Items]
Margin interest rate			1.50%
Revolving Credit Facility
Debt Instrument [Line Items]
Credit agreement date				Jun. 30, 2021
Revolving credit facility				$ 650,000,000			$ 650,000,000
Debt issuance costs incurred				1,900,000			1,900,000
Revolving credit facility				$ 550,000,000			$ 550,000,000
Credit agreement maturity period				5 years
Credit agreement number of extensions | Extension				2
Interest rate								5.70%	6.70%
Letters of credit outstanding amount								$ 43,000,000	$ 43,800,000
Interest expense								$ 700,000	$ 3,900,000	$ 4,300,000
Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Margin interest rate							0%
Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Margin interest rate							0.625%
Revolving Credit Facility | Euro Currency Rate | Minimum
Debt Instrument [Line Items]
Margin interest rate				1%
Revolving Credit Facility | Euro Currency Rate | Maximum
Debt Instrument [Line Items]
Margin interest rate				1.625%

Other Long-term Liabilities - S

Other Long-term Liabilities - Schedule of Other Long-term Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Other Liabilities Disclosure [Abstract]
Self-insurance liability	$ 58,878	$ 81,795
Reserve for uncertain tax positions	22,985	22,815
Finance lease obligations	$ 6,441	$ 5,129
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Total other long-term liabilities	Total other long-term liabilities
Other long-term liabilities	$ 8,182	$ 10,556
Total other long-term liabilities	$ 96,486	$ 120,295

Income Taxes - Components of In

Income Taxes - Components of Income from Operations Before Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Taxes [Line Items]
Income before income tax expense	$ 367,651	$ 264,053	$ 166,222
United States Earnings
Income Taxes [Line Items]
Income before income tax expense	256,210	179,522	77,110
Foreign Earnings
Income Taxes [Line Items]
Income before income tax expense	$ 111,441	$ 84,531	$ 89,112

Income Taxes - Schedule of Inco

Income Taxes - Schedule of Income Tax Expense (Benefit) Attributable to Income from Continuing Operations (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Current
Federal			$ 37,713	$ 37,699	$ 21,323
State			13,441	13,340	9,946
Foreign			19,731	14,013	9,232
Total current income tax expense			70,885	65,052	40,501
Deferred
Federal			1,397	(5,974)	(2,902)
State			3,941	(590)	(623)
Foreign			763	(2,350)	2,681
Total deferred tax benefit			6,101	(8,914)	(844)
Total income tax expense	$ 18,729	$ 13,324	$ 76,986	$ 56,138	$ 39,657

Income Taxes - Computation of I

Income Taxes - Computation of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Income before income tax expense			$ 367,651	$ 264,053	$ 166,222
Tax at federal statutory tax rate			77,207	55,451	34,907
State taxes, net of federal tax benefit			11,852	9,807	7,530
Change in valuation allowance			11,111	5,773	1,363
Change in uncertain tax positions			3,584	3,530	1,688
Foreign tax rate differential			(6,078)	(6,258)	(1,787)
Tax cost of foreign operations, net of credits			1,842	3,085	777
Foreign-derived intangible income deduction			(14,794)	(4,736)	(76)
Noncontrolling interests			(11,679)	(9,821)	(6,279)
Federal business credits			(2,932)	(2,731)	(1,926)
Executive compensation			7,351	1,636	1,921
Equity compensation			(7,170)	(158)	10
Other, net			6,692	560	1,529
Total income tax expense	$ 18,729	$ 13,324	$ 76,986	$ 56,138	$ 39,657
Tax at federal statutory tax rate			21%	21%	21%
State taxes, net of federal tax benefit			3.20%	3.70%	4.50%
Change in valuation allowance			3%	2.20%	0.80%
Change in uncertain tax positions			1%	1.30%	1%
Foreign tax rate differential			(1.70%)	(2.40%)	(1.10%)
Tax cost of foreign operations, net of credits			0.50%	1.20%	0.50%
Foreign-Derived Intangible Income			(4.00%)	(1.80%)	0%
Noncontrolling interests			(3.20%)	(3.70%)	(3.80%)
Federal business credits			(0.80%)	(1.00%)	(1.20%)
Executive compensation			2%	0.60%	1.20%
Equity compensation			(2.00%)	(0.10%)	0%
Other, net			1.80%	0.20%	0.90%
Total income tax expense			20.90%	21.30%	23.90%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Taxes [Line Items]
Effective income tax rate	20.90%	21.30%	23.90%
U.S. corporate tax rate	21%	21%	21%
Deferred tax assets, valuation allowance	$ 45,318	$ 34,779
Deferred tax assets, increase in valuation allowance	10,500
Net operating loss carryforwards	17,640	8,663
Unrecognized tax benefits that would impact effective tax rate	28,600	25,100
Unrecognized tax benefits, income tax penalties and interest expense	1,000	500	$ 700
Unrecognized tax benefits, income tax penalties and interest accrued	5,600	$ 4,600	$ 4,100
Decrease in uncertain tax positions within twelve months	7,200
U.S. States
Income Taxes [Line Items]
Net operating loss carryforwards	20,300
Net operating loss carryforwards, not subject to expiration	8,000
Foreign
Income Taxes [Line Items]
Net operating loss carryforwards	74,200
Net operating loss carryforwards, not subject to expiration	12,900
Foreign tax credit carryforwards	33,500
Foreign tax credits, valuation allowance	$ 33,500
Foreign tax credits, expiration year	2029
U.S. States and Foreign
Income Taxes [Line Items]
Net operating loss carryforwards, expiration description	expire if not used between 2025 and 2045
U.S. States and Foreign | Minimum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration year	2025
U.S. States and Foreign | Maximum
Income Taxes [Line Items]
Net operating loss carryforwards, expiration year	2045
U.S. Federal
Income Taxes [Line Items]
Net operating loss carryforwards	$ 1,700
Net operating loss carryforwards, not subject to expiration	$ 1,700
Open tax year	2021 2022 2023 2024

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Income Tax Disclosure [Abstract]
Project and non-project reserves	$ 23,184	$ 23,555
Employee compensation and benefits	76,944	69,726
Revenue and cost recognition	46,250	37,616
Insurance accruals	12,424	14,081
Net operating losses	17,640	8,663
Lease liabilities	42,572	44,626
Tax credit carryforwards	35,845	31,727
Other	17,432	3,285
Total deferred tax assets	272,291	233,279
Valuation allowance	(45,318)	(34,779)
Total deferred tax assets	226,973	198,500
Deferred tax liabilities
Intangible assets	(57,361)	(18,783)
Right-of-use assets	(38,605)	(40,131)
Profit remittance tax	(6,842)	(5,822)
Other	(1,758)	(3,378)
Total deferred tax liabilities	(104,566)	(68,114)
Net deferred tax asset	$ 122,407	$ 130,386

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Beginning and Ending Balances of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Tax Uncertainties [Abstract]
Beginning of year	$ 25,497	$ 22,798	$ 21,181
Increases—current year tax positions	1,058	3,220	4,666
Increases—prior year tax positions	7,488	2,458	2,254
Decreases—prior year tax positions	(1,826)	(1,589)	(3,537)
Settlements	(1,334)	(1,026)	(1,447)
Lapse of statute of limitations	(1,345)	(364)	(319)
End of year	$ 29,538	$ 25,497	$ 22,798

Contingencies - Additional Info

Contingencies - Additional Information (Details)		12 Months Ended
	Jul. 01, 2024 USD ($)	Dec. 31, 2024 USD ($) Claim	Sep. 23, 2024 USD ($)
Legal Proceedings [Line Items]
Number of claims outstanding | Claim		0
Alleged Violation of False Claims, Act
Legal Proceedings [Line Items]
Amount paid by relator to acquire vehicles for contractor defendant to perform security services		$ 2,900,000
Alleged Violation of False Claims, Act | Minimum
Legal Proceedings [Line Items]
Amount paid per month to contractor defendant by relator on false claims		1,000,000
Loss contingency sought value, civil penalty for each alleged violation of Act		5,500
Alleged Violation of False Claims, Act | Maximum
Legal Proceedings [Line Items]
Loss contingency sought value, civil penalty for each alleged violation of Act		$ 11,000
Alleged Violation of False Claims, Act | Parsons Transportation Group, Inc. and against Alstom Signaling Operations LLC
Legal Proceedings [Line Items]
Award of damages in the total amount	$ 102,500,000
pre-judgment interest			$ 34,000,000

Retirement and Other Benefit _2

Retirement and Other Benefit Plans - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Shares fully vested, Description	Shares allocated to a participant’s account are fully vested after three years of credited service, or in the event(s) of reaching age 65, death or disability while an active employee of the Company.
Shares fully vested after credited service	3 years
Common stock shares outstanding including ESOP	106,775,350	105,839,978
Company's stock held by ESOP	54,117,903	59,879,857
Contribution to 401 (k) plan	$ 37.7	$ 35.4	$ 30.2
Other Noncurrent Assets
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Defined benefit pension plan, net assets position	1.3	1.4
Direct Costs of Contracts and Selling, General and Administrative Expense
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
ESOP contribution expense	$ 59.8	$ 58.2	$ 54.7

Investments in and Advances t_3

Investments in and Advances to Joint Ventures - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Equity Method Investments [Line Items]
Letters of credit outstanding amount	$ 328.4	$ 320.7
Unconsolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Net distributions from (contributions to) unconsolidated joint ventures	38.8	65.2	$ 20.2
Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Letters of credit outstanding amount	$ 176.7	$ 147.7

Investments in and Advances t_4

Investments in and Advances to Joint Ventures - Summary of Financial Information for Consolidated Joint Ventures (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 2,462,400		$ 2,462,400	$ 2,137,526
Total assets	5,487,962		5,487,962	4,804,061
Current liabilities	1,915,644		1,915,644	1,410,884
Total liabilities	2,953,473		2,953,473	2,427,346
Total joint venture equity	2,416,389		2,416,389	2,287,211
Revenue	1,734,317	$ 1,535,676	6,750,576	5,442,749	$ 4,195,272
Costs			5,344,154	4,236,735	3,248,550
Net income attributable to Parsons Corporation	54,180	$ 39,750	235,053	161,149	96,664
Net income attributable to noncontrolling interests			55,612	46,766	29,901
Consolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Current assets	519,450		519,450	426,633
Noncurrent assets	9,841		9,841	14,295
Total assets	529,291		529,291	440,928
Current liabilities	296,774		296,774	260,286
Noncurrent liabilities	2,203		2,203	5,132
Total liabilities	298,977		298,977	265,418
Total joint venture equity	$ 230,314		230,314	175,510
Revenue			788,702	708,391	483,888
Costs			676,258	613,186	422,559
Net income attributable to Parsons Corporation			112,444	95,205	61,329
Net income attributable to noncontrolling interests			$ 55,612	$ 46,766	$ 29,901

Investments in and Advances t_5

Investments in and Advances to Joint Ventures - Summary of Financial Information for Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 2,462,400		$ 2,462,400	$ 2,137,526
Total assets	5,487,962		5,487,962	4,804,061
Current liabilities	1,915,644		1,915,644	1,410,884
Total liabilities	2,953,473		2,953,473	2,427,346
Total joint venture equity	2,416,389		2,416,389	2,287,211
Investments in and advances to unconsolidated joint ventures	138,759		138,759	128,204
Revenue	1,734,317	$ 1,535,676	6,750,576	5,442,749	$ 4,195,272
Costs			5,344,154	4,236,735	3,248,550
Net income attributable to Parsons Corporation	54,180	$ 39,750	235,053	161,149	96,664
Equity in (losses) earnings of unconsolidated joint ventures			(23,361)	(47,751)	16,347
Unconsolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Current assets	1,477,950		1,477,950	1,607,953
Noncurrent assets	431,476		431,476	483,693
Total assets	1,909,426		1,909,426	2,091,646
Current liabilities	947,072		947,072	1,057,113
Noncurrent liabilities	469,808		469,808	518,647
Total liabilities	1,416,880		1,416,880	1,575,760
Total joint venture equity	492,546		492,546	515,886
Investments in and advances to unconsolidated joint ventures	$ 138,759		138,759	128,204
Revenue			2,118,799	2,313,420	2,406,407
Costs			2,108,768	2,310,114	2,325,472
Net income attributable to Parsons Corporation			10,031	3,306	80,935
Unconsolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Equity in (losses) earnings of unconsolidated joint ventures			$ (23,361)	$ (47,751)	$ 16,347

Investments in and Advances t_6

Investments in and Advances to Joint Ventures - Summary of Financial Statement Impact From Changes In Estimates on an Unconsolidated Joint Ventures (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Schedule of Equity Method Investments [Line Items]
Operating loss	$ 99,812	$ 101,844	$ 428,066	$ 288,358	$ 185,666
Net Income (Loss)	$ 54,180	$ 39,750	$ 235,053	$ 161,149	$ 96,664
Diluted loss per share	$ 0.49	$ 0.37	$ 2.12	$ 1.42	$ 0.87
Critical Infrastructure
Schedule of Equity Method Investments [Line Items]
Operating loss			$ (62,298)	$ 35,297	$ 0
Net Income (Loss)			$ (47,651)	$ 26,261	$ 0
Diluted loss per share			$ (0.42)	$ 0.23	$ 0
Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Net Income (Loss)			$ 10,031	$ 3,306	$ 80,935
Unconsolidated Joint Ventures | Critical Infrastructure
Schedule of Equity Method Investments [Line Items]
Operating loss			(51,715)	(83,398)	(13,817)
Net Income (Loss)			$ (44,682)	$ (61,842)	$ (10,335)
Diluted loss per share			$ (0.4)	$ (0.54)	$ (0.09)

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - Unconsolidated Joint Ventures - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Related Party Transaction [Line Items]
Revenues	$ 182.6	$ 213.8	$ 217.4
Reimbursable cost incurred	$ 143.2	$ 153.7	$ 157.6

Related Party Transactions - Sc

Related Party Transactions - Schedule of Consolidated Balance Sheet Related to Services Provided to Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Related Party Transaction [Line Items]
Accounts receivable, net	$ 1,100,396	$ 915,638
Contract assets	741,504	757,515
Contract liabilities	289,799	301,107
Unconsolidated Joint Ventures
Related Party Transaction [Line Items]
Accounts receivable, net	38,443	38,898
Contract assets	11,540	38,009
Contract liabilities	$ 10,776	$ 15,287

Fair Value - Summary of Financi

Fair Value - Summary of Financial Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	$ 7,851	$ 8,763
Liabilities, fair value disclosure		2,300
Mutual Funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	875	1,840
Fixed Income
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	6,627	6,568
Cash and Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	349	355
Earnout Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities, fair value disclosure		2,300
Level 1
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	1,224	2,195
Liabilities, fair value disclosure		0
Level 1 | Mutual Funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	875	1,840
Level 1 | Fixed Income
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	0	0
Level 1 | Cash and Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	349	355
Level 1 | Earnout Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities, fair value disclosure		0
Level 2
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	6,627	6,568
Liabilities, fair value disclosure		0
Level 2 | Mutual Funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	0	0
Level 2 | Fixed Income
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	6,627	6,568
Level 2 | Cash and Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	0	0
Level 2 | Earnout Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities, fair value disclosure		0
Level 3
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	0	0
Liabilities, fair value disclosure		2,300
Level 3 | Mutual Funds
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	0	0
Level 3 | Fixed Income
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	0	0
Level 3 | Cash and Cash Equivalents
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Assets, fair value disclosure	$ 0	0
Level 3 | Earnout Liability
Fair Value Balance Sheet Grouping Financial Statement Captions [Line Items]
Liabilities, fair value disclosure		$ 2,300

Fair Value - Summary of Carryin

Fair Value - Summary of Carrying Values and Estimated Fair Values Of Financial Instruments (Details) - Level 2 - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023
Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	$ 1,263,405	$ 750,000
Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	1,522,486	918,000
Convertible Senior Notes Due 2025 | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	113,405	400,000
Convertible Senior Notes Due 2025 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	233,206	568,000
Convertible Senior Notes due 2029 | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	800,000	0
Convertible Senior Notes due 2029 | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	939,280	0
Delayed draw term loan | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	350,000	350,000
Delayed draw term loan | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-Term Debt, Fair Value	$ 350,000	$ 350,000

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Details) - USD ($)		1 Months Ended	12 Months Ended
	Aug. 09, 2021	Feb. 29, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Sep. 30, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Authorized shares of common stock value		$ 100,000,000
Reduction in quarterly cap value on stock repurchased		25,000,000
Stock repurchase program commencement date	Aug. 12, 2021
Stock repurchase value		54,700,000
Maximum
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Authorized shares of common stock value	$ 100,000,000	$ 100,000,000	$ 154,700,000			$ 100,000,000
Stock repurchase program, remaining authorized repurchase amount			$ 75,000,000
Equity-based Awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share			4,562	5,423	15,113

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Numerator and Denominator used to Compute Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		12 Months Ended
	Jan. 01, 2024	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Numerator for Basic and Diluted EPS:
Net income attributable to Parsons Corporation		$ 54,180	$ 39,750	$ 235,053	$ 161,149	$ 96,664
Convertible senior notes if-converted method interest adjustment	$ 2,800			2,932	2,291	2,176
Diluted net income attributable to Parsons Corporation			$ 42,500	$ 237,985	$ 163,440	$ 98,840
Denominator for Basic and Diluted EPS:
Basic weighted average number of shares outstanding				106,274	104,992	103,758
Dilutive effect of stock-based awards	1,500			1,778	1,173	808
Dilutive effect of warrants				494	0
Dilutive effect of convertible senior notes	6,800			3,628	8,917	8,917
Diluted weighted average number of shares outstanding			114,400	112,174	115,082	113,483
Earnings per share:
Basic		$ 0.51	$ 0.37	$ 2.21	$ 1.53	$ 0.93
Diluted earnings per share		$ 0.49	$ 0.37	$ 2.12	$ 1.42	$ 0.87

Earnings Per Share - Schedule_2

Earnings Per Share - Schedule of Repurchase Program (Details) - $ / shares	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Earnings Per Share [Abstract]
Total shares repurchased	287,005	233,010
Total shares retired	287,005	233,010
Average price paid per share	$ 87.1	$ 47.21

Segments Information - Addition

Segments Information - Additional Information (Details) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($) Segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment			2
Revenues	$ 1,734,317	$ 1,535,676	$ 6,750,576	$ 5,442,749	$ 4,195,272
Property and equipment, net	111,575		111,575	98,957	96,050
United States
Segment Reporting Information [Line Items]
Revenues			5,200,000	4,100,000	3,200,000
Property and equipment, net	$ 94,000		$ 94,000	$ 83,900	$ 84,400

Segments Information - Summary

Segments Information - Summary of Adjusted EBITDA Business Segment Information (Details) - USD ($) $ in Thousands			3 Months Ended		12 Months Ended
		Jan. 01, 2024	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Adjusted EBITDA attributable to Parsons Corporation
Revenue			$ 1,734,317	$ 1,535,676	$ 6,750,576	$ 5,442,749	$ 4,195,272
Direct cost of contracts					(5,344,154)	(4,236,735)	(3,248,550)
Selling, general and administrative expenses	[1]				(304,186)	(259,254)	(228,227)
Equity in earnings (losses) of unconsolidated joint ventures					(23,361)	(47,751)	16,347
Other segment items	[2]				(530,636)	(481,974)	(412,453)
Adjusted EBITDA attributable to Parsons Corporation					548,239	417,035	322,389
Adjusted EBITDA attributable to noncontrolling interests					56,714	47,638	30,393
Depreciation and amortization					(99,251)	(119,973)	(120,501)
Interest expense, net					(40,154)	(29,306)	(22,219)
Income tax expense			(18,729)	(13,324)	(76,986)	(56,138)	(39,657)
Equity-based compensation expense					(61,492)	(36,151)	(24,354)
Convertible debt repurchase loss		$ (18,400)		(18,355)	(18,355)	0	0
Transaction-related costs	[3]				(17,138)	(12,013)	(16,270)
Restructuring expense	[4]					(1,244)	(213)
Other	[5]				(912)	(1,933)	(3,003)
Net income including noncontrolling interests					290,665	207,915	126,565
Net income attributable to noncontrolling interests					(55,612)	(46,766)	(29,901)
Net income attributable to Parsons Corporation			54,180	39,750	235,053	161,149	96,664
Federal Solution Segment
Adjusted EBITDA attributable to Parsons Corporation
Revenue			1,003,323	909,608	4,007,114	3,020,701	2,212,987
Direct cost of contracts					(3,187,829)	(2,375,350)	(1,703,297)
Selling, general and administrative expenses	[1]				(157,442)	(129,507)	(117,759)
Equity in earnings (losses) of unconsolidated joint ventures					3,254	4,190	3,677
Other segment items	[2]				(249,759)	(230,784)	(196,604)
Adjusted EBITDA attributable to Parsons Corporation					415,338	289,250	199,004
Critical Infrastructure
Adjusted EBITDA attributable to Parsons Corporation
Revenue			$ 730,994	$ 626,068	2,743,462	2,422,048	1,982,285
Direct cost of contracts					(2,156,325)	(1,861,385)	(1,545,253)
Selling, general and administrative expenses	[1]				(146,744)	(129,747)	(110,468)
Equity in earnings (losses) of unconsolidated joint ventures					(26,615)	(51,941)	12,670
Other segment items	[2]				(280,877)	(251,190)	(215,849)
Adjusted EBITDA attributable to Parsons Corporation					132,901	127,785	123,385
Net income attributable to Parsons Corporation					$ (47,651)	$ 26,261	$ 0
[1] The amount of selling, general and administrative expenses (“SG&A”) is total SG&A excluding allocations. The amount of other segment items is the difference between segment revenue less direct cost of contracts, segment SG&A expenses, equity in earnings (losses) of unconsolidated joint ventures, and Adjusted EBITDA attributable to Parsons Corporation. Other segment items primarily include: i. Corporate and shared segment SG&A (excluding Adjusted EBITDA items) ii. Noncontrolling interests attributable to operating income and other income/expense iii. Bad debt expense iv. Sublease income v. Foreign currency gain/loss, and vi. Certain other income/expense items Reflects costs incurred in connection with acquisitions, and other non-recurring transaction costs, primarily fees paid for professional services and employee retention. Reflects costs associated with and related to our corporate restructuring initiatives. Includes a combination of gain/loss related to sale of fixed assets, software implementation costs, and other individually insignificant items that are non-recurring in nature.

Segments Information - Summar_2

Segments Information - Summary of Revenues and Property and Equipment, Net by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 1,734,317	$ 1,535,676	$ 6,750,576	$ 5,442,749	$ 4,195,272
Property and equipment, net	111,575		111,575	98,957	96,050
North America
Segment Reporting Information [Line Items]
Revenues			5,677,933	4,481,492	3,463,128
Property and equipment, net	101,044		101,044	91,766	91,217
Middle East
Segment Reporting Information [Line Items]
Revenues			1,052,509	943,175	710,830
Property and equipment, net	$ 10,531		10,531	7,191	4,833
Rest of World
Segment Reporting Information [Line Items]
Revenues			$ 20,134	$ 18,082	$ 21,314

Segments Information - Summar_3

Segments Information - Summary of Revenues by Business Lines (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Segment Reporting Information [Line Items]
Revenues	$ 1,734,317	$ 1,535,676	$ 6,750,576	$ 5,442,749	$ 4,195,272
Federal Solution Segment
Segment Reporting Information [Line Items]
Revenues	1,003,323	909,608	4,007,114	3,020,701	2,212,987
Federal Solution Segment | Defense And Intelligence
Segment Reporting Information [Line Items]
Revenues			1,772,481	1,539,968	1,368,779
Federal Solution Segment | Engineered Systems
Segment Reporting Information [Line Items]
Revenues			2,234,633	1,480,733	844,208
Critical Infrastructure
Segment Reporting Information [Line Items]
Revenues	$ 730,994	$ 626,068	2,743,462	2,422,048	1,982,285
Critical Infrastructure | Infrastructure - North America
Segment Reporting Information [Line Items]
Revenues			1,683,664	1,472,768	1,265,376
Critical Infrastructure | Infrastructure - Europe, Middle East and Africa
Segment Reporting Information [Line Items]
Revenues			$ 1,059,798	$ 949,280	$ 716,909

Quarterly Information - Unaud_3

Quarterly Information - Unaudited - Schedule of Selected Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		12 Months Ended
	Jan. 01, 2024	Dec. 31, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Selected Quarterly Financial Information [Line items]
Total revenues		$ 1,734,317	$ 1,535,676	$ 6,750,576	$ 5,442,749	$ 4,195,272
Operating Income		99,812	101,844	428,066	288,358	185,666
Convertible debt repurchase loss	$ (18,400)		(18,355)	(18,355)	0	0
Income tax expense		(18,729)	(13,324)	(76,986)	(56,138)	(39,657)
Net income attributable to Parsons Corporation		$ 54,180	$ 39,750	$ 235,053	$ 161,149	$ 96,664
Earnings per share:
Basic		$ 0.51	$ 0.37	$ 2.21	$ 1.53	$ 0.93
Diluted earnings per share		$ 0.49	$ 0.37	$ 2.12	$ 1.42	$ 0.87
Federal Solutions
Selected Quarterly Financial Information [Line items]
Total revenues		$ 1,003,323	$ 909,608	$ 4,007,114	$ 3,020,701	$ 2,212,987
Critical Infrastructure
Selected Quarterly Financial Information [Line items]
Total revenues		$ 730,994	$ 626,068	2,743,462	2,422,048	1,982,285
Operating Income				(62,298)	35,297	0
Net income attributable to Parsons Corporation				$ (47,651)	$ 26,261	$ 0
Earnings per share:
Diluted earnings per share				$ (0.42)	$ 0.23	$ 0

Quarterly Information - Unaud_4

Quarterly Information - Unaudited - Schedule of Selected Quarterly Financial Information (Parenthetical) (Details) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended	12 Months Ended
	Jan. 01, 2024	Mar. 31, 2024	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Quarterly Financial Information Disclosure [Abstract]
Accounting Standards Update [Extensible Enumeration]	Accounting Standards Update 2024-04 [Member]
Reversal of loss on extinguishment of debt	$ 211,000	$ 211,000
Reversal of tax benefit of loss on extinguishment of debt	49,900	49,900
Convertible debt repurchase loss	18,400	18,355	$ 18,355	$ 0	$ 0
Increase in shareholders equity relating to reversal of loss on extinguishment of debt and inducement expenses	192,600		192,600
Adjustments to shareholders equity relating to reversal of tax benefit	45,600		45,600
Convertible senior notes if-converted method interest adjustment	$ 2,800		$ 2,932	$ 2,291	$ 2,176
Dilutive effect of stock-based awards	1,500		1,778	1,173	808
Dilutive effect of convertible senior notes	6,800		3,628	8,917	8,917
Diluted net income attributable to Parsons Corporation		$ 42,500	$ 237,985	$ 163,440	$ 98,840
Diluted shares		114,400	112,174	115,082	113,483

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - TRS Group, Inc. - Subsequent Event $ in Millions	2 Months Ended
	Feb. 19, 2025 USD ($)
Subsequent Event [Line Items]
Percentage of ownership interest acquired	100%
Cash paid to acquire	$ 36

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Allowance for Doubtful Accounts
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	$ 3,952	$ 4,011	$ 3,955
Additions			59
Deductions	(66)	(59)	(3)
Balance at end of period	3,886	3,952	4,011
Valuation Allowance on Deferred Tax Assets
Valuation And Qualifying Accounts Disclosure [Line Items]
Balance at beginning of period	34,779	28,705	27,348
Additions	11,452	8,209	3,656
Deductions	(328)	(2,437)	(2,180)
Other and foreign exchange impact	(585)	302	(119)
Balance at end of period	$ 45,318	$ 34,779	$ 28,705