Parsons (PSN) 10-Q 4 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Jul. 28, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
Trading Symbol	PSN
Entity Registrant Name	Parsons Corporation
Entity Central Index Key	0000275880
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		102,502,780
Entity File Number	001-07782
Entity Tax Identification Number	95-3232481
Entity Address, Address Line One	5875 Trinity Parkway #300
Entity Address, City or Town	Centreville
Entity Address, State or Province	VA
Entity Address, Postal Zip Code	20120
City Area Code	703
Local Phone Number	988-8500
Title of 12(b) Security	Common Stock, $1 par value
Security Exchange Name	NYSE
Document Quarterly Report	true
Document Transition Report	false
Entity Incorporation, State or Country Code	DE
Entity Interactive Data Current	Yes

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents (including $57,563 and $75,220 Cash of consolidated joint ventures)	$ 483,443	$ 483,609
Restricted cash and investments	1,145	3,606
Accounts receivable, net (including $173,640 and $190,643 Accounts receivable of consolidated joint ventures, net)	637,980	698,578
Contract assets (including $25,192 and $23,498 Contract assets of consolidated joint ventures)	568,239	576,568
Prepaid expenses and other current assets (including $6,657 and $3,045 Prepaid expenses and other current assets of consolidated joint ventures)	103,599	80,769
Total current assets	1,794,406	1,843,130
Property and equipment, net (including $2,283 and $2,629 Property and equipment of consolidated joint ventures, net)	110,617	121,027
Right of use assets, operating leases	194,484	210,398
Goodwill	1,263,060	1,261,978
Investments in and advances to unconsolidated joint ventures	86,045	68,975
Intangible assets, net	197,985	245,958
Deferred tax assets	147,146	130,200
Other noncurrent assets	45,554	56,038
Total assets	3,839,297	3,937,704
Current liabilities:
Accounts payable (including $85,425 and $97,810 Accounts payable of consolidated joint ventures)	191,688	225,679
Accrued expenses and other current liabilities (including $70,015 and $68,801 Accrued expenses and other current liabilities of consolidated joint ventures)	582,610	650,753
Contract liabilities (including $35,260 and $33,922 Contract liabilities of consolidated joint ventures)	196,547	201,864
Short-term lease liabilities, operating leases	53,997	54,133
Income taxes payable	2,582	4,980
Short-term debt	50,000	50,000
Total current liabilities	1,077,424	1,187,409
Long-term employee incentives	23,222	21,828
Long-term debt	590,876	539,998
Long-term lease liabilities, operating leases	164,754	182,467
Deferred tax liabilities	12,690	12,285
Other long-term liabilities	119,881	132,300
Total liabilities	1,988,847	2,076,287
Contingencies (Note 12)
Shareholders' equity:
Common stock, $1 par value; authorized 1,000,000,000 shares; 146,751,406 and 146,609,288 shares issued; 30,213,867 and 25,719,350 public shares outstanding; 72,288,913 and 76,641,312 ESOP shares outstanding	146,752	146,609
Treasury stock, 44,248,626 shares at cost	(899,328)	(899,328)
Additional paid-in capital	2,673,965	2,700,925
Accumulated deficit	(102,019)	(120,569)
Accumulated other comprehensive loss	(5,905)	(13,865)
Total Parsons Corporation shareholders' equity	1,813,465	1,813,772
Noncontrolling interests	36,985	47,645
Total shareholders' equity	1,850,450	1,861,417
Total liabilities and shareholders' equity	$ 3,839,297	$ 3,937,704

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Cash and cash equivalents	$ 483,443	$ 483,609
Accounts receivable, net	637,980	698,578
Contract assets	568,239	576,568
Prepaid expenses and other current assets	103,599	80,769
Property and equipment, net	110,617	121,027
Accounts payable	191,688	225,679
Accrued expenses and other current liabilities	582,610	650,753
Contract liabilities	$ 196,547	$ 201,864
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	1,000,000,000	1,000,000,000
Common stock, shares, issued	146,751,406	146,609,288
Common stock, shares, outstanding	30,213,867	25,719,350
Treasury stock, shares	44,248,626	44,248,626
ESOP
Common stock, shares, outstanding	72,288,913	76,641,312
Consolidated Joint Ventures
Cash and cash equivalents	$ 57,563	$ 75,220
Accounts receivable, net	173,640	190,643
Contract assets	25,192	23,498
Prepaid expenses and other current assets	6,657	3,045
Property and equipment, net	2,283	2,629
Accounts payable	85,425	97,810
Accrued expenses and other current liabilities	70,015	68,801
Contract liabilities	$ 35,260	$ 33,922

Consolidated Statements of Inco

Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Revenue	$ 879,356	$ 979,459	$ 1,754,053	$ 1,950,452
Direct cost of contracts	680,328	749,324	1,349,410	1,518,956
Equity in earnings of unconsolidated joint ventures	9,428	3,769	16,958	9,883
Selling, general and administrative expenses	188,238	187,640	375,760	371,414
Operating income	20,218	46,264	45,841	69,965
Interest income	152	196	250	424
Interest expense	(4,910)	(4,159)	(9,451)	(8,181)
Other income (expense), net	405	715	(1,386)	263
Total other income (expense)	(4,353)	(3,248)	(10,587)	(7,494)
Income before income tax expense	15,865	43,016	35,254	62,471
Income tax expense	(3,838)	(11,891)	(9,213)	(16,975)
Net income including noncontrolling interests	12,027	31,125	26,041	45,496
Net income attributable to noncontrolling interests	(5,325)	(7,826)	(10,300)	(9,224)
Net income attributable to Parsons Corporation	$ 6,702	$ 23,299	$ 15,741	$ 36,272
Earnings per share:
Basic	$ 0.07	$ 0.23	$ 0.15	$ 0.36
Diluted	$ 0.06	$ 0.23	$ 0.15	$ 0.36

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income including noncontrolling interests	$ 12,027	$ 31,125	$ 26,041	$ 45,496
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment, net of tax	3,012	3,104	7,926	(5,696)
Pension adjustments, net of tax	19	23	38	(38)
Comprehensive income including noncontrolling interests, net of tax	15,058	34,252	34,005	39,762
Comprehensive income attributable to noncontrolling interests, net of tax	(5,324)	(7,830)	(10,304)	(9,220)
Comprehensive income attributable to Parsons Corporation, net of tax	$ 9,734	$ 26,422	$ 23,701	$ 30,542

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities:
Net income including noncontrolling interests	$ 26,041	$ 45,496
Adjustments to reconcile net income to net cash provided by (used in) operating activities
Depreciation and amortization	69,308	64,490
Amortization of debt issue costs	1,530	369
Loss (gain) on disposal of property and equipment	297	(43)
Provision for doubtful accounts	0	38
Deferred taxes	(4,217)	325
Foreign currency transaction gains and losses	2,395	1,185
Equity in earnings of unconsolidated joint ventures	(16,958)	(9,883)
Return on investments in unconsolidated joint ventures	18,132	15,893
Stock-based compensation	11,361	6,432
Contributions of treasury stock	26,518	29,468
Changes in assets and liabilities, net of acquisitions and newly consolidated joint ventures:
Accounts receivable	58,146	(49,618)
Contract assets	8,360	(70,739)
Prepaid expenses and other assets	(11,153)	(999)
Accounts payable	(34,372)	(6,228)
Accrued expenses and other current liabilities	(97,541)	(21,983)
Contract liabilities	(5,957)	(11,047)
Income taxes	(2,402)	4,048
Other long-term liabilities	(11,025)	(28,648)
Net cash provided by (used in) operating activities	38,463	(31,444)
Cash flows from investing activities:
Capital expenditures	(9,171)	(22,938)
Proceeds from sale of property and equipment	384	943
Payments for acquisitions, net of cash acquired	256	0
Investments in unconsolidated joint ventures	(26,373)	(3,844)
Return of investments in unconsolidated joint ventures	727	17
Proceeds from sales of investments in unconsolidated joint ventures	14,335	0
Net cash used in investing activities	(19,842)	(25,822)
Cash flows from financing activities:
Proceeds from borrowings under credit agreement	0	180,600
Repayments of borrowings under credit agreement	0	(180,600)
Payments for debt costs and credit agreement	(1,826)	0
Contributions by noncontrolling interests	872	223
Distributions to noncontrolling interests	(21,836)	(1,605)
Taxes paid on vested stock	(2,242)	(1,149)
Proceeds from issuance of common stock	2,773	1,684
Net cash used in financing activities	(22,259)	(847)
Effect of exchange rate changes	1,011	(641)
Net decrease in cash, cash equivalents, and restricted cash	(2,627)	(58,754)
Cash, cash equivalents and restricted cash:
Beginning of year	487,215	195,374
End of period	$ 484,588	$ 136,620

Consolidated Statements of Shar

Consolidated Statements of Shareholder's Equity (Unaudited) - USD ($) $ in Thousands	Total	Revision of Prior Period, Accounting Standards Update, Adjustment	Common Stock	Treasury Stock	Additional Paid-in Capital	Additional Paid-in CapitalRevision of Prior Period, Accounting Standards Update, Adjustment	Retained Earnings (Accumulated Deficit)	Retained Earnings (Accumulated Deficit)Revision of Prior Period, Accounting Standards Update, Adjustment	Accumulated Other Comprehensive Income (Loss)	Total Parsons Equity	Total Parsons EquityRevision of Prior Period, Accounting Standards Update, Adjustment	Noncontrolling Interest
Beginning balance at Dec. 31, 2019	$ 1,660,756		$ 146,441	$ (934,240)	$ 2,649,975		$ (218,025)		$ (14,261)	$ 1,629,890		$ 30,866
Beginning balance (ASU 2016-13) at Dec. 31, 2019		$ (1,000)						$ (1,000)			$ (1,000)
Comprehensive income
Net income	45,496						36,272			36,272		9,224
Foreign currency translation gain (loss), net	(5,696)								(5,692)	(5,692)		(4)
Pension adjustments, net	(38)								(38)	(38)
Contributions	223											223
Distributions	(1,605)											(1,605)
Issuance of equity securities, net of retirements	1,684		55		1,629					1,684
Stock-based compensation	6,432				6,432					6,432
Ending Balance at Jun. 30, 2020	1,706,252		146,496	(934,240)	2,658,036		(182,753)		(19,991)	1,667,548		38,704
Beginning balance at Mar. 31, 2020	1,667,379		146,441	(934,240)	2,652,227		(206,052)		(23,114)	1,635,262		32,117
Comprehensive income
Net income	31,125						23,299			23,299		7,826
Foreign currency translation gain (loss), net	3,104								3,100	3,100		4
Pension adjustments, net	23								23	23
Contributions	2											2
Distributions	(1,245)											(1,245)
Issuance of equity securities, net of retirements	1,684		55		1,629					1,684
Stock-based compensation	4,180				4,180					4,180
Ending Balance at Jun. 30, 2020	1,706,252		146,496	(934,240)	2,658,036		(182,753)		(19,991)	1,667,548		38,704
Beginning balance at Dec. 31, 2020	1,861,417		146,609	(899,328)	2,700,925		(120,569)		(13,865)	1,813,772		47,645
Beginning balance (ASU 2020-06) at Dec. 31, 2020		$ (37,220)				$ (40,002)		$ 2,782			$ (37,220)
Comprehensive income
Net income	26,041						15,741			15,741		10,300
Foreign currency translation gain (loss), net	7,926								7,922	7,922		4
Pension adjustments, net	38								38	38
Contributions	872											872
Distributions	(21,836)											(21,836)
Issuance of equity securities, net of retirements	1,851		143		1,681		27			1,851
Stock-based compensation	11,361				11,361					11,361
Ending Balance at Jun. 30, 2021	1,850,450		146,752	(899,328)	2,673,965		(102,019)		(5,905)	1,813,465		36,985
Beginning balance at Mar. 31, 2021	1,840,442		146,654	(899,328)	2,667,130		(108,720)		(8,937)	1,796,799		43,643
Comprehensive income
Net income	12,027						6,702			6,702		5,325
Foreign currency translation gain (loss), net	3,012								3,013	3,013		(1)
Pension adjustments, net	19								19	19
Contributions	865											865
Distributions	(12,847)											(12,847)
Issuance of equity securities, net of retirements	2,777		98		2,680		(1)			2,777
Stock-based compensation	4,155				4,155					4,155
Ending Balance at Jun. 30, 2021	$ 1,850,450		$ 146,752	$ (899,328)	$ 2,673,965		$ (102,019)		$ (5,905)	$ 1,813,465		$ 36,985

Description of Operations

Description of Operations	6 Months Ended
	Jun. 30, 2021
Description Of Operations Disclosure [Abstract]
Description of Operations	1. Description of Operations Organization Parsons Corporation, a Delaware corporation, and its subsidiaries (collectively, the “Company”) is a leading provider of technology-driven solutions in the defense, intelligence and critical infrastructure markets. We provide software and hardware products, technical services and integrated solutions to support our customers’ missions. We have developed significant expertise and differentiated capabilities in key areas of cybersecurity, intelligence, missile defense, C5ISR, space, geospatial, and connected communities. By combining our talented team of professionals and advanced technology, we help solve complex technical challenges to enable a safer, smarter and more interconnected world.

Basis of Presentation and Princ

Basis of Presentation and Principles of Consolidation	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Principles of Consolidation	2 . The accompanying unaudited consolidated financial statements and related notes of the Company have been prepared in accordance with generally accepted accounting principles in the United States of America ("GAAP") and pursuant to the interim period reporting requirements of Form 10-Q. They do not include all of the information and footnotes required by GAAP for complete financial statements and, therefore, should be read in conjunction with our consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. In the opinion of management, the consolidated financial statements reflect all normal recurring adjustments necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented. The results of operations and cash flows for any interim period are not necessarily indicative of results for the full year or for future years. This Quarterly Report on Form 10-Q includes 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 a significant influence, the Company applies the equity method of accounting (see “Note 14 – Use of Estimates The preparation of the consolidated financial statements in accordance with 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; calculation of allowance for doubtful accounts; valuation of deferred income tax assets and uncertain tax positions, among others. Please see “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Critical Accounting Policies and Estimates” and “Note 2—Summary of Significant Accounting Polices” in the notes to our consolidated financial statements included in the Company’s Form 10-K for the year ended December 31, 2020, for a discussion of the significant estimates and assumptions affecting our consolidated financial statements. Estimates of costs to complete contracts 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 statement of income. Employee Stock Purchase Plan During the second quarter of fiscal 2020, initial purchases of the Company’s common Stock were made under the Parsons Employee Stock Purchase Program (“ESPP”). Under the ESPP, eligible employees who elect to participate are granted the right to purchase shares of the common stock of Parsons at a discount that is limited to 5% of the per-share market value on the day shares are sold to employees. Purchases of common stock under the ESPP are included in “proceeds from issuance of common stock” in cash flows from financing activities in the Consolidated Statements of Cash Flows.

New Accounting Pronouncements

New Accounting Pronouncements	6 Months Ended
	Jun. 30, 2021
Accounting Policies [Abstract]
New Accounting Pronouncements	3 . In the first quarter of 2021, the Company early adopted Accounting Standards Update (“ASU”) ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06)”. The update simplifies the accounting for convertible debt instruments and convertible preferred stock by reducing the number of accounting models and limiting the number of embedded conversion features separately recognized from the primary contract. The guidance also includes targeted improvements to the disclosures for convertible instruments and earnings per share. ASU 2020-06 is effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020. The Company adopted ASU 2020-06 in the first quarter of 2021 using the modified retrospective method which resulted in a reduction in non-cash interest expense and reclassification of the equity portion of the Convertible Senior Notes to “Long-term debt” on the consolidated balance sheet. In the first quarter of 2021, the Company adopted ASU No. 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”)”. ASU 2019-12 was issued as a means to reduce the complexity of accounting for income taxes. The guidance is to be applied using a prospective method, excluding amendments related to franchise taxes, which should be applied on either a retrospective basis for all periods presented or a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The adoption of ASU 2019-12 did not have a material impact on the consolidated financial statements. In the first quarter of 2020, the Company adopted ASU 2016-13, “Measurement of Credit Losses on Financial Instruments.” The amendments in ASU 2016-13 replaced the incurred loss impairment methodology in current practice with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to estimate credit losses. The adoption of ASU 2016-13 did not have a material impact on the consolidated financial statements.

Acquisitions

Acquisitions	6 Months Ended
	Jun. 30, 2021
Business Combinations [Abstract]
Acquisitions	4. Braxton Science & Technology Group On November 19, 2020, the Company acquired a 100% ownership interest in Braxton Science & Technology Group (“Braxton”), a privately-owned company, for $309.5 million in cash. Braxton operates at the forefront of satellite operations, ground system automation, flight dynamics, and spacecraft and antenna simulation for the U.S. Department of Defense and Intelligence Community. The acquisition was entirely funded by cash on hand in August 2020, as described in “Note 12—Debt and Credit Facilities”. In connection with this acquisition, the Company recognized “Selling, general and administrative expense” in the consolidated statements of income for the six months ended June 30, 2021, including legal fees, consulting fees, and other miscellaneous direct expenses associated with the acquisition. Braxton allows Parsons to capitalize on the quickly evolving space missions of its national security space customers and address rapid market growth driven by proliferated low earth orbit constellations, small satellite expansion, and space cyber resiliency. 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 $ 7,006 Accounts receivable 18,163 Contract assets 8,350 Prepaid expenses and other current assets 3,036 Property and equipment 5,114 Right of use assets, operating leases 10,788 Goodwill 212,185 Intangible assets 74,950 Accounts payable (7,464 ) Accrued expenses and other current liabilities (9,845 ) Contract liabilities (300 ) Short-term lease liabilities, operating leases (1,915 ) Long-term lease liabilities, operating leases (8,873 ) Deferred tax liabilities (1,694 ) Net assets acquired $ 309,501 Of the total purchase price, the following values were assigned to intangible assets (in thousands, except for years): Gross Carrying Amount Amortization Period (in years) Customer relationships $ 34,100 12 Backlog 38,200 3 Developed technologies 2,000 6 Non-compete agreements 650 3 Amortization expense of The amount of revenue generated by Braxton and included within consolidated revenues is $29.3 million and $60.3 million for the three and six months ended June 30, 2021, respectively. Supplemental Pro Forma Information (Unaudited) Supplemental information of unaudited pro forma operating results assuming the Braxton acquisition had been consummated as of the beginning of fiscal year 2019 (in thousands) is as follows: Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Pro forma Revenue $ 879,356 $ 1,003,369 $ 1,754,053 $ 2,004,706 Pro forma Net Income including noncontrolling interests 12,575 31,141 $ 27,929 $ 45,600

Contracts with Customers

Contracts with Customers	6 Months Ended
	Jun. 30, 2021
Revenue From Contract With Customer [Abstract]
Contracts with Customers	5 . 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): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Fixed-Price $ 233,231 $ 311,368 $ 463,173 $ 619,676 Time-and-Materials 253,365 259,381 493,030 511,820 Cost-Plus 392,760 408,710 797,850 818,956 Total $ 879,356 $ 979,459 $ 1,754,053 $ 1,950,452 See “Note 18 – Segments Information” for the Company’s revenues by business lines. Contract Assets and Contract Liabilities Contract assets and contract liabilities balances at June 30, 2021 and December 31, 2020 were as follows (in thousands): June 30, 2021 December 31, 2020 $ change % change Contract assets $ 568,239 $ 576,568 $ (8,329 ) -1.4 % Contract liabilities 196,547 201,864 (5,317 ) -2.6 % Net contract assets (liabilities) (1) $ 371,692 $ 374,704 $ (3,012 ) -0.8 % (1) Total contract retentions included in net contract assets (liabilities) were $94.7 million During the three months ended June 30, 2021 and June 30, 2020, the Company recognized revenue of $23.5 million and $28.4 million, respectively, and $92.6 million and $122.7 million during the six months ended June 30, 2021 and June 30, 2020, respectively, June 30, 2021 December 31, 2020 Acquired contract assets $ - $ 8,350 Acquired contract liabilities - 300 There was no significant impairment of contract assets recognized during the three and six months ended June 30, 2021 and June 30, 2020. 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: Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue impact, net $ (20,827 ) $ 8,983 $ (20,827 ) $ 8,983 Accounts Receivable, net Accounts receivable, net consisted of the following as of June 30, 2021 and December 31, 2020 (in thousands): 2021 2020 Billed $ 458,686 $ 512,357 Unbilled 183,293 190,222 Total accounts receivable, gross 641,979 702,579 Allowance for doubtful accounts (3,999 ) (4,001 ) Total accounts receivable, net $ 637,980 $ 698,578 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. 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. We have not seen and do not expect there to be a risk of non-payment from either our government agency or commercial customers related to COVID-19 impacts; however, we have experienced payment delays due to administrative limitations from both types of customers. Transaction Price Allocated to the Remaining Unsatisfied Performance Obligations The Company’s remaining unsatisfied performance obligations (“RUPO”) as of June 30, 2021 represent a measure of the total dollar value of work to be performed on contracts awarded and in-progress. The Company had $5.1 billion in RUPO as of June 30, 2021. 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 delivery 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 confirmations 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 June 30, 2021 over the following periods (in thousands): Period RUPO Will Be Satisfied Within One Year Within One to Two Years Thereafter Federal Solutions $ 1,071,149 $ 461,928 $ 355,680 Critical Infrastructure 1,581,878 760,048 861,020 Total $ 2,653,027 $ 1,221,976 $ 1,216,700

Leases

Leases	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Leases	6. 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 9 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 three and six months ended June 30, 2021 and June 30, 2020 are as follows (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Operating lease cost $ 16,050 $ 15,755 $ 32,377 $ 33,026 Short-term lease cost 2,264 4,301 4,330 7,952 Amortization of right-of-use assets 543 251 1,017 505 Interest on lease liabilities 28 22 57 46 Sublease income (793 ) (932 ) (1,569 ) (1,812 ) Total lease cost $ 18,092 $ 19,397 $ 36,212 $ 39,717 Supplemental cash flow information related to leases for the six months ended June 30, 2021 and June 30, 2020 is as follows (in thousands): Six Months Ended June 30, 2021 June 30, 2020 Operating cash flows for operating leases $ 33,035 $ 30,676 Operating cash flows for finance leases 58 46 Financing cash flows from finance leases 1,020 553 Right-of-use assets obtained in exchange for new operating lease liabilities 8,328 17,034 Right-of-use assets obtained in exchange for new finance lease liabilities $ 831 $ - Supplemental balance sheet and other information related to leases as of June 30, 2021 and December 31, 2020 are as follows (in thousands): June 30, 2021 December 31, 2020 Operating Leases: Right-of-use assets $ 194,484 $ 210,398 Lease liabilities: Current $ 53,997 $ 54,133 Long-term 164,754 182,467 Total operating lease liabilities $ 218,751 $ 236,600 Finance Leases: Other noncurrent assets $ 3,414 $ 3,363 Accrued expenses and other current liabilities $ 1,598 $ 1,461 Other long-term liabilities $ 1,618 $ 1,733 Weighted Average Remaining Lease Term: Operating leases 4.7 Years 5 years Finance leases 2.5 years 3 years Weighted Average Discount Rate: Operating leases 3.6 % 3.7 % Finance leases 3.0 % 3.8 % As of June 30, 2021, the Company has no 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 June 30, 2021 is as follows (in thousands): Operating Leases Finance Leases 2021 (remaining) $ 30,351 $ 896 2022 58,082 1,358 2023 50,146 684 2024 39,529 274 2025 28,945 106 Thereafter 30,268 3 Total lease payments 237,321 3,321 Less: imputed interest (18,570 ) (105 ) Total present value of lease liabilities $ 218,751 $ 3,216

Goodwill

Goodwill	6 Months Ended
	Jun. 30, 2021
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	7 . The following table summarizes the changes in the carrying value of goodwill by reporting segment from December 31, 2020 to June 30, 2021 (in thousands): December 31, 2020 Acquisitions Foreign Exchange June 30, 2021 Federal Solutions $ 1,188,882 $ (1,292 ) $ - $ 1,187,590 Critical Infrastructure 73,096 - 2,374 75,470 Total $ 1,261,978 $ (1,292 ) $ 2,374 $ 1,263,060 The ultimate impact from the COVID-19 pandemic is difficult to predict. While many uncertainties exist, we currently anticipate no material change in our financial condition or results of operations. Although the Company does not anticipate a material change to our financial condition or results of operations, the Company performed a qualitative triggering analysis and determined there was no triggering event indicating a potential impairment to the carrying value of its goodwill at June 30, 2021 and concluded there has not been an impairment.

Intangible Assets

Intangible Assets	6 Months Ended
	Jun. 30, 2021
Goodwill And Intangible Assets Disclosure [Abstract]
Intangible Assets	8. The gross amount and accumulated amortization of intangible assets with finite useful lives included in “Intangible assets, net” on the consolidated balance sheets are as follows (in thousands except for years): June 30, 2021 December 31, 2020 Weighted Average Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Amortization Period (in years) Backlog $ 147,455 $ (112,066 ) $ 35,389 $ 145,855 $ (101,038 ) $ 44,817 3 Customer relationships 262,830 (133,908 ) 128,922 264,129 (110,450 ) 153,679 8 Leases 670 (609 ) 61 670 (599 ) 71 5 Developed technology 112,939 (82,793 ) 30,146 112,039 (68,968 ) 43,071 4 Trade name 8,200 (8,167 ) 33 8,200 (7,967 ) 233 1 Non-compete agreements 4,250 (2,688 ) 1,562 4,250 (2,043 ) 2,207 3 In process research and development 1,800 - 1,800 1,800 - 1,800 n/a Other intangibles 275 (203 ) 72 275 (195 ) 80 10 Total intangible assets $ 538,419 $ (340,434 ) $ 197,985 $ 537,218 $ (291,260 ) $ 245,958 The aggregate amortization expense of intangible assets for the three months ended June 30, 2021 and June 30, 2020 was $24.5 million and $22.1 million, respectively, and $49.0 million and $44.8 million for the six months ended June 30, 2021 and June 30, 2020, respectively. Estimated amortization expense for the remainder of the current fiscal year and in each of the next four years and beyond is as follows (in thousands): June 30, 2021 2021 $ 48,806 2022 52,230 2023 38,595 2024 12,273 2025 9,713 Thereafter 34,568 Total $ 196,185

Property and Equipment, Net

Property and Equipment, Net	6 Months Ended
	Jun. 30, 2021
Property Plant And Equipment [Abstract]
Property and Equipment, Net	9 . Property and equipment consisted of the following at June 30, 2021 and December 31, 2020 (in thousands): June 30, 2021 December 31, 2020 Useful life (years) Buildings and leasehold improvements $ 97,167 $ 98,151 1-15 Furniture and equipment 88,403 91,036 3-10 Computer systems and equipment 164,302 160,305 3-10 Construction equipment 8,635 8,920 5-7 Construction in progress 9,032 9,202 367,539 367,614 Accumulated depreciation (256,922 ) (246,587 ) Property and equipment, net $ 110,617 $ 121,027 Depreciation expense for the three months ended June 30, 2021 and June 30, 2020 was $9.5 million and $9.8 million, respectively, and $19.2 million and $19.4 million, respectively, for the six months ended June 30, 2021 and June 30, 2020.

Debt and Credit Facilities

Debt and Credit Facilities	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Debt and Credit Facilities	1 0 . Debt consisted of the following (in thousands): June 30, 2021 December 31, 2020 Short-Term: Senior notes $ 50,000 $ 50,000 Total Short-Term 50,000 50,000 Long-Term: Senior notes 200,000 200,000 Convertible senior notes 400,000 400,000 Debt discount - (51,138 ) Debt issuance costs (9,124 ) (8,864 ) Total long-term 590,876 539,998 Total Debt $ 640,876 $ 589,998 Revolving Credit Facility In June 2021 five-year 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 June 30 , 20 2 1 and December 31, 2020 were % and 1.87 %, respectively. Borrowings under this Credit Agreement are guaranteed by certain Company operating subsidiaries. Letters of credit commitments outstanding under this agreement aggregated to $ 45.0 million and $ 44.9 million at June 3 0 , 20 2 1 and December 3 1 , 20 20 , respectively, which reduced borrowing limits available to the Company. Interest expense related to the C redit A greement was $0.3 million and $ 0.3 million for the three months ended June 30, 2021 and June 30, 2020, respectively, and was $0.5 million and $ 0.7 million for six months ended June 30, 202 1 and June 30, 2020 , respectively . There were no loan amounts outstanding under the Credit Agreement on June 3 0 , 202 1 . Private Placement On July 1, 2014, the Company finalized a private placement whereby the Company raised an aggregate amount of $250.0 million in debt as follows (in thousands): Tranche Debt Amount Maturity Date Interest Rates Senior Note, Series A $ 50,000 July 15, 2021 4.44 % Senior Note, Series B 100,000 July 15, 2024 4.98 % Senior Note, Series C 60,000 July 15, 2026 5.13 % Senior Note, Series D 40,000 July 15, 2029 5.38 % The Company incurred $1.1 million of debt issuance costs in connection with the private placement. On August 10, 2018, the Company finalized an amended and restated intercreditor agreement related to this private placement to more closely align certain covenants and definitions with the terms under the 2017 amended and restated Credit Agreement and incurred $0.5 million of additional issuance costs. These costs are presented as a direct deduction from the debt on the face of the consolidated balance sheets. Interest expense related to the Senior Notes for both the three and six months ended June 30, 2021 and June 30, 2020 was $3.1 million 6.2 million The Credit Agreement and private placement 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 June 30, 2021 and December 31, 2020. 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 $219.2 million and $193.1 million at June 30, 2021 and December 31, 2020, respectively. Using a discounted cash flow technique that incorporates a market interest yield curve with adjustments for duration, optionality, and risk profile, the Company estimated the fair value (Level 2) of its Senior Notes at June 30, 2021 approximates $273.9 million. See “Note 16 – Fair Value of Financial Instruments” for the definition of Level 2 of the fair value hierarchy. Convertible Senior Notes 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 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. Under existing GAAP at the time of issuance during 2020, convertible debt instruments that may be settled in cash on conversion were required to be separated into liability and equity components in a manner that reflects the issuer’s non-convertible debt borrowing rate. The carrying amount of the liability component is based on the fair value of a similar instrument that does not contain an equity conversion option. The carrying amount allocated to the equity component, which is recognized as a debt discount, represents the difference between the proceeds from the issuance of the notes and the fair value of the liability component of the notes. Based on this debt to equity ratio, debt issuance costs are then allocated to the liability and equity components in a similar manner. Accordingly, at issuance the Company allocated $336.1 million to the debt liability and $53.6 million to additional paid-in capital. The difference between the principal amount of the Convertible Senior Notes and the liability component, inclusive of issuance costs, represents the debt discount, which the Company amortized to interest expense over the term of the Convertible Senior Notes using an effective interest rate of 3.25 %. During the year ended December 31, 2020, the Company recognized interest expense of $ 4.4 million. As of December 31, 202 0 , the net carrying value of the Notes was $ million. In the first quarter of 2021, the Company early adopted ASU 2020-06, “Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Equity’s Own Equity (Subtopic 815-40)”. The Company used the modified retrospective method which resulted in a reduction in non-cash interest expense and reclassification of equity component of the convertible senior notes of $55.0 million and equity component of the debt issuance costs of $1.4 million to liabilities on the consolidated balance sheet. The Company also adjusted the carrying amount of the convertible senior notes to what it would have been if the Company had applied ASU 2020-06 from the inception of the Notes and recorded the offset of the carrying amount adjustment of $3.7 million in retained earnings on January 1, 2021. During the three and six months ended June 30, 2021, the Company recognized interest expense of $0.7 million and $1.5 million, respectively. As of June 30, 2021, the carrying value of the Notes was $400.0 million. Convertible Note Hedge and Warrant Transactions 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 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 ASU2020-06, 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.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	11. On January 5, 2021, the Treasury Department and Internal Revenue Service issued final regulations which provide guidance on applying the limitations on the deductibility of business interest expense under IRC Section 163(j). On January 6, 2021, the government published final regulations under IRC Section 451. The final regulations include guidance related to (1) timing of income inclusion for taxpayers with an applicable financial statement using an accrual method of accounting under IRC Section 451(b), and (2) advance payments for goods, services, and certain other items under IRC Section 451(c). The Company is currently assessing the impact of the new regulations but does not expect any material impact to its consolidated financial statements. The Company’s effective tax rate was 24.2% and 27.6% for the three months ended June 30, 2021 and 2020, respectively. The change in the effective tax rate was due primarily to an increase in untaxed income attributable to noncontrolling interests and a change in jurisdictional earnings. The Company’s effective tax rate for the six months ended June 30, 2021 and June 30, 2020 was 26.1% and 27.2%. The change in effective tax rate was due primarily to an increase in untaxed income attributed to noncontrolling interests and a change in jurisdictional earnings and partially offset by an increase of foreign tax losses which will not provide any tax benefit and a settlement of a state tax audit. The difference between the effective tax rate and the statutory U.S. Federal income tax rate of 21.0% for the three and six months ended June 30, 2021 primarily relates to state income taxes and a recorded valuation allowance on foreign tax credits, partially offset by benefits related to untaxed income attributable to noncontrolling interests and federal research tax credits. As of June 30, 2021, the Company’s deferred tax assets were subject to a valuation allowance of $31.3 million primarily related to foreign net operating loss carryforwards, foreign tax credit carryforwards, and capital losses that the Company has determined are not more-likely-than-not to be realized. The factors used to assess the likelihood of realization include: the past performance of the entities, forecasts of future taxable income, future reversals of existing taxable temporary differences, and available tax planning strategies that could be implemented to realize the deferred tax assets. The ability or failure to achieve the forecasted taxable income in these entities could affect the ultimate realization of deferred tax assets. As of June 30, 2021 and December 31, 2020, the liability for income taxes associated with uncertain tax positions was $18.0 million and $16.4 million, respectively. It is reasonably possible that the Company may realize a decrease in our uncertain tax positions of approximately $0.2 million during the next 12 months as a result of 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 materially different, both favorably and unfavorably. It is reasonably possible that certain 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	6 Months Ended
	Jun. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Contingencies	1 2 . 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. 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. On or about March 1, 2017, the Peninsula Corridor Joint Powers Board, or the JPB, filed a lawsuit against Parsons Transportation Group, Inc., or PTG, in the Superior Court of California, County of San Mateo, in connection with a positive train control project on which PTG was engaged prior to termination of its contract by the JPB. PTG had previously filed a lawsuit against the JPB for breach of contract and wrongful termination. The JPB seeks damages in excess of $100.0 million, which the Company is currently disputing. In addition to filing a complaint for breach of contract and wrongful termination, the Company has denied the allegations raised by the JPB and, accordingly, filed affirmative defenses. The Company is currently defending against the JPB’s claims and the parties are still engaged in discovery. The Company also has a professional liability insurance policy to the extent the JPB proves any errors or omissions occurred. At this time, the Company is unable to determine the probability of the outcome of the litigation or determine a potential range of loss, if any. The Company has also filed a third-party claim against a subcontractor for indemnification in connection with this matter. 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 United States government did not intervene in this matter as it is allowed to do so under the statute. The Company filed a motion to dismiss the lawsuit on the grounds that the Relator did not meet the applicable statute of limitations. The District Court granted the motion to dismiss. The Relator’s attorney appealed the decision to the United States Court of Appeals of the Eleventh Circuit, which ultimately ruled in favor of the Relator, and the Company petitioned the United States Supreme Court to review the decision. The Supreme Court reviewed the decision and accepted the position of the R elator. The case was thus remanded to the United States District Court for the Northern District of Alabama. The defendants, including Parsons, will file appropriate pleadings opposing the allegations. At this time , the Company is unable to determine the probability of the outcome of the litigation or determine a potential range of loss, if any . 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 Cost Accounting Standards (“CAS”). If the DCAA determines we have not accounted for such costs in accordance with the CAS, 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 2013 have been closed, and years thereafter remain open. 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 Benefit Plan

Retirement Benefit Plan	6 Months Ended
	Jun. 30, 2021
Compensation And Retirement Disclosure [Abstract]
Retirement Benefit Plan	1 3 . The Company’s principal retirement benefit plan is the Parsons Employee Stock Ownership Plan (“ESOP”), a stock bonus plan, established in 1975 to cover eligible employees of the Company and certain affiliated companies. Contributions of treasury stock to the 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 June 30, 2021 and December 31, 2020, total shares of the Company’s common stock outstanding were 102,502,780 and 102,360,662, respectively, of which 72,288,913 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 $13.4 million and $14.6 million for the three months ended June 30, 2021 and June 30, 2020, respectively, and $26.5 million and $29.5 million for the six months ended June 30, 2021 and June 30, 2020, respectively.

Investments in and Advances to

Investments in and Advances to Joint Ventures	6 Months Ended
	Jun. 30, 2021
Equity Method Investments And Joint Ventures [Abstract]
Investments in and Advances to Joint Ventures	1 4 . 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 Variable Interest Entity (“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 10 – Debt and Credit Facilities” that relate to project ventures are $67.5 million 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 (in thousands): June 30, 2021 December 31, 2020 Current assets $ 263,051 $ 292,407 Noncurrent assets 2,641 2,990 Total assets 265,692 295,397 Current liabilities 191,223 201,270 Total liabilities 191,223 201,270 Total joint venture equity $ 74,469 $ 94,127 Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue $ 98,245 $ 117,889 $ 194,869 $ 218,167 Costs 87,097 101,935 173,403 199,085 Net income $ 11,148 $ 15,954 $ 21,466 $ 19,082 Net income attributable to noncontrolling interests $ 5,325 $ 7,826 $ 10,300 $ 9,224 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 joint ventures 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 (in thousands): June 30, 2021 December 31, 2020 Current assets $ 1,042,978 $ 774,646 Noncurrent assets 614,916 585,802 Total assets 1,657,894 1,360,448 Current liabilities 805,616 703,287 Noncurrent liabilities 565,249 517,697 Total liabilities 1,370,865 1,220,984 Total joint venture equity $ 287,029 $ 139,464 Investments in and advances to unconsolidated joint ventures $ 86,045 $ 68,975 Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue $ 736,284 $ 238,188 $ 972,801 $ 691,447 Costs 696,198 223,686 907,045 650,691 Net income $ 40,086 $ 14,502 $ 65,756 $ 40,756 Equity in earnings of unconsolidated joint ventures $ 9,428 $ 3,769 $ 16,958 $ 9,883 The Company received net distributions from and sale proceeds for its unconsolidated joint ventures for the three months ended June 30, 2021 and June 30, 2020 of $1.5 million and $5.6 million, respectively, and $6.8 million and $12.1 million for the six months ended June 30, 2021 and June 30, 2020, respectively. For the three and six months ended June 30, 2021, the Company recorded write-downs of $1.6 million and $5.1 million, respectively, on an unconsolidated joint venture in the Critical Infrastructure segment as a result of changes in estimates made by the managing partner. The write-downs decreased operating and net income by $1.6 million and $1.2 million, respectively for the three months ended June 2021. Operating and net income were decreased by $5.1 million and $3.8 million, respectively, for the six months ended June 30, 2021. The write-downs decreased diluted earnings per share by $0.01 and $0.03 for the three and six months ended June 30, 2021.

Related Party Transactions

Related Party Transactions	6 Months Ended
	Jun. 30, 2021
Related Party Transactions [Abstract]
Related Party Transactions	15. The Company often provides services to unconsolidated joint ventures and revenues include amounts related to recovering costs for these services. Revenues related to services the Company provided to unconsolidated joint ventures for the three months ended June 30, 2021 and June 30, 2020 were $40.5 million and $42.4 million, respectively, and for the six months ended June 30, 2021 and June 30, 2020 were $82.4 million and $82.8 million, respectively. For the three months ended June 30, 2021 and June 30, 2020, the Company incurred $30.6 million and $34.6 million, respectively, and for the six months ended June 30, 2021 and June 30, 2020, $61.9 million and $66.1 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): June 30, 2021 December 31, 2020 Accounts receivable $ 30,897 $ 37,544 Contract assets 9,161 8,889 Contract liabilities 7,887 5,720

Fair Value of Financial Instrum

Fair Value of Financial Instruments	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	1 6 . 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 June 30, 2021 and December 31, 2020, 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 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. Refer to Notes to Consolidated Financial Statements included in the Company’s Form 10-K for the year ended December 31, 2020 for a more complete discussion of the various items within the consolidated financial statements measured at fair value and the methods used to determine fair value.

Earnings Per Share

Earnings Per Share	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Earnings Per Share	1 7 . The following tables reconcile the denominator and numerator used to compute basic earnings per share (“EPS”) to the denominator and numerator used to compute diluted EPS for the three and six months ended June 30, 2021 and June 30, 2020. Basic EPS is computed using the weighted average number of shares outstanding during the period and income available to shareholders. Diluted EPS is computed similar to basic EPS, except the income available to shareholders is adjusted to add back interest expense, after tax, related to the Convertible Senior Note, and the weighted average number of shares outstanding is adjusted to reflect the dilutive effects of stock-based awards and shares underlying the Convertible Senior Note. Dilutive potential common shares include shares the Company could be obligated to issue from its Convertible Senior Notes and warrants (see Note 10 for further discussion) and stock-based awards. Shares to be provided to the Company from its bond hedge purchased concurrently with the issuance of Convertible Senior Notes are anti-dilutive and are not included in its diluted shares. Anti-dilutive stock-based awards excluded from the calculation of earnings per share for the three months ended June 30, 2021 and June 30, 2020 were 9,271 and 4,939, respectively, and for the six months ended June 30, 2021 and June 30, 2020 were 1,644 and 4,066, respectively. The weighted average number of shares used to compute basic and diluted EPS were: Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Basic weighted average number of shares outstanding 102,509,245 100,694,938 102,456,219 100,682,315 Stock-based awards 744,322 290,649 636,162 266,369 Convertible senior notes 8,916,530 - 8,916,530 - Diluted weighted average number of shares outstanding 112,170,097 100,985,587 112,008,911 100,948,684 The net income available to shareholders to compute basic and diluted EPS were (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Net income attributable to Parsons Corporation 6,702 23,299 15,741 36,272 Convertible senior notes if-converted method interest adjustment 531 - 1,059 - Diluted net income attributable to Parsons Corporation 7,233 23,299 16,800 36,272

Segment Information

Segment Information	6 Months Ended
	Jun. 30, 2021
Segment Reporting [Abstract]
Segment Information	18. 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 cybersecurity, 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 Chairman and 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 and segment Adjusted EBITDA attributable to Parsons Corporation. The following table summarizes business segment revenue for the periods presented (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Federal Solutions revenue $ 442,675 $ 482,210 $ 894,744 $ 959,781 Critical Infrastructure revenue 436,681 497,249 859,309 990,671 Total revenue $ 879,356 $ 979,459 $ 1,754,053 $ 1,950,452 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, equity-based compensation, 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. The following table reconciles business segment Adjusted EBITDA attributable to Parsons Corporation to Net Income attributable to Parsons Corporation for the periods presented (in thousands): Three Months Ended Six Months Ended Adjusted EBITDA attributable to Parsons Corporation June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Federal Solutions $ 32,500 $ 47,700 $ 64,482 $ 79,317 Critical Infrastructure 27,817 35,519 59,474 62,876 Adjusted EBITDA attributable to Parsons Corporation 60,317 83,219 123,956 142,193 Adjusted EBITDA attributable to noncontrolling interests 5,410 7,942 10,470 9,464 Depreciation and amortization (34,635 ) (32,081 ) (69,308 ) (64,490 ) Interest expense, net (4,758 ) (3,963 ) (9,201 ) (7,757 ) Income tax expense (3,838 ) (11,891 ) (9,213 ) (16,975 ) Equity-based compensation expense (4,921 ) (12,854 ) (11,901 ) (5,133 ) Transaction-related costs (a) (4,086 ) 2,485 (6,732 ) (9,526 ) Restructuring expense (b) (73 ) (1,143 ) (150 ) (1,110 ) Other (c) (1,389 ) (589 ) (1,880 ) (1,170 ) Net income including noncontrolling interests 12,027 31,125 26,041 45,496 Net income attributable to noncontrolling interests 5,325 7,826 10,300 9,224 Net income attributable to Parsons Corporation $ 6,702 $ 23,299 $ 15,741 $ 36,272 (a) Reflects costs incurred in connection with acquisitions and other non-recurring transaction costs, primarily fees paid for professional services and employee retention. (b) Reflects costs associated with corporate restructuring initiatives. (c) 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 tables present revenues and property and equipment, net by geographic area (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue North America $ 725,047 $ 800,044 $ 1,441,393 $ 1,597,990 Middle East 147,675 174,689 301,318 343,548 Rest of World 6,634 4,726 11,342 8,914 Total Revenue $ 879,356 $ 979,459 $ 1,754,053 $ 1,950,452 The geographic location of revenue is determined by the location of the customer. June 30, 2021 December 31, 2020 Property and Equipment, Net North America $ 106,737 $ 116,460 Middle East 3,880 4,567 Total Property and Equipment, Net $ 110,617 $ 121,027 North America includes revenue in the United States for the three months ended June 30, 2021 and June 30, 2020 of $656.2 million and $737.4 million, respectively and for the six months ended June 30, 2021 and June 30, 2020 of $1.3 billion and $1.5 billion, respectively. The following table presents revenues by business units (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue Cyber & Intelligence $ 85,282 $ 102,993 $ 168,610 $ 201,875 Space & Geospatial Solutions 77,614 57,967 160,673 109,255 Missile Defense & C5ISR 145,493 154,767 290,208 309,336 Engineered Systems 134,286 166,483 275,253 339,315 Federal Solutions revenues 442,675 482,210 894,744 959,781 Connected Communities 81,321 98,359 171,204 200,260 Mobility Solutions 355,360 398,890 688,105 790,411 Critical Infrastructure revenues 436,681 497,249 859,309 990,671 Total Revenue $ 879,356 $ 979,459 $ 1,754,053 $ 1,950,452

Subsequent Events

Subsequent Events	6 Months Ended
	Jun. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	19. On July 6, 2021, the Company completed its acquisition of BlackHorse Solutions, Inc. BlackHorse Solutions, Inc. expands Parsons’ capabilities and products in next-generation military, intelligence, and space operations, specifically in cyber electronic warfare, and information dominance. The purchase price of $203.0 million was paid in cash. We are in the process of finalizing the accounting for this transaction and expect to complete our preliminary allocation of the purchase price to the assets acquired and liabilities assumed by the end of the third quarter of 2021. On July 30, 2021, the Company completed its acquisition of Echo Ridge LLC. Echo Ridge adds position, navigation, and timing devices; modeling, simulation, test, and measurement tools; and deployable software defined radio products and signal processing services to Parsons’ space portfolio. The purchase price of approximately $9.0 million was paid in cash. We are in the process of finalizing the accounting for this transaction and expect to complete our preliminary allocation of the purchase price to the assets acquired and liabilities assumed by the end of the third quarter of 2021.

Basis of Presentation and Pri_2

Basis of Presentation and Principles of Consolidation (Policies)	6 Months Ended
	Jun. 30, 2021
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Principles of Consolidation	The accompanying unaudited consolidated financial statements and related notes of the Company have been prepared in accordance with generally accepted accounting principles in the United States of America ("GAAP") and pursuant to the interim period reporting requirements of Form 10-Q. They do not include all of the information and footnotes required by GAAP for complete financial statements and, therefore, should be read in conjunction with our consolidated financial statements and the notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2020. In the opinion of management, the consolidated financial statements reflect all normal recurring adjustments necessary for a fair statement of the financial position, results of operations and cash flows for the interim periods presented. The results of operations and cash flows for any interim period are not necessarily indicative of results for the full year or for future years. This Quarterly Report on Form 10-Q includes 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 a significant influence, the Company applies the equity method of accounting (see “Note 14 –
Use of Estimates	Use of Estimates The preparation of the consolidated financial statements in accordance with 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; calculation of allowance for doubtful accounts; valuation of deferred income tax assets and uncertain tax positions, among others. Please see “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Critical Accounting Policies and Estimates” and “Note 2—Summary of Significant Accounting Polices” in the notes to our consolidated financial statements included in the Company’s Form 10-K for the year ended December 31, 2020, for a discussion of the significant estimates and assumptions affecting our consolidated financial statements. Estimates of costs to complete contracts 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 statement of income.
Employee Stock Purchase Plan	Employee Stock Purchase Plan During the second quarter of fiscal 2020, initial purchases of the Company’s common Stock were made under the Parsons Employee Stock Purchase Program (“ESPP”). Under the ESPP, eligible employees who elect to participate are granted the right to purchase shares of the common stock of Parsons at a discount that is limited to 5% of the per-share market value on the day shares are sold to employees. Purchases of common stock under the ESPP are included in “proceeds from issuance of common stock” in cash flows from financing activities in the Consolidated Statements of Cash Flows.
New Accounting Pronouncements	In the first quarter of 2021, the Company early adopted Accounting Standards Update (“ASU”) ASU 2020-06, Debt – Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging – Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2020-06)”. The update simplifies the accounting for convertible debt instruments and convertible preferred stock by reducing the number of accounting models and limiting the number of embedded conversion features separately recognized from the primary contract. The guidance also includes targeted improvements to the disclosures for convertible instruments and earnings per share. ASU 2020-06 is effective for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020. The Company adopted ASU 2020-06 in the first quarter of 2021 using the modified retrospective method which resulted in a reduction in non-cash interest expense and reclassification of the equity portion of the Convertible Senior Notes to “Long-term debt” on the consolidated balance sheet. In the first quarter of 2021, the Company adopted ASU No. 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes (“ASU 2019-12”)”. ASU 2019-12 was issued as a means to reduce the complexity of accounting for income taxes. The guidance is to be applied using a prospective method, excluding amendments related to franchise taxes, which should be applied on either a retrospective basis for all periods presented or a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The adoption of ASU 2019-12 did not have a material impact on the consolidated financial statements. In the first quarter of 2020, the Company adopted ASU 2016-13, “Measurement of Credit Losses on Financial Instruments.” The amendments in ASU 2016-13 replaced the incurred loss impairment methodology in current practice with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to estimate credit losses. The adoption of ASU 2016-13 did not have a material impact on the consolidated financial statements.
Leases	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 9 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.

Acquisitions (Tables)

Acquisitions (Tables) - Braxton Science & Technology Group	6 Months Ended
	Jun. 30, 2021
Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Preliminary 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 $ 7,006 Accounts receivable 18,163 Contract assets 8,350 Prepaid expenses and other current assets 3,036 Property and equipment 5,114 Right of use assets, operating leases 10,788 Goodwill 212,185 Intangible assets 74,950 Accounts payable (7,464 ) Accrued expenses and other current liabilities (9,845 ) Contract liabilities (300 ) Short-term lease liabilities, operating leases (1,915 ) Long-term lease liabilities, operating leases (8,873 ) Deferred tax liabilities (1,694 ) Net assets acquired $ 309,501
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 Carrying Amount Amortization Period (in years) Customer relationships $ 34,100 12 Backlog 38,200 3 Developed technologies 2,000 6 Non-compete agreements 650 3
Schedule of Supplemental Pro Forma Information	Supplemental information of unaudited pro forma operating results assuming the Braxton acquisition had been consummated as of the beginning of fiscal year 2019 (in thousands) is as follows: Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Pro forma Revenue $ 879,356 $ 1,003,369 $ 1,754,053 $ 2,004,706 Pro forma Net Income including noncontrolling interests 12,575 31,141 $ 27,929 $ 45,600

Contracts with Customers (Table

Contracts with Customers (Tables)	6 Months Ended
	Jun. 30, 2021
Revenue From Contract With Customer [Abstract]
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): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Fixed-Price $ 233,231 $ 311,368 $ 463,173 $ 619,676 Time-and-Materials 253,365 259,381 493,030 511,820 Cost-Plus 392,760 408,710 797,850 818,956 Total $ 879,356 $ 979,459 $ 1,754,053 $ 1,950,452
Summary of Contract Assets and Contract Liabilities	Contract assets and contract liabilities balances at June 30, 2021 and December 31, 2020 were as follows (in thousands): June 30, 2021 December 31, 2020 $ change % change Contract assets $ 568,239 $ 576,568 $ (8,329 ) -1.4 % Contract liabilities 196,547 201,864 (5,317 ) -2.6 % Net contract assets (liabilities) (1) $ 371,692 $ 374,704 $ (3,012 ) -0.8 % (1) Total contract retentions included in net contract assets (liabilities) were $94.7 million
Summary of Changes in Contract Assets and Contract Liabilities	Certain changes in contract assets and contract liabilities consisted of the following: June 30, 2021 December 31, 2020 Acquired contract assets $ - $ 8,350 Acquired contract liabilities - 300
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: Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue impact, net $ (20,827 ) $ 8,983 $ (20,827 ) $ 8,983
Summary of Accounts Receivable, Net	Accounts receivable, net consisted of the following as of June 30, 2021 and December 31, 2020 (in thousands): 2021 2020 Billed $ 458,686 $ 512,357 Unbilled 183,293 190,222 Total accounts receivable, gross 641,979 702,579 Allowance for doubtful accounts (3,999 ) (4,001 ) Total accounts receivable, net $ 637,980 $ 698,578
Summary of Remaining Unsatisfied Performance Obligations Expect to Satisfy	The Company expects to satisfy its RUPO as of June 30, 2021 over the following periods (in thousands): Period RUPO Will Be Satisfied Within One Year Within One to Two Years Thereafter Federal Solutions $ 1,071,149 $ 461,928 $ 355,680 Critical Infrastructure 1,581,878 760,048 861,020 Total $ 2,653,027 $ 1,221,976 $ 1,216,700

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2021
Leases [Abstract]
Summary of Lease Costs	The components of lease costs for the three and six months ended June 30, 2021 and June 30, 2020 are as follows (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Operating lease cost $ 16,050 $ 15,755 $ 32,377 $ 33,026 Short-term lease cost 2,264 4,301 4,330 7,952 Amortization of right-of-use assets 543 251 1,017 505 Interest on lease liabilities 28 22 57 46 Sublease income (793 ) (932 ) (1,569 ) (1,812 ) Total lease cost $ 18,092 $ 19,397 $ 36,212 $ 39,717
Schedule of Supplemental Cash Flow Information Related to Leases	Supplemental cash flow information related to leases for the six months ended June 30, 2021 and June 30, 2020 is as follows (in thousands): Six Months Ended June 30, 2021 June 30, 2020 Operating cash flows for operating leases $ 33,035 $ 30,676 Operating cash flows for finance leases 58 46 Financing cash flows from finance leases 1,020 553 Right-of-use assets obtained in exchange for new operating lease liabilities 8,328 17,034 Right-of-use assets obtained in exchange for new finance lease liabilities $ 831 $ -
Schedule of Supplemental Balance Sheet and Other Information Related to Leases	Supplemental balance sheet and other information related to leases as of June 30, 2021 and December 31, 2020 are as follows (in thousands): June 30, 2021 December 31, 2020 Operating Leases: Right-of-use assets $ 194,484 $ 210,398 Lease liabilities: Current $ 53,997 $ 54,133 Long-term 164,754 182,467 Total operating lease liabilities $ 218,751 $ 236,600 Finance Leases: Other noncurrent assets $ 3,414 $ 3,363 Accrued expenses and other current liabilities $ 1,598 $ 1,461 Other long-term liabilities $ 1,618 $ 1,733 Weighted Average Remaining Lease Term: Operating leases 4.7 Years 5 years Finance leases 2.5 years 3 years Weighted Average Discount Rate: Operating leases 3.6 % 3.7 % Finance leases 3.0 % 3.8 %
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 June 30, 2021 is as follows (in thousands): Operating Leases Finance Leases 2021 (remaining) $ 30,351 $ 896 2022 58,082 1,358 2023 50,146 684 2024 39,529 274 2025 28,945 106 Thereafter 30,268 3 Total lease payments 237,321 3,321 Less: imputed interest (18,570 ) (105 ) Total present value of lease liabilities $ 218,751 $ 3,216

Goodwill (Tables)

Goodwill (Tables)	6 Months Ended
	Jun. 30, 2021
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 from December 31, 2020 to June 30, 2021 (in thousands): December 31, 2020 Acquisitions Foreign Exchange June 30, 2021 Federal Solutions $ 1,188,882 $ (1,292 ) $ - $ 1,187,590 Critical Infrastructure 73,096 - 2,374 75,470 Total $ 1,261,978 $ (1,292 ) $ 2,374 $ 1,263,060

Intangible Assets (Tables)

Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2021
Goodwill And Intangible Assets Disclosure [Abstract]
Schedule of Gross Amount and Accumulated Amortization of Intangible Assets	The gross amount and accumulated amortization of intangible assets with finite useful lives included in “Intangible assets, net” on the consolidated balance sheets are as follows (in thousands except for years): June 30, 2021 December 31, 2020 Weighted Average Gross Carrying Amount Accumulated Amortization Net Carrying Amount Gross Carrying Amount Accumulated Amortization Net Carrying Amount Amortization Period (in years) Backlog $ 147,455 $ (112,066 ) $ 35,389 $ 145,855 $ (101,038 ) $ 44,817 3 Customer relationships 262,830 (133,908 ) 128,922 264,129 (110,450 ) 153,679 8 Leases 670 (609 ) 61 670 (599 ) 71 5 Developed technology 112,939 (82,793 ) 30,146 112,039 (68,968 ) 43,071 4 Trade name 8,200 (8,167 ) 33 8,200 (7,967 ) 233 1 Non-compete agreements 4,250 (2,688 ) 1,562 4,250 (2,043 ) 2,207 3 In process research and development 1,800 - 1,800 1,800 - 1,800 n/a Other intangibles 275 (203 ) 72 275 (195 ) 80 10 Total intangible assets $ 538,419 $ (340,434 ) $ 197,985 $ 537,218 $ (291,260 ) $ 245,958
Schedule of Estimated Amortization Expense	Estimated amortization expense for the remainder of the current fiscal year and in each of the next four years and beyond is as follows (in thousands): June 30, 2021 2021 $ 48,806 2022 52,230 2023 38,595 2024 12,273 2025 9,713 Thereafter 34,568 Total $ 196,185

Property and Equipment, Net (Ta

Property and Equipment, Net (Tables)	6 Months Ended
	Jun. 30, 2021
Property Plant And Equipment [Abstract]
Schedule of Property and Equipment, Net	Property and equipment consisted of the following at June 30, 2021 and December 31, 2020 (in thousands): June 30, 2021 December 31, 2020 Useful life (years) Buildings and leasehold improvements $ 97,167 $ 98,151 1-15 Furniture and equipment 88,403 91,036 3-10 Computer systems and equipment 164,302 160,305 3-10 Construction equipment 8,635 8,920 5-7 Construction in progress 9,032 9,202 367,539 367,614 Accumulated depreciation (256,922 ) (246,587 ) Property and equipment, net $ 110,617 $ 121,027

Debt and Credit Facilities (Tab

Debt and Credit Facilities (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Schedule of Debt	Debt consisted of the following (in thousands): June 30, 2021 December 31, 2020 Short-Term: Senior notes $ 50,000 $ 50,000 Total Short-Term 50,000 50,000 Long-Term: Senior notes 200,000 200,000 Convertible senior notes 400,000 400,000 Debt discount - (51,138 ) Debt issuance costs (9,124 ) (8,864 ) Total long-term 590,876 539,998 Total Debt $ 640,876 $ 589,998
Schedule of Aggregate Amount of Debt	On July 1, 2014, the Company finalized a private placement whereby the Company raised an aggregate amount of $250.0 million in debt as follows (in thousands): Tranche Debt Amount Maturity Date Interest Rates Senior Note, Series A $ 50,000 July 15, 2021 4.44 % Senior Note, Series B 100,000 July 15, 2024 4.98 % Senior Note, Series C 60,000 July 15, 2026 5.13 % Senior Note, Series D 40,000 July 15, 2029 5.38 %

Investments in and Advances t_2

Investments in and Advances to Joint Ventures (Tables)	6 Months Ended
	Jun. 30, 2021
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 (in thousands): June 30, 2021 December 31, 2020 Current assets $ 263,051 $ 292,407 Noncurrent assets 2,641 2,990 Total assets 265,692 295,397 Current liabilities 191,223 201,270 Total liabilities 191,223 201,270 Total joint venture equity $ 74,469 $ 94,127 Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue $ 98,245 $ 117,889 $ 194,869 $ 218,167 Costs 87,097 101,935 173,403 199,085 Net income $ 11,148 $ 15,954 $ 21,466 $ 19,082 Net income attributable to noncontrolling interests $ 5,325 $ 7,826 $ 10,300 $ 9,224
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 (in thousands): June 30, 2021 December 31, 2020 Current assets $ 1,042,978 $ 774,646 Noncurrent assets 614,916 585,802 Total assets 1,657,894 1,360,448 Current liabilities 805,616 703,287 Noncurrent liabilities 565,249 517,697 Total liabilities 1,370,865 1,220,984 Total joint venture equity $ 287,029 $ 139,464 Investments in and advances to unconsolidated joint ventures $ 86,045 $ 68,975 Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue $ 736,284 $ 238,188 $ 972,801 $ 691,447 Costs 696,198 223,686 907,045 650,691 Net income $ 40,086 $ 14,502 $ 65,756 $ 40,756 Equity in earnings of unconsolidated joint ventures $ 9,428 $ 3,769 $ 16,958 $ 9,883

Related Party Transactions (Tab

Related Party Transactions (Tables)	6 Months Ended
	Jun. 30, 2021
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): June 30, 2021 December 31, 2020 Accounts receivable $ 30,897 $ 37,544 Contract assets 9,161 8,889 Contract liabilities 7,887 5,720

Earnings Per Share (Tables)

Earnings Per Share (Tables)	6 Months Ended
	Jun. 30, 2021
Earnings Per Share [Abstract]
Schedule of Weighted Average Number of Shares Used To Compute Basic and Diluted EPS	The weighted average number of shares used to compute basic and diluted EPS were: Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Basic weighted average number of shares outstanding 102,509,245 100,694,938 102,456,219 100,682,315 Stock-based awards 744,322 290,649 636,162 266,369 Convertible senior notes 8,916,530 - 8,916,530 - Diluted weighted average number of shares outstanding 112,170,097 100,985,587 112,008,911 100,948,684
Net Income Available to Shareholders to Compute Basic and Diluted EPS	The net income available to shareholders to compute basic and diluted EPS were (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Net income attributable to Parsons Corporation 6,702 23,299 15,741 36,272 Convertible senior notes if-converted method interest adjustment 531 - 1,059 - Diluted net income attributable to Parsons Corporation 7,233 23,299 16,800 36,272

Segment Information (Tables)

Segment Information (Tables)	6 Months Ended
	Jun. 30, 2021
Segment Reporting [Abstract]
Summary of Business Segment Information	The following table summarizes business segment revenue for the periods presented (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Federal Solutions revenue $ 442,675 $ 482,210 $ 894,744 $ 959,781 Critical Infrastructure revenue 436,681 497,249 859,309 990,671 Total revenue $ 879,356 $ 979,459 $ 1,754,053 $ 1,950,452
Summary of Adjusted EBITDA Business Segment Information	The following table reconciles business segment Adjusted EBITDA attributable to Parsons Corporation to Net Income attributable to Parsons Corporation for the periods presented (in thousands): Three Months Ended Six Months Ended Adjusted EBITDA attributable to Parsons Corporation June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Federal Solutions $ 32,500 $ 47,700 $ 64,482 $ 79,317 Critical Infrastructure 27,817 35,519 59,474 62,876 Adjusted EBITDA attributable to Parsons Corporation 60,317 83,219 123,956 142,193 Adjusted EBITDA attributable to noncontrolling interests 5,410 7,942 10,470 9,464 Depreciation and amortization (34,635 ) (32,081 ) (69,308 ) (64,490 ) Interest expense, net (4,758 ) (3,963 ) (9,201 ) (7,757 ) Income tax expense (3,838 ) (11,891 ) (9,213 ) (16,975 ) Equity-based compensation expense (4,921 ) (12,854 ) (11,901 ) (5,133 ) Transaction-related costs (a) (4,086 ) 2,485 (6,732 ) (9,526 ) Restructuring expense (b) (73 ) (1,143 ) (150 ) (1,110 ) Other (c) (1,389 ) (589 ) (1,880 ) (1,170 ) Net income including noncontrolling interests 12,027 31,125 26,041 45,496 Net income attributable to noncontrolling interests 5,325 7,826 10,300 9,224 Net income attributable to Parsons Corporation $ 6,702 $ 23,299 $ 15,741 $ 36,272 (a) Reflects costs incurred in connection with acquisitions and other non-recurring transaction costs, primarily fees paid for professional services and employee retention. (b) Reflects costs associated with corporate restructuring initiatives. (c) 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 tables present revenues and property and equipment, net by geographic area (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue North America $ 725,047 $ 800,044 $ 1,441,393 $ 1,597,990 Middle East 147,675 174,689 301,318 343,548 Rest of World 6,634 4,726 11,342 8,914 Total Revenue $ 879,356 $ 979,459 $ 1,754,053 $ 1,950,452 The geographic location of revenue is determined by the location of the customer. June 30, 2021 December 31, 2020 Property and Equipment, Net North America $ 106,737 $ 116,460 Middle East 3,880 4,567 Total Property and Equipment, Net $ 110,617 $ 121,027
Summary of Revenues by Business Lines	The following table presents revenues by business units (in thousands): Three Months Ended Six Months Ended June 30, 2021 June 30, 2020 June 30, 2021 June 30, 2020 Revenue Cyber & Intelligence $ 85,282 $ 102,993 $ 168,610 $ 201,875 Space & Geospatial Solutions 77,614 57,967 160,673 109,255 Missile Defense & C5ISR 145,493 154,767 290,208 309,336 Engineered Systems 134,286 166,483 275,253 339,315 Federal Solutions revenues 442,675 482,210 894,744 959,781 Connected Communities 81,321 98,359 171,204 200,260 Mobility Solutions 355,360 398,890 688,105 790,411 Critical Infrastructure revenues 436,681 497,249 859,309 990,671 Total Revenue $ 879,356 $ 979,459 $ 1,754,053 $ 1,950,452

Basis of Presentation and Pri_3

Basis of Presentation and Principles of Consolidation - Additional Information (Details)	3 Months Ended
	Jun. 30, 2020
Employee Stock Purchase Plan | Maximum
Basis Of Presentation And Principles Of Consolidation Disclosure [Line Items]
Percentage of per-share market value limit for share purchases	5.00%

New Accounting Pronouncements -

New Accounting Pronouncements - Additional Information (Details)	Jun. 30, 2021
ASU 2020-06
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 1, 2021
Change in accounting principle, accounting standards update, early adoption	true
Change in accounting principle, accounting standards update, immaterial effect	false
ASU 2019-12
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 1, 2021
Change in accounting principle, accounting standards update, immaterial effect	true
Change in accounting principle, accounting standards update, adopted	true
ASU 2016-13
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in accounting principle, accounting standards update, adoption date	Jan. 1, 2020
Change in accounting principle, accounting standards update, immaterial effect	true
Change in accounting principle, accounting standards update, adopted	true

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - USD ($) $ in Thousands	Nov. 19, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Business Acquisition [Line Items]
Amortization of intangible assets		$ 24,500	$ 22,100	$ 49,000	$ 44,800
Revenues		879,356	$ 979,459	1,754,053	$ 1,950,452
Braxton Science & Technology Group
Business Acquisition [Line Items]
Percentage of ownership interest acquired	100.00%
Cash paid to acquire	$ 309,500
Amortization of intangible assets		4,000		8,100
Goodwill deductible for tax purposes	$ 196,300
Revenues		$ 29,300		60,300
Selling, General and Administrative Expense | Braxton Science & Technology Group
Business Acquisition [Line Items]
Acquisition related expenses				$ 600

Acquisitions - Summary of Estim

Acquisitions - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed on Preliminary Purchase Price Allocation (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Nov. 19, 2020
Business Acquisition [Line Items]
Contract assets	$ 568,239	$ 576,568
Goodwill	1,263,060	1,261,978
Contract liabilities	$ (196,547)	$ (201,864)
Braxton Science & Technology Group
Business Acquisition [Line Items]
Cash and cash equivalents			$ 7,006
Accounts receivable			18,163
Contract assets			8,350
Prepaid expenses and other current assets			3,036
Property and equipment			5,114
Right of use assets, operating leases			10,788
Goodwill			212,185
Intangible assets			74,950
Accounts payable			(7,464)
Accrued expenses and other current liabilities			(9,845)
Contract liabilities			(300)
Short-term lease liabilities, operating leases			(1,915)
Long-term lease liabilities, operating leases			(8,873)
Deferred tax liabilities			(1,694)
Net assets acquired			$ 309,501

Acquisitions - Schedule of Inta

Acquisitions - Schedule of Intangible Assets Value on Purchase Price (Details) - USD ($) $ in Thousands	Nov. 19, 2020	Jun. 30, 2021
Customer Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)		8 years
Customer Relationships | Braxton Science & Technology Group
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 34,100
Amortization Period (in years)	12 years
Backlog
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)		3 years
Backlog | Braxton Science & Technology Group
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 38,200
Amortization Period (in years)	3 years
Non compete Agreements
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)		3 years
Non compete Agreements | Braxton Science & Technology Group
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 650
Amortization Period (in years)	3 years
Developed Technologies
Acquired Finite Lived Intangible Assets [Line Items]
Amortization Period (in years)		4 years
Developed Technologies | Braxton Science & Technology Group
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 2,000
Amortization Period (in years)	6 years

Acquisitions - Schedule of Supp

Acquisitions - Schedule of Supplemental Pro Forma Information (Details) - Braxton Science & Technology Group - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Business Acquisition [Line Items]
Pro forma Revenue	$ 879,356	$ 1,003,369	$ 1,754,053	$ 2,004,706
Pro forma Net Income including noncontrolling interests	$ 12,575	$ 31,141	$ 27,929	$ 45,600

Contracts with Customers - Summ

Contracts with Customers - Summary of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation Of Revenue [Line Items]
Revenues	$ 879,356	$ 979,459	$ 1,754,053	$ 1,950,452
Fixed-Price
Disaggregation Of Revenue [Line Items]
Revenues	233,231	311,368	463,173	619,676
Time-and-Materials
Disaggregation Of Revenue [Line Items]
Revenues	253,365	259,381	493,030	511,820
Cost-Plus
Disaggregation Of Revenue [Line Items]
Revenues	$ 392,760	$ 408,710	$ 797,850	$ 818,956

Contracts with Customers - Su_2

Contracts with Customers - Summary of Contract Assets and Contract Liabilities (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Contract assets	$ 568,239	$ 576,568
Contract liabilities	196,547	201,864
Net contract assets (liabilities)	371,692	$ 374,704
Change in contract assets	(8,329)
Change in contract liabilities	(5,317)
Change in contract assets and liabilities	$ (3,012)
Percentage change in contract assets	(1.40%)
Percentage change in contract liabilities	(2.60%)
Percentage change in contract assets and liabilities	(0.80%)

Contracts with Customers - Su_3

Contracts with Customers - Summary of Contract Assets and Contract Liabilities (Parenthetical) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Contract retentions	$ 94.7	$ 93.8
Contract retentions, not expected to be paid in next 12 months	50.8
Contract assets, unapproved change orders, claims, and requests	$ 103.4	$ 116.6

Contracts with Customers - Addi

Contracts with Customers - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue From Contract With Customer [Abstract]
Revenue recognized included contract liability	$ 23,500,000	$ 28,400,000	$ 92,600,000	$ 122,700,000
Impairment of contract assets	0	$ 0	0	$ 0
Impact of changes in estimated claims or incentives on revenue			5,000,000
Remaining unsatisfied performance obligations	$ 5,100,000,000		$ 5,100,000,000

Contracts with Customers - Su_4

Contracts with Customers - Summary of Changes in Contract Assets and Contract Liabilities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Revenue From Contract With Customer [Abstract]
Acquired contract assets	$ 8,350
Acquired contract liabilities	$ 300

Contracts with Customers - Su_5

Contracts with Customers - Summary of Changes in Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Revenue From Contract With Customer [Abstract]
Revenue impact, net	$ (20,827)	$ 8,983	$ (20,827)	$ 8,983

Contracts with Customers - Su_6

Contracts with Customers - Summary of Accounts Receivable, Net (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Revenue From Contract With Customer [Abstract]
Billed	$ 458,686	$ 512,357
Unbilled	183,293	190,222
Total accounts receivable, gross	641,979	702,579
Allowance for doubtful accounts	(3,999)	(4,001)
Total accounts receivable, net	$ 637,980	$ 698,578

Contracts with Customers - Su_7

Contracts with Customers - Summary of Remaining Unsatisfied Performance Obligations Expect to Satisfy (Details) $ in Thousands	Jun. 30, 2021USD ($)
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 5,100,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-07-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 2,653,027
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,221,976
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,216,700
Revenue, remaining performance obligation, expected timing of satisfaction, period
Federal Solution Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-07-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,071,149
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Federal Solution Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 461,928
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Federal Solution Segment | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 355,680
Revenue, remaining performance obligation, expected timing of satisfaction, period
Critical Infrastructure | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-07-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 1,581,878
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Critical Infrastructure | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 760,048
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Critical Infrastructure | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01
Revenue Remaining Performance Obligation Expected Timing Of Satisfaction [Line Items]
Remaining unsatisfied performance obligations	$ 861,020
Revenue, remaining performance obligation, expected timing of satisfaction, period

Leases - Additional Information

Leases - Additional Information (Details)	6 Months Ended
	Jun. 30, 2021USD ($)
Lessee Lease Description [Line Items]
Lease option to extend	five years
Lease existence of option to extend	true
Lease option to terminate	third year
Lease existence of option to terminate	true
Operating lease not yet commenced expense	$ 0
Minimum
Lessee Lease Description [Line Items]
Lease term of contract	1 year
Maximum
Lessee Lease Description [Line Items]
Lease term of contract	9 years

Leases - Summary of Lease Costs

Leases - Summary of Lease Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Operating lease cost	$ 16,050	$ 15,755	$ 32,377	$ 33,026
Short-term lease cost	2,264	4,301	4,330	7,952
Amortization of right-of-use assets	543	251	1,017	505
Interest on lease liabilities	28	22	57	46
Sublease income	(793)	(932)	(1,569)	(1,812)
Total lease cost	$ 18,092	$ 19,397	$ 36,212	$ 39,717

Leases - Schedule of Supplement

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Operating cash flows for operating leases	$ 33,035	$ 30,676
Operating cash flows for finance leases	58	46
Financing cash flows from finance leases	1,020	553
Right-of-use assets obtained in exchange for new operating lease liabilities	8,328	17,034
Right-of-use assets obtained in exchange for new finance lease liabilities	$ 831	$ 0

Leases - Schedule of Suppleme_2

Leases - Schedule of Supplemental Balance Sheet and Other Information Related to Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Operating Leases:
Right-of-use assets	$ 194,484	$ 210,398
Lease liabilities:
Current	53,997	54,133
Long-term	164,754	182,467
Total operating lease liabilities	218,751	236,600
Finance Leases:
Other noncurrent assets	3,414	3,363
Accrued expenses and other current liabilities	$ 1,598	$ 1,461
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	psn:AccruedExpensesAndOtherCurrentLiabilities	psn:AccruedExpensesAndOtherCurrentLiabilities
Other long-term liabilities	$ 1,618	$ 1,733
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Other long-term liabilities	Other long-term liabilities
Weighted Average Remaining Lease Term:
Operating leases	4 years 8 months 12 days	5 years
Finance leases	2 years 6 months	3 years
Weighted Average Discount Rate:
Operating leases	3.60%	3.70%
Finance leases	3.00%	3.80%

Leases - Schedule of Maturity A

Leases - Schedule of Maturity Analysis of Future Undiscounted Cash Flows (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Operating Leases
2021 (remaining)	$ 30,351
2022	58,082
2023	50,146
2024	39,529
2025	28,945
Thereafter	30,268
Total lease payments	237,321
Less: imputed interest	(18,570)
Total present value of lease liabilities	218,751	$ 236,600
Finance Leases
2021 (remaining)	896
2022	1,358
2023	684
2024	274
2025	106
Thereafter	3
Total lease payments	3,321
Less: imputed interest	(105)
Total present value of lease liabilities	$ 3,216

Goodwill - Summary of Changes i

Goodwill - Summary of Changes in Carrying Value of Goodwill by Reporting Segment (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2021USD ($)
Goodwill [Line Items]
Beginning Balance	$ 1,261,978
Acquisitions	(1,292)
Foreign Exchange	2,374
Ending Balance	1,263,060
Federal Solutions
Goodwill [Line Items]
Beginning Balance	1,188,882
Acquisitions	(1,292)
Ending Balance	1,187,590
Critical Infrastructure
Goodwill [Line Items]
Beginning Balance	73,096
Foreign Exchange	2,374
Ending Balance	$ 75,470

Goodwill - Additional Informati

Goodwill - Additional Information (Details)	6 Months Ended
	Jun. 30, 2021USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
Impairment of goodwill	$ 0

Intangible Assets - Schedule of

Intangible Assets - Schedule of Gross Amount and Accumulated Amortization of Intangible Assets (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 538,419	$ 537,218
Accumulated Amortization	(340,434)	(291,260)
Net Carrying Amount	197,985	245,958
Backlog
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	147,455	145,855
Accumulated Amortization	(112,066)	(101,038)
Net Carrying Amount	$ 35,389	44,817
Amortization Period (in years)	3 years
Customer Relationships
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 262,830	264,129
Accumulated Amortization	(133,908)	(110,450)
Net Carrying Amount	$ 128,922	153,679
Amortization Period (in years)	8 years
Leases
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 670	670
Accumulated Amortization	(609)	(599)
Net Carrying Amount	$ 61	71
Amortization Period (in years)	5 years
Developed Technology
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 112,939	112,039
Accumulated Amortization	(82,793)	(68,968)
Net Carrying Amount	$ 30,146	43,071
Amortization Period (in years)	4 years
Trade Name
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 8,200	8,200
Accumulated Amortization	(8,167)	(7,967)
Net Carrying Amount	$ 33	233
Amortization Period (in years)	1 year
Non compete Agreements
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 4,250	4,250
Accumulated Amortization	(2,688)	(2,043)
Net Carrying Amount	$ 1,562	2,207
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
Net Carrying Amount	1,800	1,800
Other Intangibles
Acquired Finite Lived Intangible Assets [Line Items]
Gross Carrying Amount	275	275
Accumulated Amortization	(203)	(195)
Net Carrying Amount	$ 72	$ 80
Amortization Period (in years)	10 years

Intangible Assets - Additional

Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense of intangible assets	$ 24.5	$ 22.1	$ 49	$ 44.8

Intangible Assets - Schedule _2

Intangible Assets - Schedule of Estimated Amortization Expense (Details) $ in Thousands	Jun. 30, 2021USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2021	$ 48,806
2022	52,230
2023	38,595
2024	12,273
2025	9,713
Thereafter	34,568
Finite-Lived Intangible Assets, Net	$ 196,185

Property and Equipment, Net - S

Property and Equipment, Net - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 367,539	$ 367,614
Accumulated depreciation	(256,922)	(246,587)
Property and equipment, net	110,617	121,027
Buildings and Leasehold Improvements
Property Plant And Equipment [Line Items]
Property and equipment, gross	$ 97,167	98,151
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	$ 88,403	91,036
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	$ 164,302	160,305
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	$ 8,635	8,920
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	$ 9,032	$ 9,202

Property and Equipment, Net - A

Property and Equipment, Net - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Property Plant And Equipment [Abstract]
Depreciation expense	$ 9.5	$ 9.8	$ 19.2	$ 19.4

Debt and Credit Facilities - Sc

Debt and Credit Facilities - Schedule of Debt (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Short-term debt	$ 50,000	$ 50,000
Convertible senior notes	400,000	400,000
Debt discount		(51,138)
Long-term debt issuance costs	(9,124)	(8,864)
Total long-term	590,876	539,998
Total Debt	640,876	589,998
Senior Notes
Debt Instrument [Line Items]
Short-Term	50,000	50,000
Long-term debt	$ 200,000	$ 200,000

Debt and Credit Facilities - Ad

Debt and Credit Facilities - Additional Information (Details)	Jul. 01, 2014USD ($)	Jul. 31, 2021USD ($)	Jun. 30, 2021USD ($)Extension$ / shares	Aug. 31, 2020USD ($)d$ / sharesshares	Jun. 30, 2021USD ($)$ / shares	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)d$ / sharesshares	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)	Mar. 31, 2021USD ($)	Jan. 01, 2021USD ($)	Aug. 10, 2020USD ($)
Debt Instrument [Line Items]
Letters of credit outstanding amount			$ 219,200,000		$ 219,200,000		$ 219,200,000		$ 193,100,000
Deferred tax liabilities			12,690,000		12,690,000		12,690,000		12,285,000
Deferred tax assets			147,146,000		147,146,000		147,146,000		130,200,000
Level 2
Debt Instrument [Line Items]
Senior notes, fair value			273,900,000		273,900,000		273,900,000
Senior Notes
Debt Instrument [Line Items]
Debt instrument, outstanding amount			200,000,000		200,000,000		200,000,000		200,000,000
Senior Note, Series A | Subsequent Event
Debt Instrument [Line Items]
Senior note, amount paid		$ 50,000,000
Convertible Senior Notes
Debt Instrument [Line Items]
Interest rate				0.25%
Interest expense					700,000		$ 1,500,000		4,400,000
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		$ 1,000		$ 1,000
Convertible notes converted each into shares of common stock | shares							22.2913
Debt Instrument, conversion price | $ / shares			$ 44.86		$ 44.86		$ 44.86
Threshold trading days | d				20			51
Threshold consecutive trading days | d				30
Conversion percentage of stock price trigger				130.00%
Number of business day period				5 days
Consecutive trading day period				5 days
Convertible principal amount				$ 1,000
Measurement period, percentage				98.00%
Percentage of principal amount to redeem convertible senior notes				100.00%
Percentage of convertible senior notes repurchased at cash				100.00%
Debt liability				$ 336,100,000
Debt instrument convertible notes additional paid in capital				$ 53,600,000
Convertible senior notes effective interest rate				3.25%
Net carrying value of notes			$ 400,000,000		$ 400,000,000		$ 400,000,000		340,600,000
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		$ 66.46		$ 66.46
Cash proceeds from sales of warrants							$ 13,800,000
Convertible Senior Notes | ASU 2020-06
Debt Instrument [Line Items]
Reclassification of equity component of convertible senior notes to liabilities										$ 55,000,000
Reclassification of equity component of debt issuance costs to liabilities										$ 1,400,000
Carrying amount of convertible senior notes adjusted in retained earnings											$ 3,700,000
Convertible Note Hedge And Warrant Transaction
Debt Instrument [Line Items]
Purchase of bond hedges and sale of warrants				$ 41,200,000
Deferred tax liabilities			$ 16,200,000		$ 16,200,000		16,200,000
Deferred tax assets			16,500,000		16,500,000		16,500,000
Convertible Note Hedge And Warrant Transaction | ASU 2020-06
Debt Instrument [Line Items]
Deferred tax liability reversed			13,900,000		13,900,000		13,900,000
Additional deferred tax liability related to capitalized debt issuance costs			400,000		400,000		400,000
Adjustment to deferred tax asset through retained earnings			900,000		900,000		900,000
Private Placement
Debt Instrument [Line Items]
Debt issuance costs incurred	$ 1,100,000											$ 500,000
Debt amount	250,000,000
Private Placement | Accrued Expenses and Other Current Liabilities
Debt Instrument [Line Items]
Interest payable			$ 5,500,000		5,500,000		5,500,000		$ 5,500,000
Private Placement | Senior Notes
Debt Instrument [Line Items]
Interest expense					3,100,000	$ 3,100,000	6,200,000	$ 6,200,000
Interest payments					6,200,000	6,200,000	6,200,000	6,200,000
Private Placement | Senior Note, Series A
Debt Instrument [Line Items]
Debt amount	$ 50,000,000
Maturity Date	Jul. 15, 2021
Minimum | Convertible Senior Notes
Debt Instrument [Line Items]
Debt Instrument, conversion price | $ / shares				$ 44.86
Percentage of bond hedge and warrant transactions increased conversion price				35.00%
Maximum | Convertible Senior Notes
Debt Instrument [Line Items]
Debt Instrument, conversion price | $ / shares				$ 66.46
Percentage of bond hedge and warrant transactions increased conversion price				100.00%
Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Credit agreement date			Jun. 30, 2021
Revolving credit facility			$ 650,000,000		650,000,000		650,000,000
Debt issuance costs incurred			2,000,000		2,000,000		2,000,000
Revolving credit facility			$ 550,000,000		$ 550,000,000		$ 550,000,000
Credit agreement maturity period			5 years
Credit agreement number of extensions | Extension			2
Interest rate			1.34%		1.34%		1.34%		1.87%
Letters of credit outstanding amount			$ 45,000,000		$ 45,000,000		$ 45,000,000		$ 44,900,000
Interest expense					300,000	$ 300,000	500,000	$ 700,000
Debt instrument, outstanding amount			$ 0		$ 0		$ 0
Unsecured Revolving Credit Facility | Base Rate | Minimum
Debt Instrument [Line Items]
Margin interest rate							0.00%
Unsecured Revolving Credit Facility | Base Rate | Maximum
Debt Instrument [Line Items]
Margin interest rate							0.625%
Unsecured Revolving Credit Facility | Euro Currency Rate | Minimum
Debt Instrument [Line Items]
Margin interest rate							1.00%
Unsecured Revolving Credit Facility | Euro Currency Rate | Maximum
Debt Instrument [Line Items]
Margin interest rate							1.625%

Debt and Credit Facilities - _2

Debt and Credit Facilities - Schedule of Aggregate Amount of Debt (Details) - Private Placement $ in Thousands	Jul. 01, 2014USD ($)
Debt Instrument [Line Items]
Debt Amount	$ 250,000
Senior Note, Series A
Debt Instrument [Line Items]
Debt Amount	$ 50,000
Maturity Date	Jul. 15, 2021
Interest Rates	4.44%
Senior Note, Series B
Debt Instrument [Line Items]
Debt Amount	$ 100,000
Maturity Date	Jul. 15, 2024
Interest Rates	4.98%
Senior Note, Series C
Debt Instrument [Line Items]
Debt Amount	$ 60,000
Maturity Date	Jul. 15, 2026
Interest Rates	5.13%
Senior Note, Series D
Debt Instrument [Line Items]
Debt Amount	$ 40,000
Maturity Date	Jul. 15, 2029
Interest Rates	5.38%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Effective income tax rate	24.20%	27.60%	26.10%	27.20%
U.S. corporate tax rate	21.00%		21.00%
Deferred tax assets, valuation allowance	$ 31.3		$ 31.3
Liability for income taxes associated with uncertain tax positions	18		18		$ 16.4
Decrease in uncertain tax positions during the next twelve months	$ 0.2		$ 0.2

Contingencies - Additional Info

Contingencies - Additional Information (Details)	Mar. 01, 2017USD ($)	Jun. 30, 2021Claim
Legal Proceedings [Line Items]
Number of claims outstanding | Claim		0
Minimum
Legal Proceedings [Line Items]
Loss contingency damages value | $	$ 100,000,000

Retirement Benefit Plan - Addit

Retirement Benefit Plan - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
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	102,502,780		102,502,780		102,360,662
Company's stock held by ESOP	72,288,913		72,288,913		76,641,312
Direct Costs of Contracts and Selling, General and Administrative Expense
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
ESOP contribution expense	$ 13.4	$ 14.6	$ 26.5	$ 29.5

Investments in and Advances t_3

Investments in and Advances to Joint Ventures - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Schedule Of Equity Method Investments [Line Items]
Letters of credit outstanding amount	$ 219.2		$ 219.2		$ 193.1
Write-down on unconsolidated joint venture	1.6		5.1
Decrease in operating income	1.6		5.1
Decrease in net income net of tax	$ 1.2		$ 3.8
Decrease in earnings per share diluted	$ 0.01		$ 0.03
Unconsolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Net distributions from and sale proceeds for unconsolidated joint ventures	$ 1.5	$ 5.6	$ 6.8	$ 12.1
Consolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Letters of credit outstanding amount	$ 67.5		$ 67.5		$ 59.3

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 1,794,406		$ 1,794,406		$ 1,843,130
Total assets	3,839,297		3,839,297		3,937,704
Current liabilities	1,077,424		1,077,424		1,187,409
Total liabilities	1,988,847		1,988,847		2,076,287
Total joint venture equity	1,813,465		1,813,465		1,813,772
Revenue	879,356	$ 979,459	1,754,053	$ 1,950,452
Costs	680,328	749,324	1,349,410	1,518,956
Net income attributable to Parsons Corporation	6,702	23,299	15,741	36,272
Net income attributable to noncontrolling interests	5,325	7,826	10,300	9,224
Consolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Current assets	263,051		263,051		292,407
Noncurrent assets	2,641		2,641		2,990
Total assets	265,692		265,692		295,397
Current liabilities	191,223		191,223		201,270
Total liabilities	191,223		191,223		201,270
Total joint venture equity	74,469		74,469		$ 94,127
Revenue	98,245	117,889	194,869	218,167
Costs	87,097	101,935	173,403	199,085
Net income attributable to Parsons Corporation	11,148	15,954	21,466	19,082
Net income attributable to noncontrolling interests	$ 5,325	$ 7,826	$ 10,300	$ 9,224

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		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 1,794,406		$ 1,794,406		$ 1,843,130
Total assets	3,839,297		3,839,297		3,937,704
Current liabilities	1,077,424		1,077,424		1,187,409
Total liabilities	1,988,847		1,988,847		2,076,287
Total joint venture equity	1,813,465		1,813,465		1,813,772
Investments in and advances to unconsolidated joint ventures	86,045		86,045		68,975
Revenue	879,356	$ 979,459	1,754,053	$ 1,950,452
Costs	680,328	749,324	1,349,410	1,518,956
Net income attributable to Parsons Corporation	6,702	23,299	15,741	36,272
Equity in earnings of unconsolidated joint ventures	9,428	3,769	16,958	9,883
Unconsolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Current assets	1,042,978		1,042,978		774,646
Noncurrent assets	614,916		614,916		585,802
Total assets	1,657,894		1,657,894		1,360,448
Current liabilities	805,616		805,616		703,287
Noncurrent liabilities	565,249		565,249		517,697
Total liabilities	1,370,865		1,370,865		1,220,984
Total joint venture equity	287,029		287,029		139,464
Investments in and advances to unconsolidated joint ventures	86,045		86,045		$ 68,975
Revenue	736,284	238,188	972,801	691,447
Costs	696,198	223,686	907,045	650,691
Net income attributable to Parsons Corporation	40,086	14,502	65,756	40,756
Equity in earnings of unconsolidated joint ventures	$ 9,428	$ 3,769	$ 16,958	$ 9,883

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) - Unconsolidated joint ventures - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Related Party Transaction [Line Items]
Revenues	$ 40.5	$ 42.4	$ 82.4	$ 82.8
Reimbursable cost incurred	$ 30.6	$ 34.6	$ 61.9	$ 66.1

Related Party Transactions - Sc

Related Party Transactions - Schedule of Consolidated Balance Sheet Related to Services Provided to Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Contract assets	$ 568,239	$ 576,568
Contract liabilities	196,547	201,864
Unconsolidated Joint Ventures
Related Party Transaction [Line Items]
Accounts receivable	30,897	37,544
Contract assets	9,161	8,889
Contract liabilities	$ 7,887	$ 5,720

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Stock-based Awards
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share	9,271	4,939	1,644	4,066

Earnings Per Share - Schedule o

Earnings Per Share - Schedule of Weighted Average Number of Shares Used To Compute Basic and Diluted EPS (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Basic weighted average number of shares outstanding	102,509,245	100,694,938	102,456,219	100,682,315
Stock-based awards	744,322	290,649	636,162	266,369
Convertible senior notes	8,916,530	0	8,916,530	0
Diluted weighted average number of shares outstanding	112,170,097	100,985,587	112,008,911	100,948,684

Earnings Per Share - Net Income

Earnings Per Share - Net Income Available to Shareholders to Compute Basic and Diluted EPS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Earnings Per Share [Abstract]
Net income attributable to Parsons Corporation	$ 6,702	$ 23,299	$ 15,741	$ 36,272
Convertible senior notes if-converted method interest adjustment	531		1,059
Diluted net income attributable to Parsons Corporation	$ 7,233	$ 23,299	$ 16,800	$ 36,272

Segment Information - Additiona

Segment Information - Additional Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021USD ($)	Jun. 30, 2020USD ($)	Jun. 30, 2021USD ($)segment	Jun. 30, 2020USD ($)	Dec. 31, 2020USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment			2
Revenues	$ 879,356	$ 979,459	$ 1,754,053	$ 1,950,452
Property and equipment, net	110,617		110,617		$ 121,027
United States
Segment Reporting Information [Line Items]
Revenues	656,200	$ 737,400	1,300,000	$ 1,500,000
Property and equipment, net	$ 100,500		$ 100,500		$ 109,600

Segment Information - Summary o

Segment Information - Summary of Business Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Total revenue	$ 879,356	$ 979,459	$ 1,754,053	$ 1,950,452
Federal Solution Segment
Segment Reporting Information [Line Items]
Total revenue	442,675	482,210	894,744	959,781
Critical Infrastructure
Segment Reporting Information [Line Items]
Total revenue	$ 436,681	$ 497,249	$ 859,309	$ 990,671

Segment Information - Summary_2

Segment Information - Summary of Adjusted EBITDA Business Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Adjusted EBITDA attributable to Parsons Corporation
Adjusted EBITDA attributable to Parsons Corporation	$ 60,317	$ 83,219	$ 123,956	$ 142,193
Adjusted EBITDA attributable to noncontrolling interests	5,410	7,942	10,470	9,464
Depreciation and amortization	(34,635)	(32,081)	(69,308)	(64,490)
Interest expense, net	(4,758)	(3,963)	(9,201)	(7,757)
Income tax expense	(3,838)	(11,891)	(9,213)	(16,975)
Equity-based compensation expense	(4,921)	(12,854)	(11,901)	(5,133)
Transaction-related costs	(4,086)	2,485	(6,732)	(9,526)
Restructuring expense	(73)	(1,143)	(150)	(1,110)
Other	(1,389)	(589)	(1,880)	(1,170)
Net income including noncontrolling interests	12,027	31,125	26,041	45,496
Net income attributable to noncontrolling interests	5,325	7,826	10,300	9,224
Net income attributable to Parsons Corporation	6,702	23,299	15,741	36,272
Federal Solution Segment
Adjusted EBITDA attributable to Parsons Corporation
Adjusted EBITDA attributable to Parsons Corporation	32,500	47,700	64,482	79,317
Critical Infrastructure
Adjusted EBITDA attributable to Parsons Corporation
Adjusted EBITDA attributable to Parsons Corporation	$ 27,817	$ 35,519	$ 59,474	$ 62,876

Segment Information - Summary_3

Segment Information - Summary of Revenues and Property and Equipment, Net by Geographic Area (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Revenues	$ 879,356	$ 979,459	$ 1,754,053	$ 1,950,452
Property and Equipment, Net	110,617		110,617		$ 121,027
North America
Segment Reporting Information [Line Items]
Revenues	725,047	800,044	1,441,393	1,597,990
Property and Equipment, Net	106,737		106,737		116,460
Middle East
Segment Reporting Information [Line Items]
Revenues	147,675	174,689	301,318	343,548
Property and Equipment, Net	3,880		3,880		$ 4,567
Rest of World
Segment Reporting Information [Line Items]
Revenues	$ 6,634	$ 4,726	$ 11,342	$ 8,914

Segment Information - Summary_4

Segment Information - Summary of Revenues by Business Lines (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Revenues	$ 879,356	$ 979,459	$ 1,754,053	$ 1,950,452
Federal Solution Segment
Segment Reporting Information [Line Items]
Revenues	442,675	482,210	894,744	959,781
Federal Solution Segment | Cyber & Intelligence
Segment Reporting Information [Line Items]
Revenues	85,282	102,993	168,610	201,875
Federal Solution Segment | Space & Geospatial Solutions
Segment Reporting Information [Line Items]
Revenues	77,614	57,967	160,673	109,255
Federal Solution Segment | Missile Defense & C5ISR
Segment Reporting Information [Line Items]
Revenues	145,493	154,767	290,208	309,336
Federal Solution Segment | Engineered Systems
Segment Reporting Information [Line Items]
Revenues	134,286	166,483	275,253	339,315
Critical Infrastructure
Segment Reporting Information [Line Items]
Revenues	436,681	497,249	859,309	990,671
Critical Infrastructure | Connected Communities
Segment Reporting Information [Line Items]
Revenues	81,321	98,359	171,204	200,260
Critical Infrastructure | Mobility Solutions
Segment Reporting Information [Line Items]
Revenues	$ 355,360	$ 398,890	$ 688,105	$ 790,411

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Subsequent Event - USD ($) $ in Millions	Jul. 30, 2021	Jul. 06, 2021
BlackHorse Solutions, Inc.
Subsequent Event [Line Items]
Purchase price paid in cash		$ 203
Echo Ridge LLC
Subsequent Event [Line Items]
Purchase price paid in cash	$ 9