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 Capital Revision 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 Equity Revision of Prior Period, Accounting Standards Update, Adjustment	Noncontrolling Interest
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
Beginning balance at Dec. 31, 2021	1,937,112		146,277	(867,391)	2,684,979		(53,529)		(9,568)	1,900,768		36,344
Comprehensive income
Net income	46,623						38,962			38,962		7,661
Foreign currency translation gain (loss), net	(2,509)								(2,507)	(2,507)		(2)
Pension adjustments, net	(25)								(25)	(25)
Contributions	2,827											2,827
Distributions	(10,344)											(10,344)
Issuance of equity securities, net of retirements	(1,827)		324		(2,153)		2			(1,827)
Repurchases of common stock	(15,548)		(427)		(15,121)					(15,548)
Stock-based compensation	8,358				8,358					8,358
Ending Balance at Jun. 30, 2022	1,964,667		146,174	(867,391)	2,676,063		(14,565)		(12,100)	1,928,181		36,486
Beginning balance at Mar. 31, 2022	1,950,625		146,348	(867,391)	2,678,761		(32,858)		(6,673)	1,918,187		32,438
Comprehensive income
Net income	22,780						18,295			18,295		4,485
Foreign currency translation gain (loss), net	(5,383)								(5,380)	(5,380)		(3)
Pension adjustments, net	(47)								(47)	(47)
Contributions	1,601											1,601
Distributions	(2,035)											(2,035)
Issuance of equity securities, net of retirements	2,666		102		2,566		(2)			2,666
Repurchases of common stock	(10,000)		(276)		(9,724)					(10,000)
Stock-based compensation	4,460				4,460					4,460
Ending Balance at Jun. 30, 2022	$ 1,964,667		$ 146,174	$ (867,391)	$ 2,676,063		$ (14,565)		$ (12,100)	$ 1,928,181		$ 36,486