Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Statement of Comprehensive Income [Abstract]
Net income including noncontrolling interests	$ 85,589	$ 59,811	$ 74,196	$ 149,858
Other comprehensive income, net of tax
Foreign currency translation adjustment, net of tax	2,977	(1,929)	(1,195)	1,046
Pension adjustments, net of tax	23	(11)	(24)	6
Comprehensive income including noncontrolling interests, net of tax	88,589	57,871	72,977	150,910
Comprehensive income attributable to noncontrolling interests, net of tax	(13,641)	(12,361)	(40,443)	(33,617)
Comprehensive income attributable to Parsons Corporation, net of tax	$ 74,948	$ 45,510	$ 32,534	$ 117,293