Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income including noncontrolling interests	$ 14,371	$ 13,386
Other comprehensive income (loss), net of tax
Foreign currency translation adjustment, net of tax	(8,800)	2,549
Pension adjustments, net of tax	(61)	9
Comprehensive income including noncontrolling interests, net of tax	5,510	15,944
Comprehensive income attributable to noncontrolling interests, net of tax	(1,390)	(3,645)
Comprehensive income attributable to Parsons Corporation, net of tax	$ 4,120	$ 12,299