Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income Statement [Abstract]
Revenue	$ 5,442,749	$ 4,195,272	$ 3,660,771
Direct cost of contracts	4,236,735	3,248,550	2,807,950
Equity in (losses) earnings of unconsolidated joint ventures	(47,751)	16,347	36,862
Selling, general and administrative expenses	869,905	777,403	757,237
Operating income	288,358	185,666	132,446
Interest income	2,191	966	396
Interest expense	(31,497)	(23,185)	(17,697)
Other income (expense), net	5,001	2,775	(2,557)
Total other (expense) income	(24,305)	(19,444)	(19,858)
Income before income tax expense	264,053	166,222	112,588
Income tax expense	(56,138)	(39,657)	(23,636)
Net income including noncontrolling interests	207,915	126,565	88,952
Net income attributable to noncontrolling interests	(46,766)	(29,901)	(24,880)
Net income attributable to Parsons Corporation	$ 161,149	$ 96,664	$ 64,072
Earnings per share:
Basic earnings per share	$ 1.53	$ 0.93	$ 0.62
Diluted earnings per share	$ 1.42	$ 0.87	$ 0.59