Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Income Statement [Abstract]
Revenue	$ 6,750,576	$ 5,442,749	$ 4,195,272
Direct cost of contracts	5,344,154	4,236,735	3,248,550
Equity in (losses) earnings of unconsolidated joint ventures	(23,361)	(47,751)	16,347
Selling, general and administrative expenses	954,995	869,905	777,403
Operating income	428,066	288,358	185,666
Interest income	11,428	2,191	966
Interest expense	(51,582)	(31,497)	(23,185)
Convertible debt repurchase loss	(18,355)	0	0
Other income (expense), net	(1,906)	5,001	2,775
Total other (expense) income	(60,415)	(24,305)	(19,444)
Income before income tax expense	367,651	264,053	166,222
Income tax expense	(76,986)	(56,138)	(39,657)
Net income including noncontrolling interests	290,665	207,915	126,565
Net income attributable to noncontrolling interests	(55,612)	(46,766)	(29,901)
Net income attributable to Parsons Corporation	$ 235,053	$ 161,149	$ 96,664
Earnings per share:
Basic earnings per share	$ 2.21	$ 1.53	$ 0.93
Diluted earnings per share	$ 2.12	$ 1.42	$ 0.87