Investments in and Advances to Joint Ventures - Summary of Financial Information for Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Schedule Of Equity Method Investments [Line Items]
Current assets	$ 1,801,343		$ 1,719,783
Total assets	4,255,806		4,198,142
Current liabilities	1,140,071		1,108,119
Total liabilities	2,130,276		2,102,207
Total joint venture equity	2,063,879		2,043,570
Investments in and advances to unconsolidated joint ventures	107,416		107,425
Revenue	1,173,466	$ 949,069
Costs	917,188	733,900
Net income attributable to Parsons Corporation	25,553	20,667
Equity in (losses) earnings of unconsolidated joint ventures	(5,840)	5,598
Unconsolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Current assets	1,291,910		1,610,246
Noncurrent assets	493,501		491,658
Total assets	1,785,411		2,101,904
Current liabilities	848,105		1,255,297
Noncurrent liabilities	540,967		468,056
Total liabilities	1,389,072		1,723,353
Total joint venture equity	396,339		378,551
Investments in and advances to unconsolidated joint ventures	107,416		$ 107,425
Revenue	349,157	384,581
Costs	359,395	373,286
Net income attributable to Parsons Corporation	(10,238)	11,295
Unconsolidated Joint Ventures
Schedule Of Equity Method Investments [Line Items]
Equity in (losses) earnings of unconsolidated joint ventures	$ (5,840)	$ 5,598