v3.25.4
Segments Information - Additional Information (Details)
$ in Thousands
12 Months Ended
Dec. 31, 2025
USD ($)
Segment
Dec. 31, 2024
USD ($)
Dec. 31, 2023
USD ($)
Segment Reporting Information [Line Items]      
Number of reportable segments | Segment 2    
Segment Reporting, CODM, Individual Title and Position or Group Name [Extensible Enumeration] srt:ChiefExecutiveOfficerMember    
Segment Reporting, Expense Information Used by CODM, Description The CODM evaluates segment operating performance using segment Revenue, segment direct cost of contracts, segment Selling, General and Administrative expense and segment Adjusted EBITDA attributable to Parsons Corporation.    
Segment Reporting, CODM, Profit (Loss) Measure, How Used, Description Adjusted EBITDA is the measure of our operating performance used by the CODM to assess our segments’ financial performance. The CODM uses Adjusted EBITDA for business planning purposes, including to manage our segments against internal projected results of operations and measure the performance of our segments generally    
Revenues $ 6,364,245 $ 6,750,576 $ 5,442,749
Property and Equipment, net 151,061 111,575 98,957
United States      
Segment Reporting Information [Line Items]      
Revenues 4,700,000 5,200,000 4,100,000
Property and Equipment, net $ 130,500 $ 94,000 $ 83,900