v3.25.4
ENTITY WIDE DISCLOSURES - Narrative (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2025
Dec. 31, 2024
Dec. 31, 2023
Segment Reporting Information [Line Items]      
Direct operating costs $ 1,769,616 $ 1,452,749 $ 1,361,337
Selling, general and administrative 197,559 180,184 161,352
Depreciation 27,178 27,808 24,129
Amortization 946 1,443 2,199
Total operating expenses 1,995,299 1,662,184 1,549,017
Operating Income (Loss) 534,935 446,870 336,825
Miscellaneous (expense) income, net (5,338) 4,056 (655)
Interest income (expense), net 12,780 24,996 (488)
Nonoperating Income (Expense) 7,442 29,052 (1,143)
Income before income taxes 542,377 475,922 335,682
Income tax provision 91,254 71,536 52,872
Net income 451,123 404,386 282,810
Total revenue 2,530,234 2,109,054 1,885,842
Reimbursed out-of-pocket expenses      
Segment Reporting Information [Line Items]      
Direct operating costs 1,037,488 770,654 723,088
Direct Costs      
Segment Reporting Information [Line Items]      
Direct operating costs $ 732,128 $ 682,095 $ 638,249
United States | Total Revenue | Geographical Locations      
Product And Services Information [Line Items]      
Percentage of total revenue to consolidated total revenue 99.00% 98.00% 98.00%
Operating Segments | Reportable Segment      
Segment Reporting Information [Line Items]      
Direct operating costs $ 1,769,616 $ 1,452,749 $ 1,361,337
Selling, general and administrative 197,559 180,184 161,352
Depreciation 27,178 27,808 24,129
Amortization 946 1,443 2,199
Total operating expenses 1,995,299 1,662,184 1,549,017
Operating Income (Loss) 534,935 446,870 336,825
Miscellaneous (expense) income, net (5,338) 4,056 (655)
Interest income (expense), net 12,780 24,996 (488)
Nonoperating Income (Expense) 7,442 29,052 (1,143)
Income before income taxes 542,377 475,922 335,682
Income tax provision 91,254 71,536 52,872
Net income 451,123 404,386 282,810
Total revenue 2,530,234 2,109,054 1,885,842
Operating Segments | Reportable Segment | Reimbursed out-of-pocket expenses      
Segment Reporting Information [Line Items]      
Direct operating costs 1,037,488 770,654 723,088
Operating Segments | Reportable Segment | Direct Costs      
Segment Reporting Information [Line Items]      
Segment Reporting, Other Segment Item, Amount 143,342 136,678 138,721
Labor and Related Expense $ 588,786 545,417 499,528
Segment Reporting, Other Segment Item, Composition, Description (a) Direct service costs, excluding depreciation and amortization - Other segment items includes costs related to inventory, leases, project subcontractors and other direct service costs.    
Adjustments and reconciling items      
Segment Reporting Information [Line Items]      
Net income $ 0 $ 0 $ 0