Revenue Recognition - Disaggregation of Revenue (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Disaggregation Of Revenue [Line Items]
Revenue from clients	$ 1,872,851	$ 2,019,787	$ 1,963,238
Time-and-Materials
Disaggregation Of Revenue [Line Items]
Revenue from clients	802,013	855,533	811,911
Fixed-Price
Disaggregation Of Revenue [Line Items]
Revenue from clients	932,659	932,353	886,200
Cost-Based
Disaggregation Of Revenue [Line Items]
Revenue from clients	138,179	231,901	265,127
U.S. Federal Government
Disaggregation Of Revenue [Line Items]
Revenue from clients	809,073	1,088,607	1,084,047
U.S. State and Local Government
Disaggregation Of Revenue [Line Items]
Revenue from clients	322,956	316,017	309,516
International Government
Disaggregation Of Revenue [Line Items]
Revenue from clients	119,131	110,680	103,446
Total Government
Disaggregation Of Revenue [Line Items]
Revenue from clients	1,251,160	1,515,304	1,497,009
Commercial
Disaggregation Of Revenue [Line Items]
Revenue from clients	621,691	504,483	466,229
Energy, Environment, Infrastructure, and Disaster Recovery
Disaggregation Of Revenue [Line Items]
Revenue from clients	979,137	934,399	805,942
Health and Social Programs
Disaggregation Of Revenue [Line Items]
Revenue from clients	620,731	765,139	814,789
Security and Other Civilian & Commercial
Disaggregation Of Revenue [Line Items]
Revenue from clients	$ 272,983	$ 320,249	$ 342,507