Quarterly report [Sections 13 or 15(d)]

Revenue Recognition - Disaggregation of Revenue (Details)

v3.25.1
Revenue Recognition - Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Mar. 31, 2025
Mar. 31, 2024
Disaggregation of Revenue [Line Items]        
Revenue $ 1,361,786 $ 1,348,357 $ 2,764,461 $ 2,675,398
New York state government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 155,949 $ 166,952 $ 317,644 $ 327,486
New York state government agencies | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 11.50% 12.40% 11.50% 12.20%
Other U.S. state government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 287,184 $ 316,195 $ 578,251 $ 642,604
Other U.S. state government agencies | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 21.10% 23.50% 20.90% 24.00%
Total U.S. state government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 443,133 $ 483,147 $ 895,895 $ 970,090
U.S. federal government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 759,583 $ 685,939 $ 1,524,020 $ 1,348,885
U.S. federal government agencies | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 55.80% 50.90% 55.10% 50.40%
International government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 138,724 $ 156,796 $ 305,590 $ 312,408
International government agencies | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 10.20% 11.60% 11.10% 11.70%
Other, including local municipalities and commercial customers        
Disaggregation of Revenue [Line Items]        
Revenue $ 20,346 $ 22,475 $ 38,956 $ 44,015
Other, including local municipalities and commercial customers | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 1.50% 1.70% 1.40% 1.60%
Performance-based        
Disaggregation of Revenue [Line Items]        
Revenue $ 714,406 $ 738,888 $ 1,432,177 $ 1,443,599
Performance-based | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 52.50% 54.80% 51.80% 54.00%
Cost-plus        
Disaggregation of Revenue [Line Items]        
Revenue $ 334,499 $ 334,498 $ 718,926 $ 676,513
Cost-plus | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 24.60% 24.80% 26.00% 25.30%
Fixed price        
Disaggregation of Revenue [Line Items]        
Revenue $ 185,009 $ 166,816 $ 359,688 $ 343,493
Fixed price | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 13.60% 12.40% 13.00% 12.80%
Time and materials        
Disaggregation of Revenue [Line Items]        
Revenue $ 127,872 $ 108,155 $ 253,670 $ 211,793
Time and materials | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 9.40% 8.00% 9.20% 7.90%
Program Operations        
Disaggregation of Revenue [Line Items]        
Revenue $ 690,772 $ 665,050 $ 1,418,739 $ 1,352,420
Program Operations | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 50.70% 49.30% 51.30% 50.60%
Clinical Services        
Disaggregation of Revenue [Line Items]        
Revenue $ 503,963 $ 466,623 $ 975,489 $ 894,992
Clinical Services | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 37.00% 34.60% 35.30% 33.50%
Employment & Other        
Disaggregation of Revenue [Line Items]        
Revenue $ 78,989 $ 116,072 $ 192,607 $ 234,360
Employment & Other | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 5.80% 8.60% 7.00% 8.80%
Technology Solutions        
Disaggregation of Revenue [Line Items]        
Revenue $ 88,062 $ 100,612 $ 177,626 $ 193,626
Technology Solutions | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 6.50% 7.50% 6.40% 7.20%