Quarterly report [Sections 13 or 15(d)]

Revenue Recognition - Disaggregation of Revenue (Details)

v3.25.2
Revenue Recognition - Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Disaggregation of Revenue [Line Items]        
Revenue $ 1,348,400 $ 1,314,929 $ 4,112,861 $ 3,990,327
New York state government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 148,408 $ 159,927 $ 466,053 $ 487,413
New York state government agencies | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 11.00% 12.20% 11.30% 12.20%
Other U.S. state government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 291,312 $ 310,374 $ 869,561 $ 952,978
Other U.S. state government agencies | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 21.60% 23.60% 21.10% 23.90%
Total U.S. state government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 439,720 $ 470,301 $ 1,335,614 $ 1,440,391
U.S. federal government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 743,058 $ 666,895 $ 2,267,078 $ 2,015,780
U.S. federal government agencies | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 55.10% 50.70% 55.10% 50.50%
International government agencies        
Disaggregation of Revenue [Line Items]        
Revenue $ 146,018 $ 156,587 $ 451,608 $ 468,995
International government agencies | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 10.80% 11.90% 11.00% 11.80%
Other, including local municipalities and commercial customers        
Disaggregation of Revenue [Line Items]        
Revenue $ 19,604 $ 21,146 $ 58,561 $ 65,161
Other, including local municipalities and commercial customers | Revenue Benchmark | Customer Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 1.50% 1.60% 1.40% 1.60%
Performance-based        
Disaggregation of Revenue [Line Items]        
Revenue $ 761,428 $ 758,942 $ 2,193,605 $ 2,202,541
Performance-based | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 56.50% 57.70% 53.30% 55.20%
Cost-plus        
Disaggregation of Revenue [Line Items]        
Revenue $ 301,385 $ 281,823 $ 1,020,311 $ 958,336
Cost-plus | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 22.40% 21.40% 24.80% 24.00%
Fixed price        
Disaggregation of Revenue [Line Items]        
Revenue $ 180,390 $ 170,787 $ 540,078 $ 514,280
Fixed price | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 13.40% 13.00% 13.10% 12.90%
Time and materials        
Disaggregation of Revenue [Line Items]        
Revenue $ 105,197 $ 103,377 $ 358,867 $ 315,170
Time and materials | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 7.80% 7.90% 8.70% 7.90%
Program Operations        
Disaggregation of Revenue [Line Items]        
Revenue $ 626,981 $ 604,614 $ 2,045,720 $ 1,957,034
Program Operations | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 46.50% 46.00% 49.70% 49.00%
Clinical Services        
Disaggregation of Revenue [Line Items]        
Revenue $ 560,360 $ 506,077 $ 1,535,849 $ 1,401,069
Clinical Services | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 41.60% 38.50% 37.30% 35.10%
Employment & Other        
Disaggregation of Revenue [Line Items]        
Revenue $ 81,906 $ 112,044 $ 274,513 $ 346,404
Employment & Other | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 6.10% 8.50% 6.70% 8.70%
Technology Solutions        
Disaggregation of Revenue [Line Items]        
Revenue $ 79,153 $ 92,194 $ 256,779 $ 285,820
Technology Solutions | Revenue Benchmark | Contract Concentration Risk        
Disaggregation of Revenue [Line Items]        
Revenue in % 5.90% 7.00% 6.20% 7.20%