Annual report pursuant to Section 13 and 15(d)

Revenue Recognition - Disaggregation of Revenue (Details)

v3.24.3
Revenue Recognition - Disaggregation of Revenue (Details) - USD ($)
$ in Thousands
 12 Months Ended
Sep. 30, 2024
Sep. 30, 2023
Sep. 30, 2022
Disaggregation of Revenue [Line Items]      
Revenue $ 5,306,197 $ 4,904,728 $ 4,631,018
New York state government agencies      
Disaggregation of Revenue [Line Items]      
Revenue $ 647,349 $ 525,051 $ 389,004
New York state government agencies | Revenue Benchmark | Customer Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 12.20% 10.70% 8.40%
Other U.S. state government agencies      
Disaggregation of Revenue [Line Items]      
Revenue $ 1,255,181 $ 1,275,763 $ 1,216,453
Other U.S. state government agencies | Revenue Benchmark | Customer Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 23.70% 26.00% 26.30%
Total U.S. state government agencies      
Disaggregation of Revenue [Line Items]      
Revenue $ 1,902,530 $ 1,800,814 $ 1,605,457
United States federal government agencies      
Disaggregation of Revenue [Line Items]      
Revenue $ 2,674,014 $ 2,344,863 $ 2,189,303
United States federal government agencies | Revenue Benchmark | Customer Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 50.40% 47.80% 47.30%
International government agencies      
Disaggregation of Revenue [Line Items]      
Revenue $ 642,222 $ 663,044 $ 722,192
International government agencies | Revenue Benchmark | Customer Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 12.10% 13.50% 15.60%
Other, including local municipalities and commercial customers      
Disaggregation of Revenue [Line Items]      
Revenue $ 87,431 $ 96,007 $ 114,066
Other, including local municipalities and commercial customers | Revenue Benchmark | Customer Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 1.60% 2.00% 2.50%
Performance-based      
Disaggregation of Revenue [Line Items]      
Revenue $ 2,939,536 $ 2,425,597 $ 2,091,608
Performance-based | Revenue Benchmark | Contract Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 55.40% 49.50% 45.20%
Cost-plus      
Disaggregation of Revenue [Line Items]      
Revenue $ 1,247,202 $ 1,238,574 $ 1,248,759
Cost-plus | Revenue Benchmark | Contract Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 23.50% 25.30% 27.00%
Fixed price      
Disaggregation of Revenue [Line Items]      
Revenue $ 686,555 $ 717,167 $ 627,402
Fixed price | Revenue Benchmark | Contract Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 12.90% 14.60% 13.50%
Time and materials      
Disaggregation of Revenue [Line Items]      
Revenue $ 432,904 $ 523,390 $ 663,249
Time and materials | Revenue Benchmark | Contract Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 8.20% 10.70% 14.30%
Program Operations      
Disaggregation of Revenue [Line Items]      
Revenue $ 2,570,494 $ 2,500,678 $ 2,502,620
Program Operations | Revenue Benchmark | Contract Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 48.40% 51.00% 54.00%
Clinical Services      
Disaggregation of Revenue [Line Items]      
Revenue $ 1,891,292 $ 1,486,040 $ 1,176,081
Clinical Services | Revenue Benchmark | Contract Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 35.60% 30.30% 25.40%
Employment & Other      
Disaggregation of Revenue [Line Items]      
Revenue $ 469,304 $ 520,981 $ 551,755
Employment & Other | Revenue Benchmark | Contract Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 8.80% 10.60% 11.90%
Technology Solutions      
Disaggregation of Revenue [Line Items]      
Revenue $ 375,107 $ 397,029 $ 400,562
Technology Solutions | Revenue Benchmark | Contract Concentration Risk      
Disaggregation of Revenue [Line Items]      
Revenue in % 7.10% 8.10% 8.60%