Revenues - Disaggregation of Revenues (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	$ 857,502	$ 715,440	$ 730,471
Point in time
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	427,063	330,221
Over time
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	430,439	385,219
United States
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	603,172	516,959	529,400
International
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	254,330	198,481
Commercial
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	625,753	506,929
Government
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	231,749	208,511
A&D
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	351,413	314,824	351,900
A&D | Point in time
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	144,039	136,449
A&D | Over time
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	207,374	178,375
A&D | United States
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	299,158	275,976
A&D | International
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	52,255	38,848
A&D | Commercial
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	144,305	130,217
A&D | Government
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	207,108	184,607
USG
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	278,367	202,908	191,700
USG | Point in time
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	224,502	153,163
USG | Over time
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	53,865	49,745
USG | United States
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	180,586	140,545
USG | International
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	97,781	62,363
USG | Commercial
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	272,432	199,111
USG | Government
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	5,935	3,797
Test
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	227,722	197,708	$ 186,900
Test | Point in time
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	58,522	40,609
Test | Over time
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	169,200	157,099
Test | United States
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	123,428	100,438
Test | International
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	104,294	97,270
Test | Commercial
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	209,016	177,601
Test | Government
Disaggregation of revenues
Revenue from contract with customer excluding assessed tax	$ 18,706	$ 20,107