Business Segment Information - Schedule Of Depreciation And Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Depreciation and Amortization	$ 50,523	$ 48,343	$ 42,049
Corporate
Depreciation and Amortization	18,600	19,200	12,900
Operating Segments | A&D
Depreciation and Amortization	12,600	11,100	10,400
Operating Segments | USG
Depreciation and Amortization	14,000	12,600	13,500
Operating Segments | Test
Depreciation and Amortization	$ 5,300	$ 5,400	$ 5,200