Business Segment Information - Schedule Of Depreciation And Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Depreciation and Amortization	$ 42,049	$ 41,338	$ 35,995
A&D
Depreciation and Amortization	10,400	9,400	8,300
USG
Depreciation and Amortization	13,500	14,400	11,300
Test
Depreciation and Amortization	5,200	5,000	5,100
Corporate, Non-Segment [Member]
Depreciation and Amortization	$ 12,900	$ 12,500	$ 11,300