Accrued Liabilities (Accrued Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2023		Sep. 30, 2022		Sep. 30, 2021	Sep. 30, 2020
Accrued Liabilities, Current [Abstract]
Salaries and other member benefits	$ 146,713		$ 75,665
Product warranties and related liabilities	18,162	[1]	40,042	[1]	$ 17,481	$ 18,972
Interest payable	13,611		13,481
Accrued retirement benefits	2,822		2,779
Net current contract liabilities	33,748		30,663
Current portion of accrued restructuring charges			1,083
Taxes, other than income	13,436		21,159
Other	34,124		21,411
Accrued liabilities	$ 262,616		$ 206,283

[1] In fiscal year 2022, product warranties and related liabilities include estimates related to product liabilities expected to be fully recoverable from insurance.