Income Taxes - Deferred Taxes (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Deferred tax assets:
Pension and postretirement benefits	$ 16,802	$ 22,318
Inventories	3,225	1,498
Accrued compensation and benefits	2,096	2,034
Accrued expenses and other	2,600	3,376
Tax attributes	5,625	11,638
Other assets	250	299
Valuation allowance	(4,695)	(3,891)
Total deferred tax assets	28,299	40,248
Deferred tax liabilities:
Property, plant and equipment, net	(24,081)	(25,669)
Intangible and other	(1,414)	(1,296)
Other liabilities	(227)	(345)
Total deferred tax liabilities	(25,722)	(27,310)
Net deferred tax assets (liabilities)	2,577	12,938
Conversion Services Arrangement
Deferred tax assets:
TIMET Agreement	$ 2,396	$ 2,976