Summary of Significant Accounting Policies - Reclassification Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	$ (43)	$ (1,222)
Net (loss)	(9,640)	(743)
Amount reclassified from accumulated other comprehensive loss | Net actuarial gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before taxes	1,003	4,217
Amount reclassified from accumulated other comprehensive loss | Settlements/curtailments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before taxes	208	274
Amount reclassified from accumulated other comprehensive loss | Retirement Plan Liability Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before taxes	1,211	4,491
Income tax expense	0	0
Net (loss)	$ 1,211	$ 4,491