Significant Accounting Policies - Reclassification Out of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	$ 185	$ 37
Net loss	729	5,383
Amount reclassified from accumulated other comprehensive income (loss) | Net actuarial gain
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before taxes	1,498	844
Amount reclassified from accumulated other comprehensive income (loss) | Settlements/curtailments
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before taxes	0	60
Amount reclassified from accumulated other comprehensive income (loss) | Retirement Plan Liability Adjustment
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before taxes	1,498	904
Income tax expense	0	0
Net loss	$ 1,498	$ 904