CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 35,288	$ 87,737	$ 55,918
Other comprehensive income:
Unrealized gain (loss) on pension plan obligation	(436)	735	2,876
Tax effect of unrealized gain (loss) on pension plan obligation	129	(217)	(782)
Unrealized gain (loss) on captive insurance collateral	(4,952)	(963)	916
Tax effect of unrealized gain (loss) on captive insurance collateral	1,043	203	(190)
Unrealized gain (loss) on interest rate hedge	3,607	1,575	(1,193)
Tax effect of unrealized gain (loss) on interest rate hedge	(959)	(414)	317
Total other comprehensive income (loss)	(1,568)	919	1,944
Total comprehensive income	$ 33,720	$ 88,656	$ 57,862