CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Income/(Loss)
Beginning balance (in shares) at Sep. 30, 2020		12,422,000
Beginning balance, Treasury stock (in shares) at Sep. 30, 2020					(806,000)
Beginning balance at Sep. 30, 2020	$ 306,626	$ 124	$ 61,998	$ 294,016	$ (24,999)	$ (24,513)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	631			631
Foreign currency translation adjustments	4,253					4,253
Stock-based compensation (in shares)		76,000
Stock-based compensation	2,583	$ 1	2,582
Shares withheld in lieu of employee tax withholding	(632)		(632)
Dividends	(12,142)			(12,142)
Gain (loss) on cash flow commodity hedge	0
Postretirement benefit adjustment, net of tax	(96)					(96)
Ending balance (in shares) at Sep. 30, 2021		12,498,000
Ending balance, Treasury stock (in shares) at Sep. 30, 2021					(806,000)
Ending balance at Sep. 30, 2021	301,223	$ 125	63,948	282,505	$ (24,999)	(20,356)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	13,737			13,737
Foreign currency translation adjustments	(8,689)					(8,689)
Stock-based compensation (in shares)		90,000
Stock-based compensation	4,090	$ 1	4,089
Shares withheld in lieu of employee tax withholding	(675)		(675)
Dividends	(12,527)		77	(12,604)
Gain (loss) on cash flow commodity hedge	(325)					(325)
Postretirement benefit adjustment, net of tax	$ 372					372
Ending balance (in shares) at Sep. 30, 2022	12,588,011	12,588,000
Ending balance, Treasury stock (in shares) at Sep. 30, 2022	(806,018)				(806,000)
Ending balance at Sep. 30, 2022	$ 297,206	$ 126	67,439	283,638	$ (24,999)	(28,998)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	54,525			54,525
Foreign currency translation adjustments	1,915					1,915
Stock-based compensation (in shares)		80,000
Stock-based compensation	4,599	$ 1	4,598
Shares withheld in lieu of employee tax withholding	(652)		(652)
Dividends	(12,741)		141	(12,882)
Gain (loss) on cash flow commodity hedge	325					325
Postretirement benefit adjustment, net of tax	$ (151)					(151)
Ending balance (in shares) at Sep. 30, 2023	12,668,001	12,668,000
Ending balance, Treasury stock (in shares) at Sep. 30, 2023	(806,018)				(806,000)
Ending balance at Sep. 30, 2023	$ 345,026	$ 127	$ 71,526	$ 325,281	$ (24,999)	$ (26,909)