CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ 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, 2017		12,234			(806)
Beginning balance at Sep. 30, 2017	$ 321,296	$ 122	$ 54,329	$ 310,598	$ (24,999)	$ (18,754)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(7,152)			(7,152)
Foreign currency translation adjustments	(3,100)					(3,100)
Stock-based compensation (in shares)		32
Stock-based compensation	3,152		3,152
Shares withheld in lieu of employee tax withholding	(712)		(712)
Issuance of restricted stock (in shares)		15
Issuance of restricted stock	1	$ 1
Dividends paid	(11,916)			(11,916)
Postretirement benefit adjustment, net of tax	75					75
Ending balance (in shares) at Sep. 30, 2018		12,281			(806)
Ending balance at Sep. 30, 2018	301,644	$ 123	56,769	291,530	$ (24,999)	(21,779)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	9,890			9,890
Foreign currency translation adjustments	(2,743)					(2,743)
Stock-based compensation (in shares)		78
Stock-based compensation	3,839	$ 1	3,838
Shares withheld in lieu of employee tax withholding	(1,454)		(1,454)
Issuance of restricted stock (in shares)		14
Issuance of restricted stock	0
Dividends paid	(11,998)			(11,998)
Postretirement benefit adjustment, net of tax	(25)					(25)
Ending balance (in shares) at Sep. 30, 2019		12,373			(806)
Ending balance at Sep. 30, 2019	299,153	$ 124	59,153	289,422	$ (24,999)	(24,547)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	16,660			16,660
Foreign currency translation adjustments	60					60
Stock-based compensation (in shares)		33
Stock-based compensation	3,474		3,474
Shares withheld in lieu of employee tax withholding	(629)		(629)
Issuance of restricted stock (in shares)		16
Issuance of restricted stock	0
Dividends paid	(12,066)			(12,066)
Postretirement benefit adjustment, net of tax	(26)					(26)
Ending balance (in shares) at Sep. 30, 2020		12,422			(806)
Ending balance at Sep. 30, 2020	$ 306,626	$ 124	$ 61,998	$ 294,016	$ (24,999)	$ (24,513)