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)
Balance at Sep. 30, 2015	$ 333,262	$ 121	$ 48,507	$ 328,294	$ (21,259)	$ (22,401)
Balance, shares at Sep. 30, 2015		12,100			(670)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	15,510			15,510
Foreign currency translation adjustments	(928)					(928)
Stock-based compensation	4,883		4,883
Stock-based compensation, shares		81
Excess tax benefit from share-based compensation	(387)		(387)
Shares withheld in lieu of employee tax withholding	(1,000)		(1,000)
Issuance of restricted stock	1	$ 1
Issuance of restricted stock, shares		18
Purchase of treasury shares	(3,740)				$ (3,740)
Purchase of treasury shares, shares					(136)
Dividends paid	(11,845)			(11,845)
Postretirement benefit adjustment, net of tax	(439)					(439)
Balance at Sep. 30, 2016	335,317	$ 122	52,003	331,959	$ (24,999)	(23,768)
Balance, shares at Sep. 30, 2016		12,199			(806)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(9,486)			(9,486)
Foreign currency translation adjustments	4,822					4,822
Stock-based compensation	2,724		2,724
Stock-based compensation, shares		18
Shares withheld in lieu of employee tax withholding	(398)		(398)
Issuance of restricted stock	0	$ 0
Issuance of restricted stock, shares		17
Dividends paid	(11,875)			(11,875)
Postretirement benefit adjustment, net of tax	192					192
Balance at Sep. 30, 2017	321,296	$ 122	54,329	310,598	$ (24,999)	(18,754)
Balance, shares at Sep. 30, 2017		12,234			(806)
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	3,152		3,152
Stock-based compensation, shares		32
Shares withheld in lieu of employee tax withholding	(712)		(712)
Issuance of restricted stock	1	$ 1
Issuance of restricted stock, shares		15
Dividends paid	(11,916)			(11,916)
Postretirement benefit adjustment, net of tax	75					75
Balance at Sep. 30, 2018	$ 301,644	$ 123	$ 56,769	$ 291,530	$ (24,999)	$ (21,779)
Balance, shares at Sep. 30, 2018		12,281			(806)