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, 2014	$ 371,097	$ 120	$ 46,267	$ 331,213		$ (6,503)
Balance, shares at Sep. 30, 2014		12,031
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	9,439			9,439
Foreign currency translation adjustments	(16,104)					(16,104)
Stock-based compensation	3,171		3,171
Stock-based compensation, shares		53
Excess tax benefit from share-based compensation	(191)		(191)
Shares withheld in lieu of employee tax withholding	(740)		(740)
Issuance of restricted stock	1	$ 1
Issuance of restricted stock, shares		16
Purchase of treasury shares	(21,259)				$ (21,259)
Purchase of treasury shares, shares					(670)
Dividends paid	(12,358)			(12,358)
Postretirement benefit adjustment, net of tax	206					206
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
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)