Consolidated Statements Of Stockholders' Equity (USD $) In Thousands	Other Comprehensive Income (Loss) [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Sep. 30, 2009		$ 115	$ 29,401	$ 219,961	$ (2,716)	$ 246,761
Balance, shares at Sep. 30, 2009		11,480
Net income (loss)	25,008			25,008		25,008
Foreign currency translation adjustments	1,467				1,467	1,467
Exercise of stock options		1	1,699			1,700
Exercise of stock options, shares		109
Stock-based compensation		1	791			792
Stock-based compensation, shares		58
Income tax benefit from stock options exercised			878			878
Amortization of restricted stock			467			467
Issuance of restricted stock			333			333
Issuance of restricted stock, shares		30
Unrealized (loss) gain on cash flow hedges, net of tax of $265 and $94 for the period ended 2010 and 2011 respectively	(206)				(206)	(206)
Postretirement benefit adjustment, net of tax of $58, $60 and $20 for the period ended 2010, 2011 and 2012 respectively	103				103	103
Total comprehensive income (loss)	26,372			25,008	1,364	26,372
Balance at Sep. 30, 2010		117	33,569	244,969	(1,352)	277,303
Balance, shares at Sep. 30, 2010		11,677
Net income (loss)	(2,715)			(2,715)		(2,715)
Foreign currency translation adjustments	(19)				(19)	(19)
Exercise of stock options			495			495
Exercise of stock options, shares		27
Stock-based compensation			(1,223)			(1,223)
Stock-based compensation, shares		20
Income tax benefit from stock options exercised			180			180
Amortization of restricted stock			280			280
Issuance of restricted stock			1,042			1,042
Issuance of restricted stock, shares		28
Unrealized (loss) gain on cash flow hedges, net of tax of $265 and $94 for the period ended 2010 and 2011 respectively	111				111	111
Postretirement benefit adjustment, net of tax of $58, $60 and $20 for the period ended 2010, 2011 and 2012 respectively	(111)				(111)	(111)
Total comprehensive income (loss)	(2,734)			(2,715)	(19)	(2,734)
Balance at Sep. 30, 2011		117	34,343	242,254	(1,371)	275,343
Balance, shares at Sep. 30, 2011		11,752
Net income (loss)	29,657			29,657		29,657
Foreign currency translation adjustments	833				833	833
Exercise of stock options		1	1,798			1,799
Exercise of stock options, shares		98
Stock-based compensation			1,004			1,004
Stock-based compensation, shares		7
Income tax benefit from stock options exercised			589			589
Amortization of restricted stock			135			135
Issuance of restricted stock		1	583			584
Issuance of restricted stock, shares		74
Retirement of stock		(15)
Postretirement benefit adjustment, net of tax of $58, $60 and $20 for the period ended 2010, 2011 and 2012 respectively	159				159	159
Total comprehensive income (loss)	30,649			29,657	992	30,649
Balance at Sep. 30, 2012		$ 119	$ 38,452	$ 271,911	$ (379)	$ 310,103
Balance, shares at Sep. 30, 2012		11,916