CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (USD $) In Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Loss
Beginning Balance at Sep. 30, 2010	$ 71,598	$ 127	$ 88,399	$ (16,348)	$ (580)
Beginning Balance, shares at Sep. 30, 2010		12,691
Net income	22,988			22,988
Change in fair value of interest rate swap, net of tax	490				490
Foreign currency translation adjustments	(18)				(18)
Cash dividends	(6,901)			(6,901)
Stock-based compensation	2,344	1	2,343
Stock-based compensation, shares		117
Exercise of stock options, net	2,285	5	2,280
Exercise of stock options, shares		547
Excess tax benefit (shortfall) from stock option exercises and restricted stock vesting	2,695		2,695
Repurchase and retirement of common stock	(2,786)	(1)	(2,785)
Repurchase and retirement of common stock, shares		(129)
Ending Balance at Sep. 30, 2011	92,695	132	92,932	(261)	(108)
Ending Balance, shares at Sep. 30, 2011		13,226
Net income	19,372			19,372
Change in fair value of interest rate swap, net of tax	90				90
Foreign currency translation adjustments	(16)				(16)
Cash dividends	(9,325)			(9,325)
Stock-based compensation	2,357	1	2,356
Stock-based compensation, shares		91
Exercise of stock options, net	107	1	106
Exercise of stock options, shares		84
Excess tax benefit (shortfall) from stock option exercises and restricted stock vesting	289		289
Repurchase and retirement of common stock	(597)		(597)
Repurchase and retirement of common stock, shares		(31)
Ending Balance at Sep. 30, 2012	104,972	134	95,086	9,786	(34)
Ending Balance, shares at Sep. 30, 2012		13,370
Net income	23,943			23,943
Foreign currency translation adjustments	(33)				(33)
Cash dividends	(9,799)			(9,799)
Stock-based compensation	2,771	1	2,770
Stock-based compensation, shares		97
Exercise of stock options, net	744	1	743
Exercise of stock options, shares		123
Excess tax benefit (shortfall) from stock option exercises and restricted stock vesting	760		760
Repurchase and retirement of common stock	(725)		(725)
Repurchase and retirement of common stock, shares		(34)
Ending Balance at Sep. 30, 2013	$ 122,633	$ 136	$ 98,634	$ 23,930	$ (67)
Ending Balance, shares at Sep. 30, 2013		13,556