Consolidated Statements of Stockholders' Equity and Comprehensive Income (Unaudited) (USD $)	Total	Common Stock	Additional Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Loss	Comprehensive Income
Beginning Balance at Sep. 30, 2010	$ 71,598,000	$ 127,000	$ 88,399,000	$ (16,348,000)	$ (580,000)
Beginning Balance (in shares) at Sep. 30, 2010		12,691,000
Net income	20,301,000			20,301,000		20,301,000
Change in fair value of interest rate swap, net of tax	394,000				394,000	394,000
Comprehensive income						20,695,000
Cash dividends	(4,587,000)			(4,587,000)
Stock-based compensation	1,767,000	1,000	1,766,000
Stock-based compensation (in shares)		120,000
Exercise of stock options, net	2,280,000	5,000	2,275,000
Exercise of stock options, net (in shares)	368,800	546,000
Excess tax benefit from stock option exercises and restricted stock vesting	2,926,000		2,926,000
Repurchase and retirement of common stock	(2,787,000)	(1,000)	(2,786,000)
Repurchase and retirement of common stock (in shares)		(129,000)
Ending Balance at Jun. 30, 2011	91,892,000	132,000	92,580,000	(634,000)	(186,000)
Ending Balance (in shares) at Jun. 30, 2011		13,228,000
Beginning Balance at Sep. 30, 2011	92,695,000	132,000	92,932,000	(261,000)	(108,000)
Beginning Balance (in shares) at Sep. 30, 2011		13,226,000
Net income	14,183,000			14,183,000		14,183,000
Change in fair value of interest rate swap, net of tax	90,000				90,000	90,000
Foreign currency translation adjustment	(30,000)				(30,000)	(30,000)
Comprehensive income						14,243,000
Cash dividends	6,988,000			6,988,000
Stock-based compensation	1,769,000	1,000	1,768,000
Stock-based compensation (in shares)		92,000
Exercise of stock options, net	99,000	1,000	98,000
Exercise of stock options, net (in shares)	119,600	83,000
Excess tax benefit from stock option exercises and restricted stock vesting	270,000		270,000
Repurchase and retirement of common stock	(593,000)		(593,000)
Repurchase and retirement of common stock (in shares)		(31,000)
Ending Balance at Jun. 30, 2012	$ 101,495,000	$ 134,000	$ 94,475,000	$ 6,934,000	$ (48,000)
Ending Balance (in shares) at Jun. 30, 2012		13,370,000