Consolidated Statements of Stockholders' Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning balance at Sep. 30, 2008	$ 141,806	$ 901	$ 74,573	$ (107)	$ 66,439
Beginning balance, shares at Sep. 30, 2008		18,030
Components of comprehensive income (loss), net of tax:
Net (loss) income	37,550				37,550
Unrealized holding gains (losses) on available-for-sale securities arising during the period	2,123			2,123
Add reclassification for gains included in net income (loss), net of tax provision of $299, $118 and $144 in 2009, 2010 and 2011, respectively	(512)			(512)
Comprehensive income (loss)	39,161
Issuance of common stock, shares		40
Issuance of common stock	613	2	611
Common stock repurchased, shares		(624)
Common stock repurchased	(14,998)	(31)	(14,967)
Common stock options exercised, net, shares		15
Common stock options exercised, net	66	1	65
Purchase of common stock to pay employee taxes, shares		10
Purchase of common stock to pay employee taxes	(568)	1	(569)
(Reduction) excess of tax benefit from stock-based compensation plans	(366)		(366)
Stock-based compensation	6,853		6,853
Other	(195)		(195)
Ending balance at Sep. 30, 2009	172,372	874	66,005	1,504	103,989
Ending balance, shares at Sep. 30, 2009		17,471
Components of comprehensive income (loss), net of tax:
Net (loss) income	(21,089)				(21,089)
Unrealized holding gains (losses) on available-for-sale securities arising during the period	(437)			(437)
Add reclassification for gains included in net income (loss), net of tax provision of $299, $118 and $144 in 2009, 2010 and 2011, respectively	(181)			(181)
Comprehensive income (loss)	(21,707)
Issuance of common stock, shares		40
Issuance of common stock	610	2	608
Common stock repurchased, shares		(102)
Common stock repurchased	(2,032)	(6)	(2,026)
Common stock options exercised, net, shares		14
Common stock options exercised, net	282	1	281
Purchase of common stock to pay employee taxes, shares		1
Purchase of common stock to pay employee taxes	(545)		(545)
(Reduction) excess of tax benefit from stock-based compensation plans	(496)		(496)
Stock-based compensation	5,875		5,875
Ending balance at Sep. 30, 2010	154,359	871	69,702	886	82,900
Ending balance, shares at Sep. 30, 2010		17,424
Components of comprehensive income (loss), net of tax:
Net (loss) income	(18,506)				(18,506)
Unrealized holding gains (losses) on available-for-sale securities arising during the period	(804)			(804)
Add reclassification for gains included in net income (loss), net of tax provision of $299, $118 and $144 in 2009, 2010 and 2011, respectively	(235)			(235)
Comprehensive income (loss)	(19,545)
Issuance of common stock, shares		55
Issuance of common stock	574	3	571
Purchase of common stock to pay employee taxes, shares		52
Purchase of common stock to pay employee taxes	(40)	3	(43)
(Reduction) excess of tax benefit from stock-based compensation plans	8		8
Stock-based compensation	4,252		4,252
Ending balance at Sep. 30, 2011	$ 139,608	$ 877	$ 74,490	$ (153)	$ 64,394
Ending balance, shares at Sep. 30, 2011		17,531