CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Paid in Capital	Accumulated Deficit	Accumulated Other Comprehensive Loss
Stockholders' equity (shares) at Sep. 30, 2012		24,602,000
Stockholders' equity at Sep. 30, 2012	$ 262,247	$ 25	$ 833,994	$ (571,772)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(33,868)			(33,868)
Change in unrealized loss related to available-for-sale securities	0
Total comprehensive income	(33,868)
Tender Offer of Mandatory Convertible & TEU, Conversion of Mandatory Convertible Notes, & Conversion of TEU (debt to stock conversion) (shares)		566,000
Tender Offer of Mandatory Convertible & TEU, Conversion of Mandatory Convertible Notes, & Conversion of TEU (debt to stock conversion)	9,402	$ 0	9,402
Amortization of nonvested stock awards	2,858		2,858
Exercises of stock options (shares)		1,000
Exercises of stock options	$ 7		7
Shares Paid for Tax Withholding for Share Based Compensation	6,147	0
Tax deficiency from stock transactions	$ (36)	$ 0	(36)	0	$ 0
Shares issued under employee stock plans, net (shares)		83,000
Shares issued under employee stock plans, net	68	$ 0	68
Common stock issued (shares)		0
Common stock issued	(7)	$ 0	(7)
Common stock redeemed (shares)		(6,000)
Common stock redeemed	(121)		(121)
Stockholders' equity (shares) at Sep. 30, 2013		25,246,000
Stockholders' equity at Sep. 30, 2013	240,550	$ 25	846,165	(605,640)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	34,383
Change in unrealized loss related to available-for-sale securities	(1,276)				(1,276)
Total comprehensive income	33,107
Tender Offer of Mandatory Convertible & TEU, Conversion of Mandatory Convertible Notes, & Conversion of TEU (debt to stock conversion) (shares)		1,368,000
Tender Offer of Mandatory Convertible & TEU, Conversion of Mandatory Convertible Notes, & Conversion of TEU (debt to stock conversion)	2,484	$ 2	2,482
Amortization of nonvested stock awards	2,587		2,587
Exercises of stock options (shares)		3,000
Exercises of stock options	$ 39		39
Shares Paid for Tax Withholding for Share Based Compensation	23,602
Tax deficiency from stock transactions	$ 698		698
Shares issued under employee stock plans, net (shares)		596,000
Shares issued under employee stock plans, net	103	$ 0	103
Forfeiture of restricted stock (shares)		(16,000)
Common stock redeemed (shares)		(24,000)
Common stock redeemed	(450)		(450)
Stockholders' equity (shares) at Sep. 30, 2014		27,173,000
Stockholders' equity at Sep. 30, 2014	279,118	$ 27	851,624	(571,257)	(1,276)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	344,094			344,094
Change in unrealized loss related to available-for-sale securities	1,276				1,276
Total comprehensive income	345,370
Tender Offer of Mandatory Convertible & TEU, Conversion of Mandatory Convertible Notes, & Conversion of TEU (debt to stock conversion) (shares)		5,222,000
Tender Offer of Mandatory Convertible & TEU, Conversion of Mandatory Convertible Notes, & Conversion of TEU (debt to stock conversion)	1	$ 5	(4)
Amortization of nonvested stock awards	6,135		6,135
Exercises of stock options (shares)		1,000
Exercises of stock options	$ 14		14
Shares Paid for Tax Withholding for Share Based Compensation	10,302
Tax deficiency from stock transactions	$ (22)		(22)
Shares issued under employee stock plans, net (shares)		410,000
Shares issued under employee stock plans, net	0	$ 0	0
Forfeiture of restricted stock (shares)		(135,000)
Common stock redeemed (shares)		(10,000)
Common stock redeemed	(192)		(192)
Other activity	(1)	$ 1	(2)
Stockholders' equity (shares) at Sep. 30, 2015		32,661,000
Stockholders' equity at Sep. 30, 2015	$ 630,423	$ 33	$ 857,553	$ (227,163)	$ 0