Liabilities (Details 5) (USD $)	12 Months Ended												12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2012 16% Convertible senior subordinated notes due 2016	Sep. 30, 2011 16% Convertible senior subordinated notes due 2016	Sep. 30, 2010 16% Convertible senior subordinated notes due 2016	Sep. 30, 2009 16% Convertible senior subordinated notes due 2016	Sep. 30, 2009 16% Convertible senior subordinated notes due 2016 Exchange Notes For Stock	Sep. 30, 2012 2.50% Convertible senior subordinated notes due 2014	Sep. 30, 2009 2.50% Convertible senior subordinated notes due 2014	Sep. 30, 2007 2.50% Convertible senior subordinated notes due 2014	Sep. 30, 2011 2.50% Convertible senior subordinated notes due 2014	Sep. 30, 2012 Convertible Senior Subordinated Notes 2.50 Percent Due 2014 Exchanged For Convertible Senior Subordinated Notes 8.75 Percent	Sep. 30, 2012 Convertible Senior Subordinated Notes 2.50 Percent Due 2014 Repurchased for Cash	Sep. 30, 2009 2.875% Convertible Senior Subordinated Notes Due 2016	Sep. 30, 2009 2.875% Convertible Senior Subordinated Notes Due 2016 Exchange Notes For Notes	Sep. 30, 2012 14.75% Convertible senior subordinated notes due 2014	Sep. 30, 2011 14.75% Convertible senior subordinated notes due 2014	Sep. 30, 2009 14.75% Convertible senior subordinated notes due 2014	Sep. 30, 2012 8.75% Convertible senior subordinated notes due 2016	Sep. 30, 2012 8.75% Convertible senior subordinated notes due 2016 Chairman and CEO
Long-term debt
Convertible subordinated notes noncurrent exchanged								$ 15,000,000		$ 39,100,000						$ 63,300,000
Convertible subordinated notes noncurrent issued in exchange							63,300,000												27,400,000
Conversion rate of notes to shares										0.0339236
Debt instrument convertible principal amount										1,000
Debt instrument convertible conversion price (in dollars per share)										$ 29.48
Debt instrument convertible if converted value in excess of stated common stock price per share minimum trading days									20 days
Debt instrument convertible if closing stock price exceeds stated common stock price per share									$ 38.32
Debt instrument convertible if converted value in excess of stated common stock price per share consecutive trading days									30 days
Number of consecutive business days immediately after any five consecutive trading day period									5 days
Number of consecutive trading days before five consecutive business days during the note measurement period									10 days
Maximum percentage of common stock trading price below which notes are convertible									98.00%
Original conversion to common stock price per share											$ 29.48
Hedged conversion price to common stock price per share											$ 35.00
Interest rate on secured notes (as a percent)					16.00%		16.00%		2.50%			2.50%			2.875%			14.75%		8.75%
Additional borrowings											160,000,000									49,800,000
Cash consideration paid for cancelation of convertible senior subordinated notes														13,500,000
Cash premium paid in excess of the exchange value													600,000
Repurchase and cancellation of convertible senior subordinated notes				9,200,000	10,000,000	29,000,000							49,800,000	16,000,000	39,100,000		13,000,000	14,400,000
Write-off of unamortized balances of debt discount and debt issue costs					600,000	2,100,000							4,500,000	1,600,000			800,000	1,100,000
Debt instrument, extended maturity term																				2 years
Convertible senior subordinated notes, net of applicable discounts									55,100,000												1,150,000
Debt instrument early repayment premium		62,600,000			1,700,000	5,000,000											1,700,000	1,800,000
Gain on extinguishment of debt	$ 2,479,000	$ 0	$ 0											$ 2,500,000