Long-term Debt (Details 4) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Long-term debt
Gain on extinguishment of debt	$ 0	$ 35,000	$ 2,479,000
Convertible Senior Subordinated Notes 2.50 Percent Due 2014
Long-term debt
Interest rate on secured notes (as a percent)	2.50%	2.50%
Conversion rate of notes to shares	33.9236
Debt instrument convertible principal amount	1,000
Debt instrument convertible conversion price (in dollars per share)	$ 29.48
Debt instrument conversion price observation period	20 days
Debt instrument convertible if closing stock price exceeds stated common stock price per share	$ 38.32
Debt instrument convertible if stock price exceeds stated common stock price per share consecutive trading days	30 days
Number of consecutive business days immediately after any ten-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 the product of common stock trading price and number of shares of common stock issuable upon conversion below which notes are convertible	98.00%
Repurchase and cancellation of convertible senior subordinated notes			49,800,000
Write-off of unamortized balances of debt discount and debt issue costs			4,500,000
Convertible Senior Subordinated Notes 2.50 Percent Due 2014 Repurchased for Cash
Long-term debt
Cash consideration paid for cancelation of convertible senior subordinated notes		47,700,000	13,500,000
Repurchase and cancellation of convertible senior subordinated notes		47,400,000	16,000,000
Write-off of unamortized balances of debt discount and debt issue costs		2,400,000	1,600,000
Gain on extinguishment of debt			2,500,000
Convertible Senior Subordinated Notes 8.75 Percent Due 2016
Long-term debt
Interest rate on secured notes (as a percent)	8.75%	8.75%	8.75%
Additional borrowings			49,800,000
Cash consideration paid for cancelation of convertible senior subordinated notes			600,000
Convertible Senior Subordinated Notes 8.75 Percent Due 2016 | Board of Directors Chairman
Long-term debt
Convertible senior subordinated notes, net of applicable discounts			1,150,000
Former Convertible Senior Subordinated Notes
Long-term debt
Write-off of unamortized balances of debt discount and debt issue costs			$ 2,500,000