Long-Term Debt (Details 4) (USD $)	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Long-term debt
Gain on extinguishment of debt	$ 35,000	$ 2,479,000	$ 0
2.50% Convertible senior subordinated notes due February 2014
Long-term debt
Interest rate on secured notes (as a percent)	2.50%	2.50%
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 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%
Hedged conversion price to common stock price per share	$ 35.00
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, net of applicable discounts	7,700,000
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
8.75% Convertible senior subordinated notes due February 2016
Long-term debt
Interest rate on secured notes (as a percent)	8.75%	8.75%
Additional borrowings		49,800,000
Cash consideration paid for cancelation of convertible senior subordinated notes		600,000
Debt instrument, extended maturity term		2 years
8.75% Convertible senior subordinated notes due February 2016 | Chairman and CEO
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	$ 5,200,000