Long-term Debt (Details 4) (USD $)	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2011 2.50% Convertible senior subordinated notes due February 2014	Dec. 31, 2012 2.50% Convertible senior subordinated notes due February 2014	Sep. 30, 2012 2.50% Convertible senior subordinated notes due February 2014
Long-term debt
Interest rate on secured notes (as a percent)			2.50%	2.50%	2.50%
Repurchase and cancellation of convertible senior subordinated notes			$ 7,500,000
Cash consideration paid for cancelation of convertible senior subordinated notes			5,500,000
Gain on extinguishment of debt	0	2,025,000	2,000,000
Write-off of unamortized balances of debt discount and debt issue costs			$ 900,000