Debt (Schedule of Debt Instruments) (Details) (USD $)	Dec. 31, 2012	Sep. 30, 2012
Debt Instruments [Abstract]
Principal amount	$ 287,500,000	$ 287,500,000
Less: note discount	(29,487,000)	(32,333,000)
Less: note issuance costs	(3,234,000)	(3,560,000)
Senior convertible notes, net	$ 254,779,000	$ 251,607,000