Debt (Schedule Of Note Related Interest Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
2015 Convertible Senior Notes
Contractual interest expense	$ 7,188	$ 7,188	$ 7,188
Amortization of notes issuance costs	1,412	1,266	1,212
Accretion of notes discount	11,834	10,880	10,121
Total interest expense recognized	20,434	19,334	18,521
Effective interest reate of the liability component	7.73%	7.73%	7.73%
2018 Convertible Senior Notes
Contractual interest expense	787	0	0
Amortization of notes issuance costs	625	0	0
Accretion of notes discount	5,784	0	0
Total interest expense recognized	$ 7,196	$ 0	$ 0
Effective interest reate of the liability component	5.75%	0.00%	0.00%