Summary of Significant Accounting Policies (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Current and deferred income tax expenses
Income (loss) before income taxes	$ (22,434)	$ (30,784)	$ 53,022	$ 90,934
Current tax expense (benefit)	(1,372)	(194)	7,741	14,427
Deferred tax expense (benefit)	(9,273)	(12,393)	13,657	25,465
Total tax expense (benefit)	$ (10,645)	$ (12,587)	$ 21,398	$ 39,892