Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Income before provision for income taxes
United States									$ (93,321)	$ (225,767)	$ 10,452
Foreign									180,826	191,760	173,906
Income (loss) before income taxes	$ (32,067)	$ 47,425	$ 16,431	$ 55,716	$ (177,856)	$ 48,028	$ 15,468	$ 80,353	87,505	(34,007)	184,358
Federal
Current									(2,037)	10,668	6,831
Deferred									(17,628)	(43,708)	10,231
State
Current									3,335	3,495	2,727
Deferred									(5,725)	(5,689)	(4,106)
Foreign
Current									42,050	44,863	40,027
Deferred									(6,908)	516	(832)
Total provision (benefit)									$ 13,087	$ 10,145	$ 54,878