Summary of Significant Accounting Policies Income and Comprehensive Income (Loss) (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
Consolidated Statement of Income and Comprehensive Income (Loss)
Provision for income taxes									$ 13,087	$ 10,145	$ 47,448
Net income	$ (5,974)	$ 33,878	$ 10,609	$ 35,906	$ (141,140)	$ 33,267	$ 9,900	$ 53,821	74,418	(44,152)	136,910
Foreign currency translation adjustment, net of taxes of $(2,970), $1,603 and $958, respectively									(74,418)	(17,861)	905
Foreign currency translation adjustment, tax expense (benefit)									(2,970)	1,603	958
Total other comprehensive (loss) income, net of tax									(73,697)	(14,681)	5,310
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									721	(58,833)	142,220
As Reported
Consolidated Statement of Income and Comprehensive Income (Loss)
Provision for income taxes									13,087	10,145	54,878
Net income									74,418	(44,152)	129,480
Foreign currency translation adjustment, net of taxes of $(2,970), $1,603 and $958, respectively									(81,220)	(18,799)	605
Total other comprehensive (loss) income, net of tax									(80,499)	(15,619)	5,010
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									(6,081)	(59,771)	134,490
Adjustment
Consolidated Statement of Income and Comprehensive Income (Loss)
Provision for income taxes											(7,430)
Net income			$ 2,647	$ 2,284							7,430
Foreign currency translation adjustment, net of taxes of $(2,970), $1,603 and $958, respectively									6,802	938	300
Total other comprehensive (loss) income, net of tax									6,802	938	300
Comprehensive Income (Loss), Net of Tax, Attributable to Parent									$ 6,802	$ 938	$ 7,730