Restatement of Condensed Consolidated Financial Statements (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Net income	$ 16,120	$ 29,702	$ 24,549	$ 44,016
Other comprehensive income (loss):
Foreign currency translation	3,645	(15,338)	11,862	(13,989)
Change in fair value of cash flow hedges, net of tax	(1,288)	(732)	(181)	(1,337)
Adjustment for net gains/losses realized and included in net income, net of tax	(55)	(13)	(23)	1,334
Total change in net unrealized gains/losses from cash flow hedges, net of tax	(1,343)	(745)	(204)	(3)
Total other comprehensive loss	2,302	(16,083)	11,658	(13,992)
Total comprehensive income	18,422	13,619	36,207	30,024
Previously Reported
Net income		27,210		39,729
Other comprehensive income (loss):
Foreign currency translation		(14,608)		(13,313)
Change in fair value of cash flow hedges, net of tax		(732)		(1,337)
Adjustment for net gains/losses realized and included in net income, net of tax		(13)		1,334
Total change in net unrealized gains/losses from cash flow hedges, net of tax		(745)		(3)
Total other comprehensive loss		(15,353)		(13,316)
Total comprehensive income		11,857		26,413
Adjustments
Net income		2,492		4,287
Other comprehensive income (loss):
Foreign currency translation		(730)		(676)
Total other comprehensive loss		(730)		(676)
Total comprehensive income		$ 1,762		$ 3,611