Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Balance at beginning of period	$ (29,203)	$ (13,584)	$ (18,594)
Other comprehensive income (loss) before reclassifications	(81,658)	(20,965)	(2,894)
Balance at end of period	(109,702)	(29,203)	(13,584)
(Increase) decrease in deferred tax liability relating to other comprehensive income (loss)	(6,327)	(7,722)	(240)
Reclassifications out of accumulated other comprehensive income (loss)
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Amount reclassified from accumulated other comprehensive income (loss)	1,159	5,346	7,904
Foreign currency translation adjustment
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Balance at beginning of period	(28,482)	(9,683)	(10,288)
Other comprehensive income (loss) before reclassifications	(81,220)	(18,799)	605
Balance at end of period	(109,702)	(28,482)	(9,683)
Gains and losses on cash flow hedges
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Balance at beginning of period	(721)	(3,901)	(8,306)
Other comprehensive income (loss) before reclassifications	(438)	(2,166)	(3,499)
Balance at end of period		(721)	(3,901)
Gains and losses on cash flow hedges | Reclassifications out of accumulated other comprehensive income (loss)
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Amount reclassified from accumulated other comprehensive income (loss)	$ 1,159	$ 5,346	$ 7,904