Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Balance, beginning of period	$ 1,456,487
Other comprehensive income (loss)	(18,746)	$ (26,109)
Less: Foreign currency translation adjustment attributable to non-controlling interest	(574)
Balance, end of period	1,408,955
Accumulated Other Comprehensive Income (Loss)
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Balance, beginning of period	(102,779)	(29,082)
Other comprehensive income (loss)	(18,746)
Other comprehensive income (loss) before reclassifications		(27,268)
Less: Foreign currency translation adjustment attributable to non-controlling interest	574
Balance, end of period	(120,951)	(55,191)
Accumulated Other Comprehensive Income (Loss) | Reclassifications out of accumulated other comprehensive income (loss)
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Amounts reclassified from accumulated other comprehensive income (loss) (2)		1,159
Foreign currency translation adjustment
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Balance, beginning of period	(102,779)	(28,361)
Other comprehensive income (loss)	(18,746)
Other comprehensive income (loss) before reclassifications		(26,830)
Less: Foreign currency translation adjustment attributable to non-controlling interest	574
Balance, end of period	$ (120,951)	(55,191)
Gains and losses on cash flow hedges
Additions to and reclassifications out of accumulated other comprehensive income (loss)
Balance, beginning of period		(721)
Other comprehensive income (loss) before reclassifications		(438)
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)
Amounts reclassified from accumulated other comprehensive income (loss) (2)		$ 1,159