Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - Recurring [Member] - USD ($) $ in Thousands	Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2014
Financial assets that are measured at fair value on a recurring basis
Marketable equity securities			$ 2,641
Holding period adjustment	$ 47
Contingent consideration	(2,836)	$ (3,758)	(4,383)
Net financial assets (liabilities)	5,651	(2,606)	(1,742)
Foreign currency forward [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative assets	8,440	1,152
Convertible notes hedges [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative assets	23,160	36,994	46,454
Convertible notes embedded derivative [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative liability	(23,160)	(36,994)	(46,454)
Level 1 [Member]
Financial assets that are measured at fair value on a recurring basis
Marketable equity securities			2,641
Holding period adjustment	0
Contingent consideration	0	0	0
Net financial assets (liabilities)	0	0	2,641
Level 1 [Member] | Foreign currency forward [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative assets	0	0
Level 1 [Member] | Convertible notes hedges [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative assets	0	0	0
Level 1 [Member] | Convertible notes embedded derivative [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative liability	0	0	0
Level 2 [Member]
Financial assets that are measured at fair value on a recurring basis
Marketable equity securities			0
Holding period adjustment	47
Contingent consideration	0	0	0
Net financial assets (liabilities)	8,487	1,152	0
Level 2 [Member] | Foreign currency forward [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative assets	8,440	1,152
Level 2 [Member] | Convertible notes hedges [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative assets	23,160	36,994	46,454
Level 2 [Member] | Convertible notes embedded derivative [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative liability	(23,160)	(36,994)	(46,454)
Level 3 [Member]
Financial assets that are measured at fair value on a recurring basis
Marketable equity securities			0
Holding period adjustment	0
Contingent consideration	(2,836)	(3,758)	(4,383)
Net financial assets (liabilities)	(2,836)	(3,758)	(4,383)
Level 3 [Member] | Foreign currency forward [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative assets	0	0
Level 3 [Member] | Convertible notes hedges [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative assets	0	0	0
Level 3 [Member] | Convertible notes embedded derivative [Member]
Financial assets that are measured at fair value on a recurring basis
Derivative liability	$ 0	$ 0	$ 0