Fair Value - Estimated Fair Value of Financial Instruments (Details) (Fair Value, Measurements, Recurring, USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Sep. 30, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative, Fair Value, Net	$ 8,006	$ 4,492
Designated as Hedging Instrument | Prepaid expenses, deferred costs and other current assets | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative Assets	8,653	3,930
Designated as Hedging Instrument | Deferred costs and other assets | Foreign Exchange Forward
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative Assets	0	1,125
Designated as Hedging Instrument | Deferred costs and other assets | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative Assets	0	275
Designated as Hedging Instrument | Accrued Liabilities | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative Liability, Fair Value, Gross Liability	$ (647)	$ (838)