Fair Value of Financial Instruments (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Mar. 31, 2014
Impact on income statement of derivative instruments designated as cash flow and net investment hedging instruments
Amount of Gain or (Loss) Recognized in Accumulated OCI on Derivative (Effective Portion)	$ 9,481	$ (1,553)	$ 18,213	$ (6,489)
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)		(1,147)	(1,159)	(3,014)
Interest rate swaps | Cash Flow Hedges:
Impact on income statement of derivative instruments designated as cash flow and net investment hedging instruments
Amount of Gain or (Loss) Recognized in Accumulated OCI on Derivative (Effective Portion)		(463)	(438)	(1,245)
Amount of Gain or (Loss) Reclassified from Accumulated OCI into Income (Effective Portion)		(1,147)	(1,159)	(3,014)
Cross currency swaps | Net Investment Hedges:
Impact on income statement of derivative instruments designated as cash flow and net investment hedging instruments
Amount of Gain or (Loss) Recognized in Accumulated OCI on Derivative (Effective Portion)	$ 9,481	$ (1,090)	$ 18,651	$ (5,244)