Derivative Instruments and Hedging Activities (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015	Sep. 30, 2015	Jun. 30, 2014
Derivative [Line Items]
Proceeds from settlement of forward currency contracts				$ 3,557	$ 2,313
Not Designated as Hedging Instrument | Foreign currency forwards | Other expense
Derivative [Line Items]
Amount of unrealized gain (loss) on derivatives	$ (1,805)		$ 784	(2,918)	7,798
Receivables, prepaid expenses and other current assets | Not Designated as Hedging Instrument | Foreign currency forwards
Derivative [Line Items]
Fair value, asset of derivative instruments	7,694		2,530	7,694	2,530	$ 14,169
Other assets, net | Not Designated as Hedging Instrument | Cash Convertible Notes Hedges
Derivative [Line Items]
Fair value, asset of derivative instruments	3,219		27,215	3,219	27,215	10,505
Long-term debt, less current maturities | Cash Convertible Notes Embedded Derivative
Derivative [Line Items]
Fair value, (liabilities) of derivative instruments							$ (46,500)
Long-term debt, less current maturities | Not Designated as Hedging Instrument | Cash Convertible Notes Embedded Derivative
Derivative [Line Items]
Fair value, (liabilities) of derivative instruments	$ (3,219)		$ (27,215)	$ (3,219)	$ (27,215)	$ (10,505)
8.5% Unsecured notes due 2015
Derivative [Line Items]
Proceeds from settlement of forward currency contracts		$ 3,600
Non Recourse Debt | 8.5% Unsecured notes due 2015
Derivative [Line Items]
Stated interest rate	8.50%	8.50%	8.50%	8.50%	8.50%	8.50%