Derivative Financial Instruments Derivative Financial Instruments Narrative (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2015 USD ($) contracts	Dec. 31, 2014 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)
Net unrealized loss on hedging instruments	$ 182,742	$ 136,514
Forward Contracts [Member]
Description of Derivative Activity Volume	276
Secured Debt [Member]
Long-term Debt	$ 372,958	323,969
Interest Rate Swap [Member] | Credit Facility USD Term Loan Interest Rate Swaps [Member]
Number of Interest Rate Derivatives Held | contracts	6
Derivative, Notional Amount	$ 200,000
Pay fixed interest rate in interst rate swap	1.00%
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$ (1,200)
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Minimum [Member]
Derivative, Notional Amount	150
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Maximum [Member]
Derivative, Notional Amount	22,000
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Nonderivative Instruments [Member]
Net unrealized loss on hedging instruments	14,380	$ 14,380	$ 14,380	$ 14,380
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Nonderivative Instruments [Member] | Net Investment Hedging [Member]
Net unrealized loss on hedging instruments	$ 14,400		$ 14,400
Number of Counterparties [Member]
Derivative Counterparties	8	8
London Interbank Offered Rate (LIBOR) [Member] | Secured Debt [Member]
Long-term Debt	$ 345,000