Derivative Financial Instruments Derivative Financial Instruments Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net unrealized loss on hedging instruments	(136,514,000)	$ (21,722,000)
Long-term Debt	323,969,000
Forward Contracts [Member]
Number of foreign exchange forward contracts entered into YTD	517
Number of Counterparties [Member]
Number of foreign exchange forward contracts entered into YTD	Our derivative assets and liabilities consist of foreign exchange forward and interest rate swap contracts with eight counterparties at December 31, 2014 and seven counterparties at December 31, 2013.
Interest Rate Swap [Member] | 2011 Credit Facility USD Term Loan Interest Rate Swaps [Member]
Derivative, Number of Instruments Held	6
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	1,300,000
Derivative, Notional Amount	200,000,000
Secured Debt [Member]
Long-term Debt	323,969,000	378,750,000
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Nonderivative Instruments [Member]
Net unrealized loss on hedging instruments	(14,380,000)	(14,380,000)	(14,380,000)	(14,380,000)
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Nonderivative Instruments [Member] | Net Investment Hedging [Member]
Net unrealized loss on hedging instruments	(14,400,000)	(14,400,000)
London Interbank Offered Rate (LIBOR) [Member] | Secured Debt [Member]
Long-term Debt	292,500,000
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Minimum [Member]
Derivative, Notional Amount	86,000
Not Designated as Hedging Instrument [Member] | Foreign Exchange Contract [Member] | Maximum [Member]
Derivative, Notional Amount	20,700,000