Derivative Financial Instruments Derivative Instruments Not Designated as Hedges Amount Recognized in Earnings (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ (2,762)	$ (2,859)
Other loss, net [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments, Net of Foreign Currency Transaction Gain (Loss) on Intercompany Loan	(2,762)	(2,859)
Currency Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments		(10,900)
Intercompany GRail Loan [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Transaction Gain (Loss), Net of Tax	(8,200)	$ 8,000
Mark to Market [Member] | Currency Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	7,300
Interest Expense Accrual [Member] | Currency Swap [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ (1,900)