Derivative Financial Instruments Derivative Instruments Not Designated as Hedges Amount Recognized in Earnings (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Not Designated as Hedging Instrument [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	$ (809)	$ 0	$ 3,667	$ 0
Other Nonoperating Income (Expense) [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, Net of Foreign Currency Transaction Gain (Loss) on Intercompany Loan	(809)	$ 0	3,667	$ 0
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	11,200		(3,500)
Intercompany GRail Loan [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Transaction Gain (Loss), Net of Tax	$ (12,000)		$ (200)