Derivative Financial Instruments Derivative Instruments Designated as Cash Flow Hedges OCI Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Other Comprehensive Income (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ 506	$ (9,431)
Other Comprehensive Income (Loss) [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) , Net of Intercompany, Gain (loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	629	(129)
Interest rate swap agreements [Member] | Other Comprehensive Income (Loss) [Member] | Designated as Hedging Instrument [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(123)	(9,302)
British pound forward contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(1,000)	2,500
Intercompany Loan [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Foreign Currency Transaction Gain (Loss), Net of Tax	$ 1,600	$ (2,600)