Derivative Financial Instruments Derivative Instruments Not Designated as Hedges Amount Recognized in Earnings (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 0	$ 0	$ 0	$ (18,686)
British pound forward contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments				18,700
British pound forward contracts [Member] | Loss on settlement of foreign currency forward purchase contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Foreign Currency Derivative Instruments Not Designated as Hedging Instruments	$ 0	$ 0	$ 0	$ (18,686)