Derivative Financial Instruments Effect of Derivative Instruments Not Designated as Hedges (Details) (Not Designated as Hedging Instrument [Member], USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Derivative Instruments, Gain (Loss) [Line Items]
Amount recognized in earnings, net	$ (1,270,000)	$ (2,269,000)	$ (54,441,000)
Interest (expense)/income | Cross-currency swap agreement [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount recognized in earnings	(1,184,000)	(2,696,000)	(4,638,000)
Other income/(loss), net | Cross-currency swap agreement [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount recognized in earnings	(86,000)	427,000	303,000
Contingent Forward Sale Contract Mark-to-market Expense [Member] | Contingent forward sale contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount recognized in earnings	$ 0	$ 0	$ (50,106,000)