Derivative Instruments And Hedging Activities - Impact Of Derivative Instruments Designated As Hedging Instruments On Accumulated OCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative Instruments, Net of Tax (Effective Portion)	$ 10,514	$ 9,870	$ 4,200
Foreign Exchange Contracts [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative Instruments, Net of Tax (Effective Portion)	9,732	9,397	4,734
Interest Rate Swaps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative Instruments, Net of Tax (Effective Portion)	$ 782	$ 473	$ (534)