Comprehensive Income (Schedule Of Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	$ (38,090)	$ (11,664)
Current-period other comprehensive income	5,181	(18,123)
Reclassified from accumulated OCI into income	2,498	(19,428)
Income tax benefit (expense)	(4,210)	11,125	$ (308)
Ending Balance	(34,621)	(38,090)	(11,664)
Currency Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(31,871)	(17,304)
Current-period other comprehensive income	(5,697)	(19,240)
Income tax benefit (expense)	394	4,673
Ending Balance	(37,174)	(31,871)	(17,304)
Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(857)	(1,399)
Current-period other comprehensive income	210	701
Income tax benefit (expense)	(22)	(159)
Ending Balance	(669)	(857)	(1,399)
Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance	(5,362)	7,039
Current-period other comprehensive income	10,668	416
Reclassified from accumulated OCI into income	2,498	(19,428)
Income tax benefit (expense)	(4,582)	6,611
Ending Balance	$ 3,222	$ (5,362)	$ 7,039