Accumulated Other Comprehensive Income (Loss) (Schedule Of Accumulated Other Comprehensive Income (Loss) By Component) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Beginning Balance	$ (53,225)	$ (39,548)
Other comprehensive income (loss)	31,689	(13,677)
Ending Balance	(21,536)	(53,225)
Foreign Currency Translation Adjustment [Member]
Beginning Balance	(50,738)	(37,675)
Other comprehensive income (loss)	31,419	(13,063)
Ending Balance	(19,319)	(50,738)
Defined Benefit Pension Plan [Member]
Beginning Balance	(2,775)	(1,873)
Other comprehensive income (loss)	220	(902)
Ending Balance	(2,555)	(2,775)
Liquidation Of Non-US Entity And Purchase Of Non-controlling Interests [Member]
Beginning Balance	288
Other comprehensive income (loss)	50	288
Ending Balance	$ 338	$ 288