Accumulated Other Comprehensive Income (Loss) (Schedule Of Accumulated Other Comprehensive Income (Loss) By Component) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 615,948	$ 626,700
Other comprehensive income (loss)	(18,843)	31,689
Amounts reclassified from accumulated other comprehensive income	1,401
Ending balance	575,987	615,948
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(19,319)	(50,738)
Other comprehensive income (loss)	(18,751)	31,419
Amounts reclassified from accumulated other comprehensive income	1,401
Ending balance	(36,669)	(19,319)
Defined benefit pension plan
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,555)	(2,775)
Other comprehensive income (loss)	(92)	220
Amounts reclassified from accumulated other comprehensive income	0
Ending balance	(2,647)	(2,555)
Liquidation of non-US entity and purchase of non-controlling interests
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	338	288
Other comprehensive income (loss)	0	50
Amounts reclassified from accumulated other comprehensive income	0
Ending balance	338	338
Accumulated Other Comprehensive (Loss) Income
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(21,536)	(53,225)
Ending balance	$ (38,978)	$ (21,536)