Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss By Component) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 575,987	$ 615,948
Other comprehensive income (loss)	1,931	(18,843)
Amounts reclassified from accumulated other comprehensive income		1,401
Ending Balance	513,896	575,987
Foreign currency translation adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(36,669)	(19,319)
Other comprehensive income (loss)	3,053	(18,751)
Amounts reclassified from accumulated other comprehensive income		1,401
Ending Balance	(33,616)	(36,669)
Defined benefit pension plan
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(2,647)	(2,555)
Other comprehensive income (loss)	(1,060)	(92)
Amounts reclassified from accumulated other comprehensive income		0
Ending Balance	(3,707)	(2,647)
Derivative financial instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	0	0
Other comprehensive income (loss)	(318)	0
Amounts reclassified from accumulated other comprehensive income		0
Ending Balance	(318)	0
Liquidation of non-US entity and purchase of non-controlling interests
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	338	338
Other comprehensive income (loss)	256	0
Amounts reclassified from accumulated other comprehensive income		0
Ending Balance	594	338
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(38,978)	(21,536)
Ending Balance	$ (37,047)	$ (38,978)