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	Dec. 31, 2017
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	$ (11,124)	$ (8,149)	$ (14,176)
Other comprehensive loss before reclassifications	(4,393)	(2,739)	6,027
Amounts reclassified from accumulated other comprehensive loss, net of tax	(1,242)	(236)
Other comprehensive loss	(5,635)	(2,975)	6,027
Accumulated other comprehensive loss, net of tax, ending balance	(16,759)	(11,124)	(8,149)
Foreign currency translaction adjustments [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	(11,840)	(9,567)	(14,544)
Other comprehensive loss before reclassifications	(585)	(2,273)	4,977
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0
Other comprehensive loss	(585)	(2,273)	4,977
Accumulated other comprehensive loss, net of tax, ending balance	(12,425)	(11,840)	(9,567)
Derivative instruments, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	116	1,478	286
Other comprehensive loss before reclassifications	(2,474)	(1,126)	1,192
Amounts reclassified from accumulated other comprehensive loss, net of tax	(1,242)	(236)
Other comprehensive loss	(3,716)	(1,362)	1,192
Accumulated other comprehensive loss, net of tax, ending balance	(3,600)	116	1,478
Unrealized loss on investments, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	0	(41)	(74)
Other comprehensive loss before reclassifications	0	41	33
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0
Other comprehensive loss	0	41	33
Accumulated other comprehensive loss, net of tax, ending balance	0	0	(41)
Other, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	600	(19)	156
Other comprehensive loss before reclassifications	(1,334)	619	(175)
Amounts reclassified from accumulated other comprehensive loss, net of tax	0	0
Other comprehensive loss	(1,334)	619	(175)
Accumulated other comprehensive loss, net of tax, ending balance	$ (734)	$ 600	$ (19)