Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss By Component) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	$ (8,149)	$ (14,176)	$ (13,016)
Other comprehensive gain (loss) before reclassifications	(2,739)	6,027	(1,159)
Amounts reclassified from accumulated other comprehensive loss	(236)	0	(1)
Other comprehensive gain (loss)	(2,975)	6,027	(1,160)
Accumulated other comprehensive loss, net of tax, ending balance	(11,124)	(8,149)	(14,176)
Foreign currency translaction adjustments [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	(9,567)	(14,544)	(13,079)
Other comprehensive gain (loss) before reclassifications	(2,273)	4,977	(1,465)
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Other comprehensive gain (loss)	(2,273)	4,977	(1,465)
Accumulated other comprehensive loss, net of tax, ending balance	(11,840)	(9,567)	(14,544)
Derivative instruments, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	1,478	286	0
Other comprehensive gain (loss) before reclassifications	(1,126)	1,192	286
Amounts reclassified from accumulated other comprehensive loss	(236)	0	0
Other comprehensive gain (loss)	(1,362)	1,192	286
Accumulated other comprehensive loss, net of tax, ending balance	116	1,478	286
Unrealized loss on investments, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	(41)	(74)	(95)
Other comprehensive gain (loss) before reclassifications	41	33	21
Amounts reclassified from accumulated other comprehensive loss	0	0	0
Other comprehensive gain (loss)	41	33	21
Accumulated other comprehensive loss, net of tax, ending balance	0	(41)	(74)
Other, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	(19)	156	158
Other comprehensive gain (loss) before reclassifications	619	(175)	(1)
Amounts reclassified from accumulated other comprehensive loss	0	0	(1)
Other comprehensive gain (loss)	619	(175)	(2)
Accumulated other comprehensive loss, net of tax, ending balance	$ 600	$ (19)	$ 156