Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss By Component) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	$ (14,176)
Other comprehensive gain (loss) before reclassifications	964
Other comprehensive loss	964	$ (890)
Accumulated other comprehensive loss, net of tax, ending balance	(13,212)
Foreign currency translaction adjustments [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	(14,544)
Other comprehensive gain (loss) before reclassifications	608
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive loss	608
Accumulated other comprehensive loss, net of tax, ending balance	(13,936)
Derivative instruments, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	286
Other comprehensive gain (loss) before reclassifications	365
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive loss	365
Accumulated other comprehensive loss, net of tax, ending balance	651
Unrealized loss on investments, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	(74)
Other comprehensive gain (loss) before reclassifications	4
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive loss	4
Accumulated other comprehensive loss, net of tax, ending balance	(70)
Other [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	156
Other comprehensive gain (loss) before reclassifications	(13)
Amounts reclassified from accumulated other comprehensive loss	0
Other comprehensive loss	(13)
Accumulated other comprehensive loss, net of tax, ending balance	$ 143