Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss By Component) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 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			3,289
Other comprehensive income (loss)	$ 2,325	$ (1,477)	3,289	$ (2,367)
Accumulated other comprehensive loss, net of tax, ending balance	(10,887)		(10,887)
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			3,121
Other comprehensive income (loss)			3,121
Accumulated other comprehensive loss, net of tax, ending balance	(11,423)		(11,423)
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			165
Other comprehensive income (loss)			165
Accumulated other comprehensive loss, net of tax, ending balance	451		451
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			16
Other comprehensive income (loss)			16
Accumulated other comprehensive loss, net of tax, ending balance	(58)		(58)
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)
Other comprehensive income (loss)			(13)
Accumulated other comprehensive loss, net of tax, ending balance	$ 143		$ 143