Accumulated Other Comprehensive Loss (Schedule Of Accumulated Other Comprehensive Loss By Component) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	$ (9,475)	$ (9,094)	$ (10,536)
Other comprehensive gain (loss) before reclassifications	(3,528)	(3,281)	1,442
Amounts reclassified from accumulated other comprehensive loss	(13)	2,900
Other comprehensive income (loss)	(3,541)	(381)	1,442
Accumulated other comprehensive loss, net of tax, ending balance	(13,016)	(9,475)	(9,094)
Foreign currency translaction adjustments [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	(9,688)	(8,090)	(8,681)
Other comprehensive gain (loss) before reclassifications	(3,391)	(4,528)	591
Amounts reclassified from accumulated other comprehensive loss	0	2,930
Other comprehensive income (loss)	(3,391)	(1,598)	591
Accumulated other comprehensive loss, net of tax, ending balance	(13,079)	(9,688)	(8,090)
Unrealized loss on investments, net of tax [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	(64)	(1,433)	(1,851)
Other comprehensive gain (loss) before reclassifications	(31)	1,369	418
Amounts reclassified from accumulated other comprehensive loss	0	0
Other comprehensive income (loss)	(31)	1,369	418
Accumulated other comprehensive loss, net of tax, ending balance	(95)	(64)	(1,433)
Other [Member]
Accumulated other comprehensive income loss [Line Items]
Accumulated other comprehensive loss, net of tax, beginning balance	277	429	(4)
Other comprehensive gain (loss) before reclassifications	(106)	(122)	433
Amounts reclassified from accumulated other comprehensive loss	(13)	(30)
Other comprehensive income (loss)	(119)	(152)	433
Accumulated other comprehensive loss, net of tax, ending balance	$ 158	$ 277	$ 429