Accumulated Other Comprehensive Income (Schedule Of AOCI) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	$ (9,233)	$ (53,842)
Other comprehensive income before reclassifications	4,521	(8,128)
Gains reclassified from accumulated other comprehensive income	(3,313)	2,039
Balance end of period	171,549	(40,849)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(41,791)	(36,470)
Balance end of period	(40,583)	(42,559)
Unrealized (Loss) Gain on Investments, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(157)	(22)
Other comprehensive income before reclassifications	362	150
Gains reclassified from accumulated other comprehensive income	0	0
Balance end of period	205	128
Unrealized Gain (Loss) on Derivative Instruments, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	7,589	(5,219)
Other comprehensive income before reclassifications	1,978	5,786
Gains reclassified from accumulated other comprehensive income	(3,313)	2,039
Balance end of period	6,254	2,606
Unrealized (Loss) Gain on Net Investment Hedge, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(394)	(4,311)
Other comprehensive income before reclassifications	500	2,263
Gains reclassified from accumulated other comprehensive income	0	0
Balance end of period	106	(2,048)
Cumulative Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(48,829)	(26,918)
Other comprehensive income before reclassifications	1,681	(16,327)
Gains reclassified from accumulated other comprehensive income	0	0
Balance end of period	$ (47,148)	$ (43,245)