Accumulated Other Comprehensive Income (Schedule of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	$ (53,842)	$ (108,213)
Other comprehensive (loss) income before reclassifications	(6,110)	6,386
Gains reclassified from accumulated other comprehensive income	789	197
Balance end of period	(9,233)	(53,842)
Unrealized Gain (Loss) on Investments, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(22)	20
Other comprehensive (loss) income before reclassifications	(135)	(42)
Gains reclassified from accumulated other comprehensive income	0	0
Balance end of period	(157)	(22)
Unrealized Gain (Loss) on Derivatives Instruments, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(5,219)	4,916
Other comprehensive (loss) income before reclassifications	12,019	(10,332)
Gains reclassified from accumulated other comprehensive income	789	197
Balance end of period	7,589	(5,219)
Unrealized Gain (Loss) on Net Investment Hedge, Net of Tax
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(4,311)	4,036
Other comprehensive (loss) income before reclassifications	3,917	(8,347)
Gains reclassified from accumulated other comprehensive income	0	0
Balance end of period	(394)	(4,311)
Cumulative Translation Adjustment
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(26,918)	(52,025)
Other comprehensive (loss) income before reclassifications	(21,911)	25,107
Gains reclassified from accumulated other comprehensive income	0	0
Balance end of period	(48,829)	(26,918)
Accumulated Other Comprehensive Loss
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance beginning of period	(36,470)	(43,053)
Balance end of period	$ (41,791)	$ (36,470)