Accumulated Other Comprehensive Income - Accumulated Other Comprehensive Income Roll Forward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning Balance, Unrealized Gains (Losses) on Investments	$ 0	$ 0	$ 2,449
Beginning Balance, Foreign Currency Translation	(29,090)	(54,649)	(31,573)
Beginning Balance, Total	(29,090)	(54,649)	(29,124)
Other comprehensive income (loss) before reclassifications, Unrealized Gain (Losses) on Investments	(1,418)	0	744
Other comprehensive income (loss) before reclassifications, Foreign Currency Translation	(15,471)	25,559	(23,076)
Other comprehensive income (loss) before reclassifications, Total	(16,889)	25,559	(22,332)
Amounts reclassified from accumulated other comprehensive income, Unrealized Gains (Losses) on Investments			3,193
Amounts reclassified from accumulated other comprehensive income, Foreign Currency Translation			0
Amounts reclassified from accumulated other comprehensive income, Total	0	0	(3,193)
Net decrease in other comprehensive income, Unrealized Gains (Losses) on Investments	(1,418)	0	(2,449)
Net decrease in other comprehensive income, Foreign Currency Translation	(15,471)	25,559	(23,076)
Net decrease in other comprehensive income, Total	(16,889)	25,559	(25,525)
Ending Balance, Unrealized Gains (Losses) on Investments	(1,418)	0	0
Ending Balance, Foreign Currency Translation	(44,561)	(29,090)	(54,649)
Ending Balance, Total	$ (45,979)	$ (29,090)	$ (54,649)