Summary of Significant Accounting Policies (Summary of Changes in Accumulated Balances of Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance, Estimated tax (expense) benefit	$ (351)
Other comprehensive income (loss) before reclassifications, Estimated tax (expense) benefit	(2,493)
Amount of loss (gain) reclassified from accumulated other comprehensive loss, Estimated tax (expense) benefit	365
Net current period other comprehensive income (loss), Estimated tax (expense) benefit	(2,128)
Ending Balance, Estimated tax (expense) benefit	(2,479)
Beginning Balance	(406,671)
Other comprehensive income (loss) before reclassifications, net of tax	(88,348)
Amount of loss (gain) reclassified from accumulated other comprehensive loss, net of tax	(1,705)
Net current period other comprehensive income (loss), net of tax	(90,053)	$ (1,011)
Ending Balance	(496,724)
Unrealized (Losses) Gains on Hedging Activities, Net [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(250)
Other comprehensive (loss) income before reclassifications, before tax	5,852
Amount of (gain) loss reclassified from accumulated other comprehensive loss, before tax	(41)
Net current period other comprehensive income (loss), before tax	5,811
Ending Balance	5,561
Unrealized (Losses) Gains on Investments [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	2,029
Other comprehensive (loss) income before reclassifications, before tax	2,890
Amount of (gain) loss reclassified from accumulated other comprehensive loss, before tax	(2,029)
Net current period other comprehensive income (loss), before tax	861
Ending Balance	2,890
Foreign Currency Translation [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Beginning Balance	(408,099)
Other comprehensive (loss) income before reclassifications, before tax	(94,597)
Net current period other comprehensive income (loss), before tax	(94,597)
Ending Balance	$ (502,696)