Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 31,579	$ 12,967
Other comprehensive (loss) income:
Cumulative translation adjustment	(1,061)	124
Unrealized gains (losses) on marketable securities, net of tax of $0 in both periods	99	(26)
Total other comprehensive (loss) income	(962)	98
Comprehensive income	$ 30,617	$ 13,065

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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