CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Consolidated Statement Of Comprehensive Income [Abstract]
Net income	$ 5,526	$ 14,697	$ 13,102	$ 29,827
Other comprehensive income:
Change in net unrealized gains on marketable securities, net of tax	114	107	209	130
Change in currency translation adjustments	316	(855)	(202)	(223)
Total comprehensive income	$ 5,956	$ 13,949	$ 13,109	$ 29,734

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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