Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 7,788	$ 6,064	$ 6,055	$ 9,094
Other comprehensive income (loss), net of taxes:
Foreign currency translation	(3,394)	2,514	(1,691)	3,304
Net change in market value of investments	62	7	(53)	24
Other comprehensive income (loss)	(3,332)	2,521	(1,744)	3,328
Comprehensive income	$ 4,456	$ 8,585	$ 4,311	$ 12,422

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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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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