Consolidated Condensed Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 24,146	$ 15,887	$ 25,697	$ 27,052
Other comprehensive income (loss):
Foreign currency translation adjustments	14,362	(15,172)	11,569	(15,943)
Unrealized gain (loss) on foreign currency derivative securities, net of tax	997	(202)	(1,614)	629
Other comprehensive income (loss), net of tax	15,359	(15,374)	9,955	(15,314)
Comprehensive income	$ 39,505	$ 513	$ 35,652	$ 11,738