Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 59,690	$ 48,866	$ 41,899
Other comprehensive income (loss):
Cumulative effect of accounting change due to ASU 2018-02			(40)
Pension benefit obligations	(80)	(1,032)	76
Foreign currency translation adjustments	27,242	(2,722)	(19,602)
Unrealized gain on foreign currency derivative securities, net of tax	211	899	796
Unrealized loss on commodity derivative securities, net of tax			(286)
Other comprehensive income (loss), net of tax	27,373	(2,855)	(19,056)
Comprehensive income	$ 87,063	$ 46,011	$ 22,843