Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 35,341	$ 51,427	$ 25,140
Reclassification adjustment from loss on partial settlement of pension plan, net of tax	4,291	1,066	0
Pension liability adjustment, net of tax	(810)	924	139
Change in fair value of derivative financial instrument, net of tax	(12,490)	194	(506)
Foreign currency translation adjustment, net of tax	(12,720)	24,038	(11,887)
Total other comprehensive (loss) income:	(21,729)	26,222	(12,254)
Total comprehensive income	$ 13,612	$ 77,649	$ 12,886