Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net Income (loss)	$ (52,982)	$ (19,342)	$ 23,840
Other Comprehensive Income (Loss), net of tax
Net unrealized gains (losses) on available-for-sale securities	279	(3,130)	2,163
Defined benefit plan adjustments	(1,185)	(3,755)	731
Foreign currency translation	(1,480)	(4,236)	5,999
Other Comprehensive Income (Loss), net of tax	(2,386)	(11,121)	8,893
Comprehensive Income (Loss), net of tax	$ (55,368)	$ (30,463)	$ 32,733