CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (4,128)	$ 3,952	$ 19,808
Other comprehensive income (loss), net of tax:
Change in foreign currency translation adjustments	(268)	(200)	(85)
Pension benefit plan	2,152	(662)	(980)
Total comprehensive income (loss)	$ (2,244)	$ 3,090	$ 18,743