CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 9,284	$ 1,930	$ 14,891	$ (11,490)	$ (7,230)
Other comprehensive income (loss), net of tax:
Change in foreign currency translation adjustments	143	(216)	26	(430)	(304)
Pension benefit plan	153	(68)	(495)	(811)	(1,063)
Total comprehensive income (loss)	$ 9,580	$ 1,646	$ 14,422	$ (12,731)	$ (8,597)