CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
CONDENSED CONSOLIDATED BALANCE SHEETS
Trade receivables, provision for credit losses	$ 509	$ 382
Common stock, par value (in dollars per share)	$ 0	$ 0
Common stock, authorized shares	50,000	50,000
Common stock, shares issued	14,724	14,632
Common stock, shares outstanding	14,724	14,632
Preferred stock, par value (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, authorized shares	5,000	5,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0