Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Current assets
Allowance for doubtful accounts and discounts	$ 1,350	$ 1,100
Stockholders' equity
Preferred stock, no par value
Preferred stock, shares authorized	2,500	2,500
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, no par value
Common stock, shares authorized	40,000	40,000
Common stock, shares issued	17,274	17,274
Common stock, shares outstanding	15,604	15,710