Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Current assets:
Allowance for doubtful accounts	$ 773	$ 654
Stockholders' Equity Attributable to Parent [Abstract]
Preferred stock, par value in USD per share)	$ 1	$ 1
Preferred stock, shares authorized (in shares)	500,000	500,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in USD per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	35,000,000	35,000,000
Common stock, shares issued (in shares)	9,293,401	9,287,625
Common stock, shares outstanding (in shares)	9,066,547	9,061,039
Treasury stock (in shares)	226,854	226,586