Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Accounts receivable, less allowance for doubtful accounts	$ 654	$ 593
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)	9,287,625	9,190,171
Common stock, shares outstanding (in shares)	9,061,039	9,043,771
Treasury stock (in shares)	226,586	146,400