Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 476	$ 454
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	500,000	500,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 1.00	$ 1.00
Common stock, shares authorized	35,000,000	35,000,000
Common stock, shares issued	8,921,302	8,864,929
Common stock, shares outstanding	8,888,028	8,832,623
Treasury Stock, Shares	33,274	32,306