Consolidated Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Consolidated Condensed Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 483	$ 332
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	1,000,000	1,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 1.00	$ 1.00
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	6,944,000	6,900,000
Common stock, shares outstanding	6,944,000	6,900,000