Consolidated Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Consolidated Condensed Balance Sheets [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 368	$ 807
Common stock, par value	$ 1.00	$ 1.00
Common stock, shares authorized	20,000,000	20,000,000
Common stock, shares issued	8,714,000	8,664,000
Common stock, shares outstanding	8,714,000	8,664,000