Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Receivables, allowance for doubtful accounts	$ 1,131	$ 3,041
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	18,312,000	12,652,000
Common stock, shares outstanding	18,312,000	12,652,000