Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,883	$ 1,920
Common stock, par value
Common stock, shares authorized	40,000,000	40,000,000
Common stock, shares issued	24,182,000	24,052,000
Common Stock, shares outstanding	24,182,000	24,052,000