Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Trade accounts receivable, allowance for doubtful accounts	$ 4,848	$ 3,987
Common shares, par value	$ 0.10	$ 0.10
Common shares, authorized	50,000,000	50,000,000
Common shares, issued	19,423,874	19,022,619
Common shares, outstanding	19,423,874	19,022,619