CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Allowance for doubtful accounts	$ 4,430	$ 3,601
Shareholders’ equity:
Common shares, authorized	65,000,000	65,000,000
Common shares, par value (in dollars per share)	$ 0.10	$ 0.1
Common shares, outstanding	46,630,000	46,376,000