CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets:
Allowance for doubtful accounts (in dollars)	$ 4,699	$ 3,601
Shareholders' equity:
Common shares, authorized (in shares)	65,000,000	65,000,000
Common shares, par value (in dollars per share)	$ 0.10	$ 0.10
Common shares, outstanding (in shares)	46,592,000	46,376,000