Condensed Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Share data	Sep. 30, 2011	Dec. 31, 2010
Trade accounts receivable, allowance for doubtful accounts	$ 7,621	$ 7,250
Common shares, par value	$ 0.10	$ 0.10
Common shares, shares authorized	50,000,000	50,000,000
Common shares, issued	18,411,073	17,726,645
Common shares, outstanding	18,411,073	17,726,645