Condensed Consolidated Statements of Financial Position (Parenthetical) (USD $) In Thousands, except Share data	Jun. 30, 2011	Dec. 31, 2010
Current Assets
Allowances for accounts receivable	$ 4,020	$ 2,950
Shareholders' Equity
Preferred Shares, shares authorized	1,000,000	1,000,000
Preferred Shares, shares issued	0	0
Preferred Shares, shares outstanding	0	0
Common Shares, par value	$ 0	$ 0
Common Shares, shares authorized	60,000,000	60,000,000
Common Shares, shares outstanding	34,985,304	35,315,732
Treasury Shares, shares	2,845,753	2,592,175