CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) (USD $)	Sep. 30, 2012	Dec. 31, 2011
EQUITY
Preferred shares, par value (in dollars per share)	$ 0	$ 0
Preferred shares, shares authorized (in shares)	1,000,000	1,000,000
Preferred shares, shares issued (in shares)	0	0
Common shares, par value (in dollars per share)	$ 0	$ 0
Common shares, shares authorized (in shares)	75,000,000	75,000,000
Common shares, shares issued (in shares)	50,868,932	50,321,962
Common shares, shares outstanding (in shares)	49,162,758	49,035,788
Treasury stock at cost (in shares)	1,706,174	1,286,174