CONDENSED CONSOLIDATED BALANCE SHEETS (unaudited) (Parenthetical) (USD $)	Mar. 31, 2013	Dec. 31, 2012
EQUITY
Preferred Shares, par value (in dollars per share)	$ 0	$ 0
Preferred Shares, authorized (in shares)	1,000,000	1,000,000
Preferred Shares, issued (in shares)	0	0
Common shares, par value (in dollars per share)	$ 0	$ 0
Common shares, authorized (in shares)	75,000,000	75,000,000
Common shares, issued (in shares)	54,912,781	51,183,318
Common shares, outstanding (in shares)	52,551,813	49,383,209
Treasury stock (in shares)	2,360,968	1,800,109