Consolidated Balance Sheets (Parenthetical) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Consolidated Balance Sheets
First preferred shares, no par value
First preferred shares, shares issued	0	0
First preferred shares, shares outstanding	0	0
Common shares, no par value
Common shares, shares issued	258,861,960	258,669,487
Common shares, shares outstanding	258,861,960	258,669,487