Share Capital (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2011 (shares)			258,669,487
Balance at December 31, 2011			$ 693,899
Deferred share units exercised	0	0	0	0
Balance at June 30, 2012 (shares)	258,950,971		258,950,971
Balance at June 30, 2012	694,480		694,480
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at December 31, 2011 (shares)			258,669,487
Balance at December 31, 2011			693,899
Option exercises (shares)			138,334
Option exercises			234
Deferred share units exercised (shares)			29,010
Deferred share units exercised			39
Unclaimed shares forfeited (shares)			(50,869)
Unclaimed shares forfeited			0
Bonus shares and other (shares)			165,009
Bonus shares and other			308
Balance at June 30, 2012 (shares)	258,950,971		258,950,971
Balance at June 30, 2012	$ 694,480		$ 694,480