v2.4.0.8
Commitments and contingencies (Details) (Shareholder class action lawsuits, CAD)
 0 Months Ended 6 Months Ended
Jun. 06, 2013
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May 22, 2013
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May 07, 2013
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Apr. 02, 2013
Mar. 19, 2013
Jun. 30, 2013
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Commitments and contingencies            
Number of purported securities fraud class action complaints filed           5
Number of notices of actions relating to Canadian securities class action claims           3
Number of District Court actions alleged in specific period           5
Number of investors filed motion     6      
Number of lead plaintiffs applicants filed oppositions   3        
Number of lead plaintiffs applicants filed replies 3          
Amount of alleged damages       208,500,000 1,100,000,000  
July 23, 2010 to March 4, 2013
            
Commitments and contingencies            
Number of District Court actions alleged in specific period           3
August 8, 2012 to February 28, 2013
            
Commitments and contingencies            
Number of District Court actions alleged in specific period           2