XML 185 R101.htm IDEA: XBRL DOCUMENT v2.4.0.6
Income Taxes - Additional Information (Detail) (USD $)
Jul. 31, 2012
Apr. 30, 2012
Apr. 30, 2011
Apr. 30, 2010
Apr. 30, 2009
Income Taxes [Line Items]          
Capital losses   $ 184,600,000 $ 184,800,000    
Non-capital losses   494,600,000 430,600,000    
Unrecognized tax benefits, income tax penalties and interest accrued 2,900,000 2,900,000 3,100,000    
Unrecognized tax benefits 13,200,000 15,925,000 15,302,000 16,448,000 15,834,000
Unrecognized tax benefits that would impact effective tax rate 6,400,000        
Other Foreign Jurisdiction
         
Income Taxes [Line Items]          
Capital losses   184,600,000 184,800,000    
Non-capital losses   242,800,000 152,600,000    
LUXEMBOURG
         
Income Taxes [Line Items]          
Non-capital losses   $ 251,800,000 $ 278,000,000