Annual report pursuant to Section 13 and 15(d)

Income Tax - Summary of Years Open to Examination under Different Jurisdiction (Detail)

v2.4.1.9
Income Tax - Summary of Years Open to Examination under Different Jurisdiction (Detail)
 12 Months Ended
Dec. 31, 2014
Earliest Tax Year [Member] | Canada [Member]  
Income Tax Examination [Line Items]  
Years open to examination 2007
Earliest Tax Year [Member] | US [Member]  
Income Tax Examination [Line Items]  
Years open to examination 2011
Latest Tax Year [Member] | Canada [Member]  
Income Tax Examination [Line Items]  
Years open to examination 2014
Latest Tax Year [Member] | US [Member]  
Income Tax Examination [Line Items]  
Years open to examination 2014