Annual report pursuant to Section 13 and 15(d)

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

v3.6.0.2
Income Tax - Summary of Years Open to Examination under Different Jurisdiction (Detail)
 12 Months Ended
Dec. 31, 2016
Earliest Tax Year [Member] | Canada [Member]  
Income Tax Examination [Line Items]  
Years open to examination 2008
Earliest Tax Year [Member] | US [Member]  
Income Tax Examination [Line Items]  
Years open to examination 2013
Latest Tax Year [Member] | Canada [Member]  
Income Tax Examination [Line Items]  
Years open to examination 2016
Latest Tax Year [Member] | US [Member]  
Income Tax Examination [Line Items]  
Years open to examination 2016