XML 144 R111.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Income taxes - Income (Loss) Before Taxes (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]    
Income/(loss) before taxes $ 555,067 $ 132,461
Canada    
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]    
Income/(loss) before taxes 351,908 (109,537)
U.S.    
Schedule of Components of Income Before Income Tax Expense (Benefit) [Line Items]    
Income/(loss) before taxes $ 203,159 $ 241,998