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Income Taxes - Components of Income Tax Expense (Details) - CAD CAD in Thousands |  |  |  |  | 12 Months Ended
--- | --- | --- | --- | --- | ---
Feb. 03, 2016 | Feb. 02, 2016 | Jun. 18, 2015 | Jun. 17, 2015 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Current income tax expense(1) |  |  |  |  | CAD 79,000 | CAD 23,000 | CAD 24,000
Adjustments in respect of current income tax of previous years |  |  |  |  | 0 | 0 | (5,000)
Adjustments in respect of deferred income tax of previous years |  |  |  |  | 0 | (3,000) | 5,000
Deferred income tax expense related to the origination and reversal of temporary differences |  |  |  |  | (110,000) | 16,000 | 22,000
Deferred income tax expense related to temporary difference on investment in subsidiary |  |  |  |  | 0 | 11,000 | 95,000
Deferred income tax expense resulting from changes in tax rates or laws |  |  |  |  | 110,000 | 1,000 | 20,000
Reversal of writedown of deferred income tax assets |  |  |  |  | (15,000) | (10,000) | (56,000)
Income tax expense |  |  |  |  | 64,000 | 38,000 | 105,000
Current income tax expense |  |  |  |  | 79,000 | 23,000 | 19,000
Deferred income tax expense (recovery) |  |  |  |  | (15,000) | 15,000 | CAD 86,000
Deferred income tax liabilities (Note 10) |  |  |  |  | 549,000 | CAD 712,000 |
Net deferred tax assets |  |  |  |  | 6,000 |  |
Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Deferred Tax Asset, Income Tax Expense (Benefit) |  |  |  |  | 104,000 |  |
Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Deferred Tax Liability, Income Tax (Expense) Benefit |  |  |  |  | 110,000 |  |
Deferred tax expense (income) recognised in profit or loss |  |  |  |  | 1,000 |  |
Tax Cuts and Jobs Act of 2017, Change in Tax Rate, Deferred Tax Recovery |  |  |  |  | CAD 111,000 |  |
Corporate tax rate |  |  |  |  | 26.80% | 26.70% | 25.90%
New Brunswick |  |  |  |  |  |  |
Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Corporate tax rate | 1400.00% | 1200.00% |  |  |  |  |
Alberta |  |  |  |  |  |  |
Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Corporate tax rate |  |  | 1200.00% | 1000.00% |  |  |
Solomon Power Station |  |  |  |  |  |  |
Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Current income tax expense(1) |  |  |  |  | CAD 56,000 |  |
Canadian Assets |  |  |  |  |  |  |
Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Deferred income tax liabilities (Note 10) |  |  |  |  |  | CAD 8,000 |
Australian Assets |  |  |  |  |  |  |
Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Deferred income tax liabilities (Note 10) |  |  |  |  |  |  | CAD 95,000
New Richmond |  |  |  |  |  |  |
Disposal Groups, Including Discontinued Operations [Line Items] |  |  |  |  |  |  |
Deferred income tax liabilities (Note 10) |  |  |  |  | CAD 3,000 |  |

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