v3.19.3.a.u2
Income tax expense - Reconciliation (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Reconciliation of income taxes      
Computed income tax (benefit) expense at Canadian statutory rate $ (9.2) $ 10.1 $ (39.3)
Operating in countries with different income tax rates 0.1 0.1 (20.1)
Income tax benefit after adjustments for countries with different income tax rates (9.1) 10.2 (59.4)
Change in valuation allowance 5.7 (6.7) (34.6)
Income tax benefit after adjustments for countries with different income tax rates and valuation allowance (3.4) 3.5 (94.0)
Dividend withholding tax and other cash taxes 1.3 0.5 0.2
Foreign exchange 1.7   (2.4)
Changes in tax rates 2.2 (3.3) (1.5)
Remeasurement of deferred tax assets and liabilities     28.5
Capital gain (loss) on intercompany notes 0.1 (1.1) (0.1)
Impairments 7.7   9.9
Other 0.2 0.6 1.3
Total other reconciliation items 13.2 (3.3) 35.9
Total income tax expense (benefit), net $ 9.8 $ 0.2 $ (58.1)
Canada.      
Reconciliation of income taxes      
Enacted statutory income tax rate 27.00% 27.00% 27.00%
Computed income tax (benefit) expense at Canadian statutory rate $ (9.2) $ 10.1  
Change in valuation allowance $ 7.9 $ (0.1)