v3.19.3.a.u2
Income tax expense - Other (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Reconciliation of income taxes      
Tax expense $ 9.8 $ 0.2 $ (58.1)
Computed income tax (benefit) expense at Canadian statutory rate (9.2) 10.1 (39.3)
Impact related to withholding and state taxes   0.5  
Other permanent differences 0.4 0.7  
Deferred tax assets 10.4 7.0  
Deferred tax liabilities 23.7 16.0  
Net deferred tax liability (13.3) (9.0)  
Net deferred tax liability   9.0  
Capital gain (loss) on intercompany notes 0.1 (1.1) (0.1)
Changes in tax rates 2.2 (3.3) (1.5)
Valuation allowance 145.4 139.7  
Increase (decrease) in the valuation allowance 5.7 (6.7) (34.6)
Operating in countries with different income tax rates 0.1 0.1 (20.1)
Foreign exchange 1.7   (2.4)
Dividend withholding tax and other cash taxes 1.3 0.5 0.2
Impairments 7.7   $ 9.9
US      
Reconciliation of income taxes      
Net deferred tax liability (23.7) (16.0)  
Increase (decrease) in the valuation allowance $ (2.2) $ (6.6)  
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  
Net deferred tax liability 10.4 7.0  
Increase (decrease) in the valuation allowance $ 7.9 $ (0.1)