Income Taxes (Narrative) (Details) - CAD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Income from continuing operations before income taxes	$ 137.8	$ 71.3	$ 93.8
Capital losses	0.2	27.2
Non capital losses	0.1	0.0
Non-capital loss expire in 2038	0.3
Tax Basis of Investments in the Limited Partnership	1,100.0
Investment in partnerships	$ 144.4	$ 117.4
Effective income tax rate, discontinued operations	(5.20%)	28.30%
The taxable gain percentage of capital gains deduction	50.00%
Capital Loss Carryforward [Member]
Operating Loss Carryforwards [Line Items]
Capital losses		$ 27.2
Valuation Allowance	$ 0.2	$ 27.1
Tax Credit Capital loss carry-forward indefinitely	$ 1.8