Revenue Recognition Revenue Allocated to Remaining Performance Obligations (Details) $ in Millions	Dec. 31, 2018 CAD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Eestimated revenue allocated to remaining performance obligations	$ 1,645.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue allocated to remaining performance obligations, recognition period	1 year
Eestimated revenue allocated to remaining performance obligations	$ 313.4
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue allocated to remaining performance obligations, recognition period	2 years
Eestimated revenue allocated to remaining performance obligations	$ 250.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue allocated to remaining performance obligations, recognition period	3 years
Eestimated revenue allocated to remaining performance obligations	$ 193.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue allocated to remaining performance obligations, recognition period	4 years
Eestimated revenue allocated to remaining performance obligations	$ 183.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue allocated to remaining performance obligations, recognition period	5 years
Eestimated revenue allocated to remaining performance obligations	$ 171.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Estimated revenue allocated to remaining performance obligations, recognition period	1 year
Eestimated revenue allocated to remaining performance obligations	$ 533.1