Significant accounting policies - Stock-based compensation (Details) - CAD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equipment expense	$ 243,427,000	$ 129,692,000
Inventory net	$ 21,649,000	$ 13,391,000
Number of trading days used to determine weighted average trading price of common shares	5 days
Inventory Error [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Inventory gross	$ (2,775,000)
Equipment expense	(2,775)
Inventory net	2,040,000
Equipment Expense net	$ (2,040)
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ownership percentage	20.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ownership percentage	50.00%
Restricted Share Unit (RSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award service period	2 years
Award vesting period	3 years
Compensation expense recognition period	3 years
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	3 years
Compensation expense recognition period	3 years

Equipment Expense, Net

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Number of Trading Days Used to Calculate Weighted Average Trading Price of Common Stock

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- Definition

Share-based Compensation Arrangement by Share-based Payment Award, Period for Recognition

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- Definition

This element represents equipment expense including depreciation, repairs, rentals, and service contract costs. This item also includes equipment purchases which do not qualify for capitalization in accordance with the entity's accounting policy. This item may also include furniture expenses.

+ References

No definition available.

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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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- Definition

Gross amount, as of the balance sheet date, of merchandise, goods, commodities, or supplies held for future sale or to be used in manufacturing, servicing or production process.

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-SubTopic 10
-Section S99
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Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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- Definition

Estimated period over which an employee is required to provide service in exchange for the equity-based payment award, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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