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Income taxes - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 CAD ($) provincial_jurisdiction	Dec. 31, 2017 CAD ($) provincial_jurisdiction
Income Tax Disclosure [Abstract]
Number of provincial jurisdictions | provincial_jurisdiction	1	1
Deferred tax assets, non-capital operating loss carryforwards	$ 23,443
Non-capital losses for income tax purposes	86,826
Valuation allowance, amount	1,035	$ 1,035
Operating loss carryforwards, not subject to expiration	$ 7,664

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Number of Provincial Income Taxing Jurisdictions

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Operating Loss Carryforwards, Not Subject To Expiration

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- Definition

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards that are subject to expiration dates.

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- Definition

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 3
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