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Other assets - Intangible assets (Details) - CAD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2018 | Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items] |  |
Cost | $ 13,935 |
Accumulated Amortization | 11,019 |
Net book value | 2,916 | $ 938
Amortization of intangible assets | 412 | 918
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] |  |
2019 | 734 |
2020 | 664 |
2021 | 470 |
2022 | 439 |
2023 and thereafter | 609 |
Net book value | 2,916 | 938
Internal-use software |  |
Finite-Lived Intangible Assets [Line Items] |  |
Cost | 11,925 | 18,188
Accumulated Amortization | 11,019 | 17,250
Net book value | 906 | 938
Fully amortized intangible asset disposed during the period | 6,643 |
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] |  |
Net book value | 906 | $ 938
Other intangible assets |  |
Finite-Lived Intangible Assets [Line Items] |  |
Cost | 2,010 |
Accumulated Amortization | 0 |
Net book value | 2,010 |
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] |  |
Net book value | $ 2,010 |

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- Definition The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6388964&loc=d3e16225-109274 + Details
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