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Assets held for sale (Details) (CAD) In Thousands, unless otherwise specified | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012
Long Lived Assets Held-for-sale [Line Items] |  |
Loss (gain) on disposal of assets held for sale | 2,212 | (90)
Heavy equipment |  |
Long Lived Assets Held-for-sale [Line Items] |  |
Loss (gain) on disposal of assets held for sale | 2,212 | (90)
Depreciation expense | Heavy equipment |  |
Long Lived Assets Held-for-sale [Line Items] |  |
Impairment of assets held for sale | 3,097 | 8,622

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- Definition Gain (Loss) on Disposition of Assets Held for Sale + References No definition available. + Details
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- Definition The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=8077374&loc=d3e2611-110228 + Details
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