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Assets held for sale (Details) (CAD) In Thousands, unless otherwise specified | 12 Months Ended
--- | ---
Mar. 31, 2013 | Mar. 31, 2012 | Mar. 31, 2011
Long Lived Assets Held-for-sale [Line Items] |  |  |
Loss (gain) on disposal of assets held for sale | 98 | (466) | 825
Assets held for sale | 157,464 | 1,841 |
Heavy equipment |  |  |
Long Lived Assets Held-for-sale [Line Items] |  |  |
Assets held for sale | 2,724 | 1,841 |
Piling assets |  |  |
Long Lived Assets Held-for-sale [Line Items] |  |  |
Assets held for sale | 154,740 |  |
Depreciation Expense [Member] |  |  |
Long Lived Assets Held-for-sale [Line Items] |  |  |
Impairment of assets held for sale | 3,346 | 8,748 | 141

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- Definition Current assets (normally turning over within one year or one business cycle if longer) that are held for sale apart from normal operations and anticipated to be sold within one year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 205 -SubTopic 20 -Section 45 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=6892542&loc=d3e1107-107759 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 46 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + 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=6943989&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 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 144 -Paragraph 27, 28, 29, 30 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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