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Significant accounting policies (Tables) | 12 Months Ended
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Dec. 31, 2013
Accounting Policies [Abstract] |
Schedule of 100% owned subsidiaries of NACHI | These consolidated financial statements are prepared in accordance with United States generally accepted accounting principles ("US GAAP"). Material inter-company transactions and balances are eliminated upon consolidation. These consolidated financial statements include the accounts of the Company, its wholly-owned subsidiaries, NACGI, North American Fleet Company Ltd., North American Construction Holdings Inc. (“NACHI”) and NACG Properties Inc., and the following 100% owned subsidiaries of NACHI:
• North American Caisson Ltd. |  | • North American Site Development Ltd.
• North American Engineering Inc. |  | • North American Tailings and Environmental Ltd.
• North American Enterprises Ltd. |  | • Drillco Foundation Co. Ltd.
• North American Maintenance Ltd. |  | • 1565388 Alberta Ltd.
• North American Mining Inc. |  | • 1565401 Alberta Ltd.
• North American Pile Driving Inc. |  | • 1753514 Alberta Ltd.
• North American Services Inc. |  |
Schedule of depreciation of property, plant and equipment | Depreciation is calculated based on the cost, net of the estimated residual value, over the estimated useful life of the assets on the following bases and rates:
Assets |  | Basis |  | Rate
Heavy equipment |  | Straight-line |  | Operating hours
Major component parts in use |  | Straight-line |  | Operating hours
Other equipment |  | Straight-line |  | 5 – 10 years
Licensed motor vehicles |  | Straight-line |  | 5 – 10 years
Office and computer equipment |  | Straight-line |  | 4 years
Buildings |  | Straight-line |  | 10 years
Leasehold improvements |  | Straight-line |  | Over shorter of estimated useful life and lease term
December 31, 2013 |  | Cost |  |  | Accumulated Deprecation |  |  | Net Book Value |
Heavy equipment |  | $ | 251,872 |  |  | $ | 96,038 |  |  | $ | 155,834 |
Major component parts in use |  | 60,484 |  |  | 23,472 |  |  | 37,012 |
Other equipment |  | 27,594 |  |  | 11,511 |  |  | 16,083 |
Licensed motor vehicles |  | 25,911 |  |  | 22,474 |  |  | 3,437 |
Office and computer equipment |  | 13,846 |  |  | 11,882 |  |  | 1,964 |
Buildings |  | 4,691 |  |  | 2,650 |  |  | 2,041 |
Leasehold improvements |  | 9,946 |  |  | 6,187 |  |  | 3,759 |
Assets under capital lease |  | 72,627 |  |  | 14,782 |  |  | 57,845 |
|  | $ | 466,971 |  |  | $ | 188,996 |  |  | $ | 277,975 |
December 31, 2012 |  | Cost |  |  | Accumulated Deprecation |  |  | Net Book Value |
Heavy equipment |  | $ | 321,976 |  |  | $ | 113,373 |  |  | $ | 208,603 |
Major component parts in use |  | 59,538 |  |  | 22,543 |  |  | 36,995 |
Other equipment |  | 37,684 |  |  | 18,127 |  |  | 19,557 |
Licensed motor vehicles |  | 32,010 |  |  | 25,333 |  |  | 6,677 |
Office and computer equipment |  | 13,122 |  |  | 10,630 |  |  | 2,492 |
Buildings |  | 3,541 |  |  | 3,096 |  |  | 445 |
Land |  | 166 |  |  | — |  |  | 166 |
Leasehold improvements |  | 9,743 |  |  | 5,656 |  |  | 4,087 |
Assets under capital lease |  | 64,901 |  |  | 11,671 |  |  | 53,230 |
|  | $ | 542,681 |  |  | $ | 210,429 |  |  | $ | 332,252 |

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- Definition Tabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.13) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 13 -Subparagraph b -Article 5 + Details
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