North American Construction (NOA) 40-F 17 Feb 15 2014 FY Annual report (Canada) Financial data

Document_and_Entity_Informatio

Document and Entity Information	12 Months Ended
	Dec. 31, 2014
Document and Entity Information [Abstract]
Entity Registrant Name	North American Energy Partners Inc.
Entity Central Index Key	1368519
Document Type	40-F
Document Period End Date	31-Dec-14
Amendment Flag	FALSE
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	-19
Entity Current Reporting Status	Yes
Entity Common Stock, Shares Outstanding	34,923,916

Consolidated_Balance_Sheets

Consolidated Balance Sheets (CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current assets
Cash	956	13,742
Accounts receivable, net (note 5 and 15(d))	66,503	70,177
Unbilled revenue (note 6 and 15(d))	43,622	32,168
Inventories	7,449	5,907
Prepaid expenses and deposits (note 7)	2,253	2,152
Assets held for sale (note 8 and 15(a))	29,589	52
Deferred tax assets (note 9)	5,609	3,678
Total current assets	155,981	127,876
Plant and equipment, net (note 10)	260,898	277,975
Other assets (note 11(a))	9,755	12,130
Deferred tax assets (note 9)	29,947	27,660
Total Assets	456,581	445,641
Current liabilities
Accounts payable	58,089	48,438
Accrued liabilities (note 12)	14,997	15,655
Billings in excess of costs incurred and estimated earnings on uncompleted contracts (note 6)	0	6,357
Capital Lease Obligations, Current	22,201	14,996
Deferred tax liabilities (note 9)	20,056	8,036
Total current liabilities	115,343	93,482
Long term debt (note 13(a))	64,269	75,000
Capital lease obligations (note 14)	41,854	28,299
Other long term obligations (note 16(a))	3,459	7,207
Deferred tax liabilities (note 9)	42,077	49,818
Total liabilities	267,002	253,806
Shareholders' equity
Common shares (authorized - unlimited number of voting common shares) (note 17(a))	290,800	290,517
Treasury shares (note 17(a))	-3,685	0
Additional paid-in capital	19,866	14,750
Deficit	-117,402	-113,432
Total shareholders' equity	189,579	191,835
Total liabilities and shareholders' equity	456,581	445,641
Commitments (note 18)
Contingencies (note 19)

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Common shares, authorized	unlimited	unlimited

Consolidated_Statements_of_Ope

Consolidated Statements of Operations and Comprehensive (loss) Income (CAD)	12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Revenue	471,777	470,484
Project costs	216,342	180,348
Equipment costs	161,108	207,906
Depreciation	42,927	36,491
Gross profit	51,400	45,739
General and administrative expenses	33,462	39,901
Loss on disposal of plant and equipment	2,777	3,033
(Gain) loss on disposal of assets held for sale (note 8)	-86	2,212
Amortization of intangible assets (note 11(b))	3,648	3,276
Operating income (loss) before the undernoted	11,599	-2,683
Interest expense (note 21)	12,235	21,697
Foreign exchange loss (gain)	38	-156
Unrealized gain on derivative financial instruments	0	-6,551
Loss on debt extinguishment (note 13(c))	54	6,476
Loss from continuing operations before income taxes	-728	-24,149
Income tax (note 9):
Current benefit	-92	-2,438
Deferred expense (benefit)	61	-3,664
Net loss from continuing operations	-697	-18,047
(Loss) income from discontinued operations, net of tax (note 22)	-472	87,231
Net (loss) income	-1,169	69,184
Other comprehensive income
Unrealized foreign currency translation gain	0	27
Comprehensive (loss) income	-1,169	69,211
Per share information from continuing operations
Net loss - basic (note 18) (in CAD per share)	-0.02	-0.5
Net loss - diluted (note 18) (in CAD per share)	-0.02	-0.5
Net (loss) income - basic (note 18) (in CAD per share)	-0.01	2.41
Net (loss) income - diluted (note 18) (in CAD per share)	-0.01	2.39
Net (loss) income - basic (note 18) (in CAD per share)	-0.03	1.91
Net (loss) income - diluted (note 18) (in CAD per share)	-0.03	1.89
Cash dividend per share (note 17(d))	0.08	0

Consolidated_Statements_of_Cha

Consolidated Statements of Changes in Shareholders' Equity (CAD)	Total	Common shares	Treasury shares	Additional paid-in capital	Deficit	Accumulated other comprehensive (loss) income
In Thousands, unless otherwise specified
Beginning balance at Dec. 31, 2012	132,557	304,908		10,292	-182,616	-27
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	69,184				69,184
Unrealized foreign currency translation loss	27					27
Exercised stock options	1,175	1,742		-567
Stock-based compensation	632			632
Share purchase program	-11,740	-16,133		4,393
Ending balance at Dec. 31, 2013	191,835	290,517	0	14,750	-113,432	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	-1,169				-1,169
Unrealized foreign currency translation loss	0
Exercised stock options	2,807	4,521		-1,714
Stock-based compensation	4,533			4,533
Dividends	-2,801				-2,801
Share purchase program	-1,941	-4,238		2,297
Purchase of treasury shares for settlement of certain equity classified stock-based compensation	-3,685		-3,685
Ending balance at Dec. 31, 2014	189,579	290,800	-3,685	19,866	-117,402	0

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net loss from continuing operations	-697	-18,047
Adjustments to reconcile to net cash from operating activities:
Depreciation	42,927	36,491
Amortization of intangible assets (note 11(b))	3,648	3,276
Amortization of deferred financing costs (note 11(c))	1,594	4,326
Lease inducement paid on sublease	-1,200	0
Loss on disposal of plant and equipment	2,777	3,033
(Gain) loss on disposal of assets held for sale (note 8)	-86	2,212
Unrealized gain on derivative financial instruments	0	-6,551
Loss on debt extinguishment (note 13(c))	54	6,476
Stock-based compensation expense (note 23(a))	3,305	6,193
Cash settlement of stock-based compensation (note 23(d(i)) and 23(f(i)))	-3,235	-1,695
Other adjustments to cash from operating activities (note 11(d), 16(b) and 16(c))	38	-61
Deferred income tax (benefit) (note 9)	61	-3,664
Net changes in non-cash working capital (note 24(b))	-7,485	25,499
Total operating activities	41,701	57,488
Investing activities:
Purchase of plant and equipment	-35,146	-31,351
Additions to intangible assets (note 11(b))	-990	-2,826
Proceeds on disposal of plant and equipment	15,378	3,978
Proceeds on disposal of assets held for sale	1,270	3,106
Total investing activities	-19,488	-27,093
Financing activities:
Repayment of credit facilities	-85,000	-234,684
Increase in credit facilities	90,536	172,396
Financing costs (note 11(c))	-87	-2,789
Redemption of Series 1 Debentures (note 13(c))	-16,321	-156,476
Proceeds from options exercised (note 23(b) and 23(c))	2,807	1,175
Dividend payments (note 17(d))	-2,104	0
Purchase of treasury shares for share unit settlement (note 17(a))	-3,685	0
Share purchase program (note 17(c))	-1,941	-11,740
Repayment of capital lease obligations	-18,732	-14,030
Total financing activities	-34,527	-246,148
Decrease in cash from continuing operations	-12,314	-215,753
Cash provided by (used in) discontinued operations (note 22)
Operating activities	-472	45,739
Investing activities	0	182,836
Financing activities	0	-271
Total cash provided by (used in) discontinued operations	-472	228,304
(Decrease) increase in cash	-12,786	12,551
Effect of exchange rate on changes in cash	0	27
Cash, beginning of year	13,742	1,164
Cash, end of year	956	13,742

Nature_of_operations

Nature of operations	12 Months Ended
	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of operations	Nature of operations
	North American Energy Partners Inc. (the “Company”), formerly NACG Holdings Inc., was incorporated under the Canada Business Corporations Act on October 17, 2003. On November 26, 2003, the Company purchased all the issued and outstanding shares of North American Construction Group Inc. (“NACGI”), including subsidiaries of NACGI, from Norama Ltd. which had been operating continuously in Western Canada since 1953. The Company had no operations prior to November 26, 2003. The Company provides a wide range of mining and heavy construction services to customers in the resource development and industrial construction sectors, primarily within Western Canada.

Significant_accounting_policie

Significant accounting policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant accounting policies	Significant accounting policies
	a) Basis of presentation
	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 Engineering Inc.		• North American Site Development Ltd.
	• North American Enterprises Ltd.		• North American Maintenance Ltd.
	• North American Mining Inc.		• North American Tailings and Environmental Ltd.
	• North American Services Inc.		• 1753514 Alberta Ltd.
	b) Use of estimates
	The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures reported in these consolidated financial statements and accompanying notes and the reported amounts of revenues and expenses during the reporting period.
	Significant estimates made by management include the assessment of the percentage of completion on time-and-materials, unit-price, lump-sum and cost-plus contracts with defined scope (including estimated total costs and provisions for estimated losses) and the recognition of claims and change orders on revenue contracts; assumptions used in periodic impairment testing; and, estimates and assumptions used in the determination of the allowance for doubtful accounts, the recoverability of deferred tax assets and the useful lives of property, plant and equipment and intangible assets. Actual results could differ materially from those estimates.
	The accuracy of the Company’s revenue and profit recognition in a given period is dependent on the accuracy of its estimates of the cost to complete for each project. Cost estimates for all significant projects use a detailed “bottom up” approach and the Company believes its experience allows it to provide reasonably dependable estimates. There are a number of factors that can contribute to changes in estimates of contract cost and profitability that are recognized to the extent contract remedies are unavailable in the period in which such adjustments are determined. The most significant of these include:
	•	the completeness and accuracy of the original bid;
	•	costs associated with added scope changes;
	•	extended overhead due to owner, weather and other delays;
	•	subcontractor performance issues;
	•	changes in economic indices used for the determination of escalation or de-escalation for contractual rates on long-term contracts;
	•	changes in productivity expectations;
	•	site conditions that differ from those assumed in the original bid;
	•	contract incentive and penalty provisions;
	•	the availability and skill level of workers in the geographic location of the project; and
	•	a change in the availability and proximity of equipment and materials.
	The foregoing factors as well as the mix of contracts at different margins may cause fluctuations in gross profit between periods. With many projects of varying levels of complexity and size in process at any given time, changes in estimates can offset each other without materially impacting the Company’s profitability. Major changes in cost estimates, particularly in larger, more complex projects, can have a significant effect on profitability.
	c) Revenue recognition
	The Company performs its projects under the following types of contracts: time-and-materials; cost-plus; unit-price; and lump-sum. Revenue is recognized as costs are incurred for time-and-materials, unit-price and cost-plus service contracts with no clearly defined scope. Revenue on cost-plus, unit-price, lump-sum and time-and-materials contracts with defined scope is recognized using the percentage-of-completion method, measured by the ratio of costs incurred to date to estimated total costs. The estimated total cost of the contract and percent complete is determined based upon estimates made by management. The costs of items that do not relate to performance of contracted work, particularly in the early stages of the contract, are excluded from costs incurred to date. The resulting percent complete methodology is applied to the approved contract value to determine the revenue recognized. Customer payment milestones typically occur on a periodic basis over the period of contract completion.
	The length of the Company’s contracts varies from less than one year for typical contracts to several years for certain larger contracts. Contract project costs include all direct labour, material, subcontract and equipment costs and those indirect costs related to contract performance such as indirect labour and supplies. General and administrative expenses are charged to expense as incurred. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Changes in project performance, project conditions, and estimated profitability, including those arising from contract penalty provisions and final contract settlements, may result in revisions to costs and revenue that are recognized in the period in which such adjustments are determined. Profit incentives are included in revenue when their realization is reasonably assured.
	Once a project is underway, the Company will often experience changes in conditions, client requirements, specifications, designs, materials and work schedule. Generally, a “change order” will be negotiated with the customer to modify the original contract to approve both the scope and price of the change. Occasionally, however, disagreements arise regarding changes, their nature, measurement, timing and other characteristics that impact costs and revenue under the contract. When a change becomes a point of dispute between the Company and a customer, the Company will then consider it as a claim.
	Costs related to unapproved change orders and claims are recognized when they are incurred.
	Revenues related to unapproved change orders and claims are included in total estimated contract revenue only to the extent that contract costs related to the claim have been incurred and when it is probable that the unapproved change order or claim will result in:
	•	a bona fide addition to contract value; and
	•	revenues can be reliably estimated.
	These two conditions are satisfied when:
	•	the contract or other evidence provides a legal basis for the unapproved change order or claim, or a legal opinion is obtained providing a reasonable basis to support the unapproved change order or claim;
	•	additional costs incurred were caused by unforeseen circumstances and are not the result of deficiencies in the Company’s performance;
	•	costs associated with the unapproved change order or claim are identifiable and reasonable in view of work performed; and
	•	evidence supporting the unapproved change order or claim is objective and verifiable.
	This can lead to a situation where costs are recognized in one period and revenue is recognized when customer agreement is obtained or claim resolution occurs, which can be in subsequent periods. Historical claim recoveries should not be considered indicative of future claim recoveries.
	The Company’s long term contracts typically allow its customers to unilaterally reduce or eliminate the scope of the work as contracted without cause. These long term contracts represent higher risk due to uncertainty of total contract value and estimated costs to complete; therefore, potentially impacting revenue recognition in future periods.
	A contract is regarded as substantially completed when remaining costs and potential risks are insignificant in amount.
	The Company recognizes revenue from equipment rental as performance requirements are achieved in accordance with the terms of the relevant agreement with the customer, either at a monthly fixed rate or on a usage basis dependent on the number of hours that the equipment is used. Revenue is recognized from the foregoing activity once persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, fees are fixed and determinable and collectability is reasonably assured.
	d) Balance sheet classifications
	A one-year time period is typically used as the basis for classifying current assets and liabilities. However, included in current assets and liabilities are amounts receivable and payable under construction contracts (principally holdbacks) that may extend beyond one year.
	e) Cash
	Cash includes cash on hand and bank balances net of outstanding cheques.
	f) Accounts receivable and unbilled revenue
	Accounts receivable are primarily comprised of amounts billed to clients for services already provided, but which have not yet been collected. Unbilled revenue represents revenue recognized in advance of amounts billed to clients.
	g) Billings in excess of costs incurred and estimated earnings on uncompleted contracts
	Billings in excess of costs incurred and estimated earnings on uncompleted contracts represent amounts invoiced in excess of revenue recognized.
	h) Allowance for doubtful accounts
	The Company evaluates the probability of collection of accounts receivable and records an allowance for doubtful accounts, which reduces accounts receivable to the amount management reasonably believes will be collected. In determining the amount of the allowance, the following factors are considered: the length of time the receivable has been outstanding, specific knowledge of each customer’s financial condition and historical experience.
	i) Inventories
	Inventories are carried at the lower of weighted average cost and market, and consist primarily of spare tires and tracks.
	j) Property, plant and equipment
	Property, plant and equipment are recorded at cost. Major components of heavy construction equipment in use such as engines and drive trains are recorded separately. Equipment under capital lease is recorded at the present value of minimum lease payments at the inception of the lease. Depreciation is not recorded until an asset is available for use. 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
	The costs for periodic repairs and maintenance are expensed to the extent the expenditures serve only to restore the assets to their normal operating condition without enhancing their service potential or extending their useful lives.
	k) Capitalized interest
	The Company capitalizes interest incurred on debt during the construction of assets for the Company’s own use. The capitalization period covers the duration of the activities required to get the asset ready for its intended use, provided that expenditures for the asset have been made and interest cost incurred. Interest capitalization continues as long as those activities and the incurrence of interest cost continue. The capitalized interest is amortized at the same rate as the respective asset.
l) Intangible assets
Intangible assets include capitalized computer software and development costs, which are being amortized on a straight-line basis over a maximum period of four years.
The Company expenses or capitalizes costs associated with the development of internal-use software as follows:
•	Preliminary project stage: Both internal and external costs incurred during this stage are expensed as incurred.
•	Application development stage: Both internal and external costs incurred to purchase and develop computer software are capitalized after the preliminary project stage is completed and management authorizes the computer software project. However, training costs and the costs incurred for the process of data conversion from the old system to the new system, which includes purging or cleansing of existing data, reconciliation or balancing of old data to the converted data in the new system, are expensed as incurred.
•	Post implementation/operation stage: All training costs and maintenance costs incurred during this stage are expensed as incurred.
Costs of upgrades and enhancements are capitalized if the expenditures will result in adding functionality to the software.
m) Impairment of long-lived assets
Long-lived assets or asset groups held and used including plant, equipment and identifiable intangible assets subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the undiscounted future cash flows expected to result from the use and eventual disposition of an asset or group of assets is less than its carrying amount, it is considered to be impaired. The Company measures the impairment loss as the amount by which the carrying amount of the asset or group of assets exceeds its fair value, which is charged to depreciation or amortization expense. In determining whether an impairment exists, the Company makes assumptions about the future cash flows expected from the use of its long-lived assets, such as: applicable industry performance and prospects; general business and economic conditions that prevail and are expected to prevail; expected growth; maintaining its customer base; and, achieving cost reductions. There can be no assurance that expected future cash flows will be realized, or will be sufficient to recover the carrying amount of long-lived assets. Furthermore, the process of determining fair values is subjective and requires management to exercise judgment in making assumptions about future results, including revenue and cash flow projections and discount rates.
n) Assets held for sale
Long-lived assets are classified as held for sale when certain criteria are met, which include:
•	management, having the authority to approve the action, commits to a plan to sell the assets;
•	the assets are available for immediate sale in their present condition;
•	an active program to locate buyers and other actions to sell the assets have been initiated;
•	the sale of the assets is probable and their transfer is expected to qualify for recognition as a completed sale within one year;
•	the assets are being actively marketed at reasonable prices in relation to their fair value; and
•	it is unlikely that significant changes will be made to the plan to sell the assets or that the plan will be withdrawn.
Assets to be disposed of by sale are reported at the lower of their carrying amount or estimated fair value less costs to sell and are disclosed separately on the Consolidated Balance Sheets. These assets are not depreciated.
o) Asset retirement obligations
Asset retirement obligations are legal obligations associated with the retirement of property, plant and equipment that result from their acquisition, lease, construction, development or normal operations. The Company recognizes its contractual obligations for the retirement of certain tangible long-lived assets. The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The fair value of a liability for an asset retirement obligation is the amount at which that liability could be settled in a current transaction between willing parties, that is, other than in a forced or liquidation transaction and, in the absence of observable market transactions, is determined as the present value of expected cash flows. The associated asset retirement costs are capitalized as part of the carrying amount of the long-lived asset and then amortized using a systematic and rational method over its estimated useful life. In subsequent reporting periods, the liability is adjusted for the passage of time through an accretion charge and any changes in the amount or timing of the underlying future cash flows are recognized as an additional asset retirement cost.
p) Foreign currency translation
The functional currency of the Company its subsidiaries is Canadian Dollars. Transactions denominated in foreign currencies are recorded at the rate of exchange on the transaction date. Monetary assets and liabilities, denominated in foreign currencies, are translated into Canadian Dollars at the rate of exchange prevailing at the balance sheet date. Foreign exchange gains and losses are included in the determination of earnings.
q) Fair value measurement
Fair value measurements are categorized using a valuation hierarchy for disclosure of the inputs used to measure fair value, which prioritizes the inputs into three broad levels. Fair values included in Level 1 are determined by reference to quoted prices in active markets for identical assets and liabilities. Fair values included in Level 2 include valuations using inputs based on observable market data, either directly or indirectly other than the quoted prices. Level 3 valuations are based on inputs that are not based on observable market data. The classification of a fair value within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.
r) Derivative financial instruments
The Company used derivative financial instruments to manage financial risks from fluctuations in exchange rates. These instruments included embedded price escalation features in supplier contracts. Such instruments were only used for risk management purposes. The Company does not hold or issue derivative financial instruments for trading or speculative purposes. Derivative financial instruments are subject to standard terms and conditions, financial controls, management and risk monitoring procedures. These derivative financial instruments were not designated as hedges for accounting purposes and were recorded at fair value with realized and unrealized gains and losses recognized in the Consolidated Statements of Operations.
s) Income taxes
The Company uses the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rates is recognized in income in the period of enactment. The Company recognizes the effect of income tax positions only if those positions are more likely than not (greater than 50%) of being sustained. Changes in recognition or measurement are reflected in the period in which the change in judgement occurs. The Company accrues interest and penalties for uncertain tax positions in the period in which these uncertainties are identified. Interest and penalties are included in “General and administrative expenses” in the Consolidated Statements of Operations. A valuation allowance is recorded against any deferred tax asset if it is more likely than not that the asset will not be realized.
t) Stock-based compensation
The Company has a Share Option Plan which is described in note 23(b). The Company accounts for all stock-based compensation payments that are settled by the issuance of equity instruments at fair value. Compensation cost is measured using the Black-Scholes model at the grant date and is expensed on a straight-line basis over the award’s vesting period, with a corresponding increase to additional paid-in capital. Upon exercise of a stock option, share capital is recorded at the sum of proceeds received and the related amount of additional paid-in capital.
The Company has a Senior Executive Stock Option Plan which is described in note 23(c). This compensation plan allows the option holder the right to settle options in cash. The liability is measured at fair value using the Black-Scholes model at the modification date and subsequently at each period end date. Changes in fair value of the liability are recognized in the Consolidated Statements of Operations when the period end fair value exceeds the fair value at the modification date and in the Consolidated Balance Sheets when the period end fair value is less than the fair value at the modification date.
The Company has a Restricted Share Unit (“RSU”) Plan which is described in note 23(d). RSUs are granted effective April 1 of each fiscal year with respect to services to be provided in that fiscal year and the following two fiscal years. The RSUs generally vest at the end of the three-year term. When dividends are paid on common shares, additional dividend equivalent RSUs are granted to all RSU holders as of the dividend payment date. The number of additional RSUs to be granted is determined by multiplying the dividend payment per common share by the number of outstanding RSUs, divided by the fair market value of the Company's common shares on the dividend payment date. Such additional RSUs are granted subject to the same service criteria as the underlying RSUs. The Company settles all RSUs issued after February 19, 2014, with common shares purchased on the open market through a trust arrangement ("equity classified RSUs"). The Company will continue to settle the existing RSUs with cash ("liability classified RSUs"). Compensation expense is calculated based on the number of vested RSUs multiplied by the fair market value of each RSU as determined by the volume weighted average trading price of the Company’s common shares for the five trading days immediately preceding the day on which the fair market value is to be determined. The Company recognizes compensation cost over the three-year term of the RSU in the Consolidated Statements of Operations, with a corresponding increase to liability for the liability classified RSUs and additional paid-in capital for the equity classified RSUs. When dividends are paid on common shares, additional dividend equivalent RSUs are granted to all RSU holders as of the dividend payment date. The number of additional RSUs to be granted is determined by multiplying the dividend payment per common share by the number of outstanding RSUs, divided by the fair market value of the Company's common shares on the dividend payment date. Such additional RSUs are granted subject to the same service criteria as the underlying RSUs.
The Company has a Performance restricted share unit ("PSU") plan which is described in note 23(e). The PSUs vest at the end of a three-year term and are subject to the performance criteria approved by the Human Resources and Compensation Committee at the date of the grant. Such performance criterion includes the passage of time and is based upon the improvement of total shareholder return ("TSR") as compared to a defined company Canadian peer group. TSR is calculated using the fair market values of voting common shares at the grant date, the fair market value of voting common shares at the vesting date and the total dividends declared and paid throughout the vesting period. At the maturity date, the Human Resources and Compensation Committee will assess actual performance against the performance criteria and determine the number of PSUs that have been earned. The company intends to settle all PSUs with common shares purchased on the open market through a trust arrangement. The Company recognizes compensation cost over the three-year term of the PSU in the Consolidated Statement of Operations, with a corresponding increase to liability.
The Company has a Deferred Stock Unit (“DSU”) Plan which is described in note 23(f). Prior to the year ended December 31, 2014, this plan was referred to as the Directors Deferred Share Unit ("DDSU") Plan as only directors were awarded under it. During the year ended December 31, 2014, the plan was modified to include executives and has since been referred to as the DSU plan. The DSU plan enables directors and executives to receive all or a portion of their annual fee or annual executive bonus compensation in the form of DSUs. The DSUs issued prior to February 19, 2014, are settled in cash ("liability classified DSUs") and all DSUs and dividend equivalents issued after this date are settled in common shares ("equity classified DSUs") purchased on the open market through a defined trust arrangement. Compensation expense is calculated based on the number of DSUs multiplied by the fair market value of each DSU as determined by the volume weighted average trading price of the Company’s common shares for the five trading days immediately preceding the day on which the fair market value is to be determined, with a corresponding increase to liability for the liability classified DSUs and additional paid-in capital for the equity classified DSUs. Compensation costs related to DSUs are recognized in full upon the grant date as the units vest immediately. When dividends are paid on common shares, additional dividend equivalent DSUs are granted to all DSU holders as of the dividend payment date. The number of additional DSUs to be granted is determined by multiplying the dividend payment per common share by the number of outstanding DSUs, divided by the fair market value of the Company's common shares on the dividend payment date. Such additional DSUs are granted subject to the same service criteria as the underlying DSUs.
u) Net income (loss) per share
Basic net income (loss) per share is computed by dividing net income (loss) available to common shareholders by the weighted average number of shares outstanding during the year (see note 17(b)). Diluted per share amounts are calculated using the treasury stock method. The treasury stock method increases the diluted weighted average shares outstanding to include additional shares from the assumed exercise of stock options, if dilutive. The number of additional shares is calculated by assuming outstanding in-the-money stock options were exercised and the proceeds from such exercises, including any unamortized stock-based compensation cost, were used to acquire shares of common stock at the average market price during the year.
v) Leases
Leases entered into by the Company in which substantially all the benefits and risks of ownership are transferred to the Company are recorded as obligations under capital leases and under the corresponding category of property, plant and equipment. Obligations under capital leases reflect the present value of future lease payments, discounted at an appropriate interest rate, and are reduced by rental payments net of imputed interest. All other leases are classified as operating leases and leasing costs, including any rent holidays, leasehold incentives, and rent concessions, are amortized on a straight-line basis over the lease term.
Certain operating lease and rental agreements provide a maximum hourly usage limit, above which the Company will be required to pay for the over hour usage as a contingent rent expense. These contingent expenses are recognized when the likelihood of exceeding the usage limit is considered probable and are due at the end of the lease term or rental period. The contingent rental expenses are included in “Equipment operating lease expense” in the Consolidated Statements of Operations.
w) Deferred financing costs
Underwriting, legal and other direct costs incurred in connection with the issuance of debt not measured under the fair value option are presented as deferred financing costs. The deferred financing costs related to the Debentures and the Revolving and Term Facilities are amortized over the term of the related debt using the effective interest method.
x) Business combinations
The Company accounts for all business combinations using the acquisition method. Acquisition related costs which include finder’s fees, advisory, legal, accounting, valuation, other professional or consulting fees, and administrative costs are expensed as incurred.
y) Discontinued operations
In prior years the Company divested certain of its business operations. These businesses are presented as discontinued operations in the Company's Consolidated Statement of Operations and Comprehensive (Loss) Income and, collectively, are included in the line item "(Loss) income from discontinued operations, net of tax" for all periods presented. The cash flows from discontinued operations are included in the "Cash (used in) provided by discontinued operations" section of the Consolidated Statement of Cash Flows for all periods presented. The Company allocates interest expense incurred on debt that is required to be repaid as a result of the disposal transaction to discontinued operations. The allocation to discontinued operations of other consolidated interest that is not directly attributable to or related to other operations of the Company is allocated based on a ratio of net assets to be sold to total consolidated net assets.

Accounting_pronouncements_rece

Accounting pronouncements recently adopted	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
Accounting pronouncements recently adopted	Accounting pronouncements recently adopted
	a) Income Taxes
	In July 2013, the Financial Accounting Standards Board ("FASB") issued Accounting Standard Update ("ASU") No. 2013-11, Income Taxes (Topic 740): Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carry Forward Exists. This accounting standard eliminates the diversity in practice in the presentation of unrecognized tax benefits. The amendments in this ASU provide guidance on the financial statement presentation of an unrecognized tax benefit when a net operating loss carry forward, similar tax loss, or tax credit carry forward exists. The Company adopted this ASU effective January 1, 2014. The adoption of this standard did not have a material effect on the Company's consolidated financial statements.

Recent_accounting_pronouncemen

Recent accounting pronouncements not yet adopted	12 Months Ended
	Dec. 31, 2014
Accounting Changes and Error Corrections [Abstract]
Recent accounting pronouncements not yet adopted	Recent accounting pronouncements not yet adopted
	a) Presentation of financial statements and property, plant and equipment
	In April 2014, the FASB issued ASU No. 2014-08, Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disposals of Components of an Entity. This accounting standard changes the requirements for reporting discontinued operations. The amendments in this ASU change the definition of what will be reported as a discontinued operation by limiting discontinued operations to disposals of components of an entity that will have a major effect on an entities operations and financial results. This ASU will be effective for disposals recorded on or after January 1, 2015. The adoption of this standard is not expected to have a material effect on the Company's consolidated financial statements.
	b) Revenue from contracts with customers
	In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). This accounting standard updates the revenue recognition guidance to require that entities recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. The ASU provides specific steps that entities should apply to recognize revenue. This ASU will be effective commencing January 1, 2017. The Company is currently assessing the effect the adoption of this standard will have on its consolidated financial statements.
	c) Compensation - Stock Compensation
	In May 2014, the FASB issued ASU No. 2014-12, Compensation-Stock Compensation (Topic 718): Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period. This accounting standard update requires that performance targets affecting vesting of stock awards which could be achieved after the requisite service period be treated as a performance condition. Currently, US GAAP does not provide specific guidance regarding treatment of performance targets that could be achieved after the service period. This ASU will be effective commencing January 1, 2016, with early adoption permitted. The adoption of this standard is not expected to have a material effect on the Company's consolidated financial statements.
	d) Presentation of Financial Statements - Going Concern
	In August 2014, the FASB issued ASU No. 2014-15, Presentation of Financial Statements—Going Concern (Subtopic 205-40). This accounting standard provides guidance on the responsibility of management in evaluating whether there is doubt about the Company's ability to continue as a going concern. For every reporting period, management will be required to complete an evaluation on whether there is substantial doubt about the Company's ability to continue as a going concern within one year from the date of the financial statement issuance. Guidance is also provided on related note disclosure should substantial doubt be raised. This ASU will be effective commencing January 1, 2017, with early adoption permitted. The adoption of this standard is not expected to have a material effect on the Company's consolidated financial statements.

Accounts_receivable

Accounts receivable	12 Months Ended
	Dec. 31, 2014
Receivables [Abstract]
Accounts receivable	Accounts receivable
		December 31, 2014		December 31, 2013
	Accounts receivable – trade	$	54,733	$	59,309
	Accounts receivable – holdbacks	10,741		9,055
	Accounts receivable – other	1,029		1,813
	Allowance for doubtful accounts (note 15(d))	—		—
		$	66,503	$	70,177
	Accounts receivable – holdbacks represent amounts up to 10% of the contract value under certain contracts that the customer is contractually entitled to withhold until completion of the project or until certain project milestones are achieved.

Costs_incurred_and_estimated_e

Costs incurred and estimated earnings net of billings on uncompleted contracts	12 Months Ended
	Dec. 31, 2014
Contractors [Abstract]
Costs incurred and estimated earnings net of billings on uncompleted contracts	Costs incurred and estimated earnings net of billings on uncompleted contracts
		December 31, 2014			December 31, 2013
	Costs incurred and estimated earnings on uncompleted contracts	$	629,416		$	533,837
	Less billings to date	(585,794		)	(508,026		)
		$	43,622		$	25,811
	Costs incurred and estimated earnings net of billings on uncompleted contracts is presented in the Consolidated Balance Sheets under the following captions:
		December 31, 2014			December 31, 2013
	Unbilled revenue	$	43,622		$	32,168
	Billings in excess of costs incurred and estimated earnings on uncompleted contracts	—			(6,357		)
		$	43,622		$	25,811

Prepaid_expenses_and_deposits

Prepaid expenses and deposits	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid expenses and deposits	Prepaid expenses and deposits
	Current:
		December 31, 2014		December 31, 2013
	Prepaid insurance and deposits	$	968	$	1,076
	Prepaid lease payments	537		880
	Prepaid interest	748		196
		$	2,253	$	2,152
	Long term:
		December 31, 2014		December 31, 2013
	Prepaid lease payments (note 11(a))	$	1,953	$	1,274

Assets_held_for_sale

Assets held for sale	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Assets held for sale	Assets held for sale
	Equipment disposal decisions are made using an approach in which a target life is set for each type of equipment. The target life is based on the manufacturer’s recommendations and the Company’s past experience in the various operating environments. Once a piece of equipment reaches its target life it is evaluated to determine if disposal is warranted based on its expected operating cost and reliability in its current state. If the expected operating cost exceeds the target operating cost for the fleet or if the expected reliability is lower than the target reliability of the fleet, the unit is considered for disposal. Expected operating costs and reliability are based on the past history of the unit and experience in the various operating environments.
	Included in assets held for sale at December 31, 2014 were contract-specific equipment with a carrying value of $29,400 which were sold to a long-term customer subsequent to the period end on January 2, 2015 (note 20).
	During the year ended December 31, 2014, impairment of assets held for sale amounting to $3,461 has been included in depreciation expense in the Consolidated Statements of Operations (2013 – $3,097). The write-down is the amount by which the carrying value of the related assets exceeded their fair value less costs to sell. The gain on disposal of assets held for sale was $86 for the year ended December 31, 2014 (2013 – loss of $2,212).

Income_taxes

Income taxes	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income taxes	Income taxes
	Income tax provision differs from the amount that would be computed by applying the Federal and Provincial statutory income tax rates to income before income taxes. The reasons for the differences are as follows:
	Year ended December 31,	2014			2013
	Loss before income taxes	$	(728	)	$	(24,149	)
	Tax rate	25.26		%	25.26		%
	Expected benefit	$	(184	)	$	(6,101	)
	(Decrease) increase related to:
	Impact of enacted future statutory income tax rates	—			(209		)
	Income tax adjustments and reassessments	(68		)	(249		)
	Non deductible portion of capital losses	(72		)	69
	Stock-based compensation	232			315
	Other	61			73
	Income tax benefit	$	(31	)	$	(6,102	)
	Classified as:
	Year ended December 31,	2014			2013
	Current income tax (benefit) expense	$	(92	)	$	(2,438	)
	Deferred income tax benefit	61			(3,664		)
		$	(31	)	$	(6,102	)
	The deferred tax assets and liabilities are summarized below:
		December 31, 2014			December 31, 2013
	Deferred tax assets:
	Non-capital losses	$	31,151		$	39,604
	Deferred financing costs	1,135			1,709
	Billings in excess of costs on uncompleted contracts	—			1,606
	Capital lease obligations	16,148			10,914
	Deferred lease inducements	64			91
	Stock-based compensation	1,666			1,880
	Other	481			409
		$	50,645		$	56,213
		December 31, 2014			December 31, 2013
	Deferred tax liabilities:
	Unbilled revenue and uncertified revenue included in accounts receivable	$	9,538		$	5,338
	Assets held for sale	6,466			13
	Accounts receivable – holdbacks	3,084			2,308
	Property, plant and equipment	58,134			56,945
	Deferred partnership income	—			18,125
		$	77,222		$	82,729
	Net deferred income tax liability	$	(26,577	)	$	(26,516	)
	Classified as:
		December 31, 2014			December 31, 2013
	Current asset	$	5,609		$	3,678
	Long term asset	29,947			27,660
	Current liability	(20,056		)	(8,036		)
	Long term liability	(42,077		)	(49,818		)
		$	(26,577	)	$	(26,516	)
	The Company and its subsidiaries file income tax returns in the Canadian federal jurisdiction and three provincial jurisdictions. Prior to the sale of piling assets and liabilities (note 22), the Company filed income tax returns in two additional provincial jurisdictions, the US federal and Indiana, Oklahoma and Texas state jurisdictions and Columbia. The Company has substantially concluded on Canadian federal and provincial income tax matters for the years through 2009. Substantially all material US Federal and state matters have been concluded for the years through 2007.
	The Company has a full valuation allowance against capital losses in deferred tax assets of $962 as at December 31, 2014 (2013 – $962). At December 31, 2014, the Company has non-capital losses for income tax purposes of $123,307 which predominately expire after 2026 as follows:
		31-Dec-14
	2026	$	283
	2027	—
	2028	—
	2029	1
	2030	5,334
	2031	18,567
	2032	48,910
	2033	34,788
	2034	15,424
		$	123,307

Plant_and_equipment

Plant and equipment	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
Plant and equipment	Plant and equipment
	December 31, 2014	Cost		Accumulated		Net Book Value
				Deprecation
	Heavy equipment	$	142,052	$	42,292	$	99,760
	Major component parts in use	112,645		55,895		56,750
	Other equipment	41,739		18,758		22,981
	Licensed motor vehicles	24,247		20,763		3,484
	Office and computer equipment	9,355		8,216		1,139
	Buildings	2,791		2,606		185
	Assets under capital lease	101,606		25,007		76,599
		$	434,435	$	173,537	$	260,898
	December 31, 2013	Cost		Accumulated		Net Book Value
				Deprecation
	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
	Assets under capital lease are comprised predominately of heavy equipment and licensed motor vehicles.
	During the year ended December 31, 2014, additions to plant and equipment included $39,492 of assets that were acquired by means of capital leases (2013 – $13,812). Depreciation of equipment under capital lease of $12,108 (2013 – $6,694) was included in depreciation expense in the current year.

Other_assets

Other assets	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other assets	Other assets
	a) Other assets are as follows:
		December 31, 2014			December 31, 2013
	Prepaid lease payments (note 7)	$	1,953		$	1,274
	Intangible assets (note 11(b))	4,385			7,043
	Deferred financing costs (note 11(c))	2,205			3,813
	Deferred lease inducement asset (note 11(d))	1,212			—
		$	9,755		$	12,130
	b) Intangible assets
		December 31, 2014			December 31, 2013
	Cost	$	17,102		$	22,713
	Accumulated amortization	12,717			15,670
	Net book value	$	4,385		$	7,043
	During the year ended December 31, 2014, the Company capitalized $990 (2013 – $2,826) of internally developed computer software costs. During the year ended December 31, 2014, internal-use software with a cost and accumulated amortization of $6,601 (2013 - $nil) was disposed of at zero net book value.
	Amortization of intangible assets for the year ended December 31, 2014 was $3,648 (2013 – $3,276). The estimated amortization expense for future years is as follows:
	For the year ending December 31,
	2015	$	1,815
	2016	1,410
	2017	781
	2018	379
		$	4,385
	c) Deferred financing costs
	31-Dec-14	Cost			Accumulated		Net Book Value
					Amortization
	Credit Facility	$	6,878		$	6,347	$	531
	Series 1 Debentures	8,644			6,970		1,674
		$	15,522		$	13,317	$	2,205
	31-Dec-13	Cost			Accumulated		Net Book Value
					Amortization
	Credit Facility	$	6,881		$	5,994	$	887
	Series 1 Debentures	8,655			5,729		2,926
		$	15,536		$	11,723	$	3,813
	During the year ended December 31, 2014, financing fees of $87 were incurred in connection with modifications made to the Credit Facility (2013 – $1,020) (note 13(b)) and a $90 change in estimated financing fees related to the prior year was recorded. During the year ended December 31, 2014, financing fees of $nil were incurred in connection with the Series 1 Debentures (2013 – $1,769) (note 13(c)) and a $11 change in estimated financing fees related to the prior year was recorded. These fees have been recorded as deferred financing costs and are being amortized using the effective interest method over the term of the Credit Facility and the Series 1 Debentures, respectively.
	Amortization of deferred financing costs included in interest expense for the year ended December 31, 2014 was $1,594 (2013 – $4,326) (note 21). Upon the partial redemption of the Series 1 Debentures occurring during the year ended December 31, 2014, a portion of the unamortized deferred financing costs related to the redeemed Series 1 Debentures of $534 (2013 - $2,737) were expensed and included in amortization of deferred financing costs (note 11(c)).
	d) Deferred lease inducements asset
	Lease inducements applicable to lease contracts are deferred and amortized as an increase in general and administrative expenses on a straight-line basis over the lease term, which includes the initial lease term and renewal periods only where renewal is determined to be reasonably assured.
		31-Dec-14			31-Dec-13
	Balance, beginning of year	$	—		$	—
	Additions	1,307			—
	Amortization of deferred lease inducements	(95		)	—
	Balance, end of year	$	1,212		$	—

Accrued_liabilities

Accrued liabilities	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued liabilities	Accrued liabilities
		31-Dec-14		31-Dec-13
	Accrued interest payable	$	1,514	$	1,836
	Payroll liabilities	9,845		11,970
	Liabilities related to equipment leases	786		190
	Current portion of deferred gain on sale leaseback (note 16(d))	93		—
	Dividends payable (note 17(d))	697		—
	Income and other taxes payable	2,062		1,659
		$	14,997	$	15,655

Long_term_debt

Long term debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Long term debt	Long term debt
	a) Long term debt is as follows:
		December 31, 2014		December 31, 2013
	Credit Facility (note 13(b))	$	5,536	$	—
	Series 1 Debentures (note 13(c))	58,733		75,000
		$	64,269	$	75,000
	b) Credit Facility
	On September 10, 2014, the Company entered into a First Amending Agreement to the Fifth Amended and Restated Credit Agreement (the "Credit Facility"). The Fifth Amended and Restated Credit Facility was dated October 9, 2013 and expires on September 30, 2016. The Credit Facility is secured through a combination of working capital and equipment and it provides a borrowing base, determined by the value of receivables and equipment, with Senior Leverage Ratio and a Fixed Charge Cover Ratio financial covenants. Under the terms of the amended agreement, the Senior Leverage Ratio covenant of Senior Debt to Consolidated EBITDA was modified from less than 2.00 times to 1.00 to less than 2.50 times to 1.00; the permitted capital lease debt was increased by $15.0 million to $90.0 million and the Company received pre-approval to redeem up to $20.0 million of the Series 1 Debentures. As at December 31, 2014, the Company was in compliance with the covenants.
	The Credit Facility allows borrowing of up to $85.0 million broken into two tranches, contingent upon the value of the borrowing base. Tranche A supports both borrowing under the revolving facility and letters of credit up to $60.0 million and Tranche B allows up to $25.0 million in letters of credit.
	As of December 31, 2014, there was $5.5 million (December 31, 2013 - $nil) drawn against the revolving facility under Tranche A of the Credit Facility and there was $5.1 million (December 31, 2013 - $3.1 million) of issued and undrawn letters of credit under Tranche B of the Credit Facility. The December 31, 2014 borrowing base allowed for a maximum draw of the full $85.0 million between the two tranches. At December 31, 2014, the Company's unused borrowing availability under the revolving facility was $54.5 million (December 31, 2013 - $60.0 million).
	Interest on Canadian prime rate loans is paid at variable rates based on the Canadian prime rate plus the applicable pricing margin (as defined in the credit agreement). Interest on US base rate loans is paid at a rate per annum equal to the US base rate plus the applicable pricing margin. Interest on Canadian prime rate and US base rate loans is payable monthly in arrears. Stamping fees and interest related to the issuance of Bankers’ Acceptances is paid in advance upon the issuance of such Bankers’ Acceptance.
	c) Series 1 Debentures
	On April 7, 2010, the Company issued $225.0 million of 9.125% Series 1 Debentures (the “Series 1 Debentures”). The Series 1 Debentures mature on April 7, 2017. The Series 1 Debentures bear interest at 9.125% per annum, payable in equal instalments semi-annually in arrears on April 7 and October 7 in each year.
	The Series 1 Debentures are unsecured senior obligations and rank equally with all other existing and future unsecured senior debt and senior to any subordinated debt that may be issued by the Company or any of its subsidiaries. The Series 1 Debentures are effectively subordinated to all secured debt to the extent of collateral on such debt.
	The Series 1 Debentures are redeemable at the option of the Company, in whole or in part, at any time on or after: April 7, 2014 at 103.042% of the principal amount; April 7, 2015 at 101.520% of the principal amount; April 7, 2016 and thereafter at 100% of the principal amount; plus, in each case, interest accrued to the redemption date.
	If a change of control occurs, the Company is required to offer to purchase all or a portion of each debenture holder’s Series 1 Debentures, at a purchase price in cash equal to 101% of the principal amount of the Series 1 Debentures offered for repurchase plus accrued interest to the date of purchase.
	On February 28, 2014, the Company announced that it elected to redeem $10.0 million of the Series 1 Debentures. Holders of record at the close of business on April 4, 2014 had their Series 1 Debentures redeemed on a pro rata basis for 103.042% of the principal amount, plus accrued and unpaid interest. On April 8, 2014, the Company redeemed $10.0 million of aggregate principal amount of notes and recorded a premium on redemption of $0.3 million to loss on debt extinguishment. On December 22, 2014, the Company announced that it redeemed $6.3 million of the Series 1 Debentures at a price of $960 per $1,000 principal amount of the Series 1 Debentures. The Company paid $0.1 million in accrued and unpaid interest and recorded a discount on redemption of $0.3 million to loss on debt extinguishment. In the prior year, the Company redeemed $150.0 million of the Series 1 Debentures, paid $5.3 million in accrued and unpaid interest and recorded a loss on debt extinguishment of $6.5 million.

Capital_lease_obligations

Capital lease obligations	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Capital lease obligations	Capital lease obligations
	The Company’s capital leases primarily relate to heavy equipment and licensed motor vehicles. The minimum lease payments due in each of the next five fiscal years are as follows:
	2015	$	25,115
	2016	21,149
	2017	11,662
	2018	10,179
	2019	1,778
	Subtotal:	$	69,883
	Less: amount representing interest	(5,828		)
	Present value of minimum lease payments	$	64,055
	Less: current portion	(22,201		)
	Long term portion	$	41,854

Financial_instruments_and_risk

Financial instruments and risk management	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Financial instruments and risk management	Financial instruments and risk management
	In determining the fair value of financial instruments, the Company uses a variety of methods and assumptions that are based on market conditions and risks existing on each reporting date. Standard market conventions and techniques, such as discounted cash flow analysis and option pricing models, are used to determine the fair value of the Company’s financial instruments, including derivatives. All methods of fair value measurement result in a general approximation of value and such value may never actually be realized.
	The fair values of the Company’s cash, accounts receivable, unbilled revenue, accounts payable and accrued liabilities approximate their carrying amounts due to the relatively short periods to maturity for the instruments.
	The fair values of amounts due under the Credit Facility are based on management estimates which are determined by discounting cash flows required under the instruments at the interest rate currently estimated to be available for instruments with similar terms. Based on these estimates, and by using the outstanding balance of $5.5 million at December 31, 2014 and $nil at December 31, 2013 (note 13(b)), the fair value of amounts due under the Credit Facility as at December 31, 2014 and December 31, 2013 are not significantly different than their carrying value.
	Financial instruments with carrying amounts that differ from their fair values are as follows:
			31-Dec-14							31-Dec-13
			Carrying				Fair			Carrying		Fair
			Amount				Value			Amount		Value
	Capital lease obligations (i)		$	64,055			$	58,951		$	43,295	$	39,508
	Series 1 Debentures (ii)		58,733				58,733			75,000		77,813
	(i)	The fair values of amounts due under capital leases are based on management estimates which are determined by discounting cash flows required under the instruments at the interest rates currently estimated to be available for instruments with similar terms.
	(ii)	The fair value of the Series 1 Debentures is based upon the expected discounted cash flows and the period end market price of similar financial instruments.
	a) Fair value measurements
	The Company has segregated all financial assets and financial liabilities that are measured at fair value on a recurring basis into the most appropriate level within the fair value hierarchy based on the inputs used to determine the fair value at the measurement date.
	At December 31, 2014 and December 31, 2013, the Company had no financial assets or financial liabilities measured at fair value on a recurring basis which were classified as Level 1 or Level 2 under the fair value hierarchy. Non-financial assets measured at fair value on a non-recurring basis as at December 31, 2014 and December 31, 2013 in the financial statements are summarized below:
			31-Dec-14							31-Dec-13
			Carrying Amount				Change in Fair Value			Carrying Amount		Change in Fair Value
	Assets held for sale		$	29,589			$	(3,461	)	$	52	$	(3,097	)
	Assets held for sale are reported at the lower of their carrying amount or fair value less cost to sell. The fair value less cost to sell of equipment assets held for sale (note 8) is determined internally by analyzing recent auction prices for equipment with similar specifications and hours used, the residual value of the asset and the useful life of the asset. The fair value of the equipment assets held for sale are classified under Level 3 of the fair value hierarchy.
	b) Risk Management
	The Company is exposed to market and credit risks associated with its financial instruments. The Company will from time to time use various financial instruments to reduce market risk exposures from changes in foreign currency exchange rates and interest rates. The Company does not hold or use any derivative instruments for trading or speculative purposes.
	Overall, the Company’s Board of Directors has responsibility for the establishment and approval of the Company’s risk management policies. Management performs a risk assessment on a continual basis to help ensure that all significant risks related to the Company and its operations have been reviewed and assessed to reflect changes in market conditions and the Company’s operating activities.
	c) Market Risk
	Market risk is the risk that the future revenue or operating expense related cash flows, the fair value or future cash flows of a financial instrument will fluctuate because of changes in market prices such as foreign currency exchange rates and interest rates. The level of market risk to which the Company is exposed at any point in time varies depending on market conditions, expectations of future price or market rate movements and composition of the Company’s financial assets and liabilities held, non-trading physical assets and contract portfolios.
	To manage the exposure related to changes in market risk, the Company has used various risk management techniques including the use of derivative instruments. Such instruments may be used to establish a fixed price for a commodity, an interest bearing obligation or a cash flow denominated in a foreign currency.
	The sensitivities provided below are hypothetical and should not be considered to be predictive of future performance or indicative of earnings on these contracts.
	i) Foreign exchange risk
	The Company regularly transacts in foreign currencies when purchasing equipment and spare parts as well as certain general and administrative goods and services. These exposures are generally of a short-term nature and the impact of changes in exchange rates has not been significant in the past. The Company may fix its exposure in either the Canadian Dollar or the US Dollar for these short term transactions, if material.
	ii) Interest rate risk
	The Company is exposed to interest rate risk from the possibility that changes in interest rates will affect future cash flows or the fair values of its financial instruments. Interest expense on borrowings with floating interest rates, including the Company’s Credit Facility, varies as market interest rates change. At December 31, 2014, the Company held $5.5 million of floating rate debt pertaining to its Credit Facility (December 31, 2013 – $nil). As at December 31, 2014, holding all other variables constant, a 100 basis point change to interest rates on floating rate debt will result in $0.1 million corresponding change in annual interest expense. This assumes that the amount of floating rate debt remains unchanged from that which was held at December 31, 2014.
	The fair value of financial instruments with fixed interest rates, such as the Company’s Series 1 Debentures, fluctuate with changes in market interest rates. However, these fluctuations do not affect earnings, as the Company’s debt is carried at amortized cost and the carrying value does not change as interest rates change.
	The Company manages its interest rate risk exposure by using a mix of fixed and variable rate debt and may use derivative instruments to achieve the desired proportion of variable to fixed-rate debt.
	d) Credit Risk
	Credit risk is the risk that financial loss to the Company may be incurred if a customer or counterparty to a financial instrument fails to meet its contractual obligations. The Company manages the credit risk associated with its cash by holding its funds with what it believes to be reputable financial institutions. The Company is also exposed to credit risk through its accounts receivable and unbilled revenue. Credit risk for trade and other accounts receivables, and unbilled revenue are managed through established credit monitoring activities.
	The Company has a concentration of customers in the oil and gas sector. The following customers accounted for 10% or more of total revenues:
	Year ended December 31,		2014			2013
	Customer A		29	%		—	%
	Customer B		28	%		29	%
	Customer C		14	%		22	%
	Customer D		11	%		8	%
	Customer E		6	%		10	%
	Customer F		1	%		18	%
	The concentration risk is mitigated primarily by the customers being large investment grade organizations. The credit worthiness of new customers is subject to review by management through consideration of the type of customer and the size of the contract.
	At December 31, 2014 and December 31, 2013, the following customers represented 10% or more of accounts receivable and unbilled revenue:
			31-Dec-14			31-Dec-13
	Customer 1		49	%		—	%
	Customer 2		26	%		28	%
	Customer 3		11	%		17	%
	Customer 4		—	%		26	%
	The Company reviews its accounts receivable amounts regularly and amounts are written down to their expected realizable value when outstanding amounts are determined not to be fully collectible. This generally occurs when the customer has indicated an inability to pay, the Company is unable to communicate with the customer over an extended period of time, and other methods to obtain payment have been considered and have not been successful. Bad debt expense is charged to project costs in the Consolidated Statements of Operations in the period that the account is determined to be doubtful. Estimates of the allowance for doubtful accounts are determined on a customer-by-customer evaluation of collectability at each reporting date taking into consideration the following factors: the length of time the receivable has been outstanding, specific knowledge of each customer’s financial condition and historical experience.
	The Company’s maximum exposure to credit risk for accounts receivable and unbilled revenue is as follows:
			31-Dec-14				31-Dec-13
	Trade accounts receivables		$	65,474			$	68,364
	Other receivables		1,029				1,813
	Total accounts receivable		$	66,503			$	70,177
	Unbilled revenue		$	43,622			$	32,168
	Payment terms are per the negotiated customer contracts and generally range between net 30 days and net 60 days. As at December 31, 2014 and December 31, 2013, trade receivables are aged as follows:
			31-Dec-14				31-Dec-13
	Not past due		$	60,543			$	59,337
	Past due 1-30 days		3,658				3,948
	Past due 31-60 days		2				1,538
	More than 61 days		1,271				3,541
	Total		$	65,474			$	68,364
	As at December 31, 2014, the Company has recorded an allowance for doubtful accounts of $nil (December 31, 2013 – $nil). The allowance is an estimate of the December 31, 2014 trade receivable balances that are considered uncollectible. Changes to the allowance are as follows:
Year ended December 31,		2014				2013
Opening balance		$	—			$	185
Current year allowance		164				365
Write-offs		(164		)		—
Discontinued operations		—				(550		)
Ending balance		$	—			$	—

Other_long_term_obligations

Other long term obligations	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Other long term obligations	Other long term obligations
	a) Other long term obligations are as follows:
		31-Dec-14			31-Dec-13
	Deferred lease inducements liability (note 16(b))	252			359
	Asset retirement obligation (note 16(c))	562			512
	Senior executive stock option plan (note 23(c))	22			940
	Restricted share unit plan (note 23(d))	1,779			3,667
	Directors' deferred stock unit plan (note 23(e))	2,005			3,662
	Deferred gain on sale leaseback (note 16(d))	371			—
		$	4,991		$	9,140
	Less current portion of:
	Senior executive stock option plan (note 23(c))	(22		)	—
	Restricted share unit plan (note 23(d))	(1,009		)	(1,933		)
	Directors' deferred share unit plan (note 23(f))	(408		)	—
	Deferred gain on sale leaseback (note 16(d))	(93		)	—
		$	3,459		$	7,207
	b) Deferred lease inducements liability
	Lease inducements applicable to lease contracts are deferred and amortized as a reduction of general and administrative expenses on a straight-line basis over the lease term, which includes the initial lease term and renewal periods only where renewal is determined to be reasonably assured.
		31-Dec-14			31-Dec-13
	Balance, beginning of year	$	359		$	466
	Amortization of deferred lease inducements	(107		)	(107		)
	Balance, end of year	$	252		$	359
	c) Asset retirement obligation
	The Company recorded an asset retirement obligation related to the future retirement of a facility on leased land. Accretion expense associated with this obligation is included in equipment costs in the Consolidated Statements of Operations.
	The following table presents a continuity of the liability for the asset retirement obligation:
		31-Dec-14			31-Dec-13
	Balance, beginning of year	$	512		$	466
	Accretion expense	50			46
	Balance, end of year	$	562		$	512
	At December 31, 2014, estimated undiscounted cash flows required to settle the obligation were $1,084 (December 31, 2013 – $1,084). The credit adjusted risk-free rate assumed in measuring the asset retirement obligation was 9.42%. The Company expects to settle this obligation in 2021.
	d) Deferred gain on sale leaseback
	The Company recorded a gain on the sale leaseback of certain heavy equipment. The gain on sale has been deferred and is being amortized over the term of the capital lease.
		December 31, 2014			31-Dec-13
	Balance, beginning of year	$	—		$	—
	Addition	371			—
	Balance, end of year	$	371		$	—

Shares

Shares	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Shares	Shares
	a) Common shares
	Authorized:
	Unlimited number of voting common shares
	Unlimited number of non-voting common shares
	Issued and outstanding:
		Voting common shares			Treasury shares			Common shares outstanding, net of treasury shares
	Issued and outstanding at December 31, 2012	36,251,006			—			36,251,006
	Issued upon exercise of stock options	295,230			—			295,230
	Retired through Share Purchase Program (note 17(c))	(1,800,000	)		—			(1,800,000	)
	Issued and outstanding at December 31, 2013	34,746,236			—			34,746,236
	Issued upon exercise of stock options	385,880			—			385,880
	Issued upon exercise of senior executive stock options	291,800			—			291,800
	Purchase of treasury shares for settlement of certain equity classified stock-based compensation (note 23(d(ii)), 23(e) and 23(f(ii)))	—			(589,892	)		(589,892	)
	Retired through Share Purchase Program (note 17(c))	(500,000	)		—			(500,000	)
	Issued and outstanding at December 31, 2014	34,923,916			(589,892	)		34,334,024
	On June 12, 2014, the Company entered into a trust fund agreement whereby the trustee will purchase and hold common shares, classified as treasury shares on our consolidated balance sheet, until such time that units issued under certain stock-based compensation plans are to be settled (note 23(d(ii)), 23(e) and 23(f(ii))).
	b) Net (loss) income per share
	Year ended December 31,	2014				2013
	Net loss from continuing operations	$	(697	)		$	(18,047	)
	Net (loss) income from discontinued operations	(472		)		87,231
	Net (loss) income	$	(1,169	)		$	69,184
	Weighted average number of common shares	35,014,418				36,269,996
	Basic per share information
	Net loss from continuing operations	$	(0.02	)		$	(0.50	)
	Net (loss) income from discontinued operations	(0.01		)		2.41
	Net (loss) income	$	(0.03	)		$	1.91
	Dilutive effect of stock options and treasury shares	—				342,957
	Weighted average number of diluted common shares	35,014,418				36,612,953
	Diluted per share information
	Net loss from continuing operations	$	(0.02	)		$	(0.50	)
	Net (loss) income from discontinued operations	(0.01		)		2.39
	Net income	$	(0.03	)		$	1.89
	For the year ended December 31, 2014, there were 1,765,920 stock options which were anti-dilutive (December 31, 2013 – 863,414) and therefore were not considered in computing diluted earnings per share.
	c) Share purchase program
	Effective December 18, 2014, the Company commenced a normal course issuer bid for up to 1,771,195 voting common shares, in the United States primarily through the facilities of the New York Stock Exchange ("NYSE"). Such voting common shares represented approximately 5% of the issued and outstanding voting common shares as of December 10, 2014. As of December 31, 2014, 500,000 voting common shares had been retired, resulting in a reduction of $4,238 to common shares and an increase to additional paid-in capital of $2,297.
	During the year ended December 31, 2013, the Company purchased and subsequently cancelled 1,800,000 voting common shares, in the normal course, in the United States primarily through the facilities of the NYSE. Such voting common shares represented 5% of the issued and outstanding voting common shares. This transaction resulted in a $16,133 reduction to common shares and a $4,393 increase to additional paid-in capital.
	d) Dividends
	On February 19, 2014, the Board of Directors approved the implementation of a new dividend policy (the "Dividend Policy") as part of the Company's long term strategy to maximize shareholders' value and to broaden the shareholder base. Pursuant to the Dividend Policy, the Company intends to pay an annual aggregate dividend of eight Canadian cents ($0.08) per common share, payable on a quarterly basis.
	The Company paid regular quarterly cash dividends of $0.02 per share on common shares during the year ended December 31, 2014 on each of the following dates: April 21, 2014; July 21, 2014; and October 21, 2014. At December 31, 2014, an amount of $697 was included in accrued liabilities related to the fourth quarter dividend. This amount was subsequently paid to shareholders on January 23, 2015.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2014
Commitments Disclosure [Abstract]
Commitments	Commitments
	The annual future minimum lease payments for heavy equipment, office equipment and premises in respect of operating leases, excluding contingent rentals, for the next five years and thereafter are as follows:
	For the year ending December 31,
	2015	$	5,068
	2016	4,214
	2017	3,980
	2018	4,013
	2019 and thereafter	15,357
		$	32,632
	Total contingent rentals on operating leases consisting principally of usage (recovery) charges in excess of minimum contracted amounts for the years ended December 31, 2014 and 2013 amounted to $2,116 and $(249), respectively.

Contingencies

Contingencies	12 Months Ended
	Dec. 31, 2014
Contingencies Disclosure [Abstract]
Contingencies	Contingencies
	During the normal course of the Company’s operations, various legal and tax matters are pending. In the opinion of management, these matters will not have a material effect on the Company’s consolidated financial position or results of operations.

Subsequent_events

Subsequent events	12 Months Ended
	Dec. 31, 2014
Subsequent Events [Abstract]
Subsequent events	Subsequent events
	On January 2, 2015, under the terms of a long-term customer contract the Company completed the buyout of certain contract-specific equipment leases, the sale of contract-specific assets, and the assignment of other contract-specific equipment leases to the customer and received net proceeds of $36,347. Additionally, the Company completed the reconciliation of financial amounts related to the wind-up of this long-term contract, resulting in an immaterial out-of-period expense being recorded in the current year.

Interest_expense

Interest expense	12 Months Ended
	Dec. 31, 2014
Interest Expense [Abstract]
Interest expense	Interest expense
	Year ended December 31,	2014		2013
	Interest on capital lease obligations	$	3,103	$	2,716
	Amortization of deferred financing costs (note 11(c))	1,594		4,326
	Interest on Credit Facility	1,268		2,424
	Interest on Series 1 Debentures	6,168		12,507
	Interest on long term debt	$	12,133	$	21,973
	Other interest expense (income)	102		(276		)
		$	12,235	$	21,697

Discontinued_operations

Discontinued operations	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Discontinued operations	Discontinued operations
	In prior years, the Company disposed of two businesses, comprising the commercial and industrial construction segment, and classified their results as discontinued operations. On November 22, 2012, the Company sold its pipeline related assets and exited the pipeline business. On July 12, 2013, the Company sold its piling related assets and liabilities, excluding accounts receivable and unbilled revenue on a certain customer contract, and exited the piling, foundation, pipeline anchor and tank services businesses. The terms of the piling sale agreement entitle the Company to additional proceeds of up to $92,500 over the three years following the sale, contingent on the purchaser achieving certain "net income before interest expense, income taxes, depreciation and amortization" ("EBITDA") thresholds from the assets and liabilities sold.
	During the year ended December 31, 2014 the Company recorded costs of $472 to discontinued operations related to closing costs on a certain customer contract not sold to the purchaser and costs related to the review of the first year contingent proceeds. The detailed discontinued operations results for the prior year are as follows:
	Year ended December 31,	2013
		Pipeline			Piling			Total
	Revenue	$	—		$	98,735		$	98,735
	Project costs	1,321			79,472			80,793
	Equipment costs	—			1,242			1,242
	Depreciation	—			706			706
	Gross (loss) profit	$	(1,321	)	$	17,315		$	15,994
	General and administrative expenses	312			6,857			7,169
	Loss (gain) on disposal of assets and liabilities	63			(98,065		)	(98,002		)
	Gain on sale of inventory	(46		)	—			(46		)
	Amortization of intangible assets	—			351			351
	Operating (loss) income	$	(1,650	)	$	108,172		$	106,522
	Interest expense	—			4,758			4,758
	(Loss) income before income taxes	$	(1,650	)	$	103,414		$	101,764
	Current income tax expense	—			164			164
	Deferred income tax (benefit) expense	(510		)	14,879			14,369
	Net (loss) income	$	(1,140	)	$	88,371		$	87,231
	Cash (used in) provided by discontinued operations during the prior year are summarized as follows:
	Year ended December 31,	2013
		Pipeline			Piling			Total
	Operating activities	$	(1,587	)	$	47,326		$	45,739
	Investing activities	—			182,836			182,836
	Financing activities	—			(271		)	(271		)
		$	(1,587	)	$	229,891		$	228,304

Stockbased_compensation

Stock-based compensation	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation	Stock-based compensation
	a) Stock-based compensation expenses
	Stock-based compensation expenses included in general and administrative expenses are as follows:
	Year ended December 31,		2014				2013
	Share option plan (note 23(b))		$	921			$	981
	Liability classified restricted share unit plan (note 23(d(i)))		790				2,652
	Equity classified restricted share unit plan (note 23(d(ii)))		419				—
	Performance restricted share unit plan (note 23(e))		94				—
	Liability classified deferred stock unit plan (note 23(f(i)))		(1,100		)		2,560
	Equity classified deferred stock unit plan (note 23(f(ii)))		2,181				—
			$	3,305			$	6,193
	b) Share option plan
	Under the 2004 Amended and Restated Share Option Plan, which was approved and became effective in 2006, directors, officers, employees and certain service providers to the Company are eligible to receive stock options to acquire voting common shares in the Company. Each stock option provides the right to acquire one common share in the Company and expires ten years from the grant date or on termination of employment. Options may be exercised at a price determined at the time the option is awarded, and vest as follows: no options vest on the award date and twenty percent vest on each subsequent anniversary date.
			Number of options			Weighted average
						exercise price
						$ per share
	Outstanding at December 31, 2012		3,029,734			5.7
	Granted		177,400			5.91
	Exercised(i)		(295,230	)		3.98
	Forfeited		(698,624	)		7.12
	Outstanding at December 31, 2013		2,213,280			5.51
	Exercised(i)		(385,880	)		3.49
	Forfeited		(61,480	)		7.83
	Outstanding at December 31, 2014		1,765,920			5.87
	(i)	All stock options exercised resulted in new common shares being issued (note 17(a));
	Cash received from option exercises for the year ended December 31, 2014 was $1,348 (2013 - $1,175). For the year ended December 31, 2014, the total intrinsic value of options exercised, calculated as market value at the exercise date less exercise price, multiplied by the number of units exercised, was $1,711 (December 31, 2013 - $524).
	The following table summarizes information about stock options outstanding at December 31, 2014:
			Options outstanding							Options exercisable
	Exercise price		Number			Weighted		Weighted		Number	Weighted	Weighted
						average		average exercise			average	average exercise
						remaining life		price			remaining life	price
	$2.75		373,760			7.5 years		$	2.75	109,760	7.5 years	$	2.75
	$2.79		450,000			7.5 years		$	2.79	—	—	$	—
	$3.69		38,900			3.9 years		$	3.69	38,900	3.9 years	$	3.69
	$4.90		40,000			7.3 years		$	4.9	16,000	7.3 years	$	4.9
	$5.00		142,760			1.3 years		$	5	142,760	1.3 years	$	5
	$5.91		166,600			9.0 years		$	5.91	33,320	9.0 years	$	5.91
	$6.56		94,560			6.9 years		$	6.56	55,120	6.9 years	$	6.56
	$8.28		60,000			4.5 years		$	8.28	60,000	4.5 years	$	8.28
	$8.58		30,000			5.7 years		$	8.58	24,000	5.7 years	$	8.58
	$9.33		71,580			5.1 years		$	9.33	59,840	5.1 years	$	9.33
	$10.13		68,860			6.0 years		$	10.13	56,120	6.0 years	$	10.13
	$13.21		75,000			3.0 years		$	13.21	75,000	3.0 years	$	13.21
	$13.50		76,140			2.9 years		$	13.5	76,140	2.9 years	$	13.5
	$16.46		50,000			3.3 years		$	16.46	50,000	3.3 years	$	16.46
	$16.75		27,760			1.7 years		$	16.75	27,760	1.7 years	$	16.75
			1,765,920			6.1 years		$	5.87	824,720	4.5 years	$	8.41
	At December 31, 2014, the weighted average remaining contractual life of outstanding options is 6.1 years (December 31, 2013 – 6.9 years). The fair value of options vested during the year ended December 31, 2014 was $983 (December 31, 2013 – $1,278). At December 31, 2014, the Company had 824,720 exercisable options (December 31, 2013 – 892,700) with a weighted average exercise price of $8.41 (December 31, 2013 – $8.00).
	At December 31, 2014, the total compensation costs related to non-vested awards not yet recognized was $1,223 (December 31, 2013 – $1,762) and these costs are expected to be recognized over a weighted average period of 2.5 years (December 31, 2013 – 3.2 years).
	c) Senior executive stock option plan
	On September 22, 2010, the Company modified a senior executive employment agreement to allow the option holder the right to settle options in cash which resulted in a change in classification of 550,000 stock options (senior executive stock options) from equity to a long term liability. The liability is measured at fair value using the Black-Scholes model at the modification date and subsequently at each period end date.
	At December 31, 2014, a current liability of $22 (2013- $nil) is included in accrued liabilities in relation to this plan and the long term portion of $nil (2013 - $940) is included in other long term obligations. During the year ended December 31, 2014, 291,800 of the senior executive stock options were exercised and settled in common shares (December 31, 2013 - nil). For the year ended December 31, 2014, the total intrinsic value of senior executive stock options exercised, calculated as market value at the exercise date less exercise price, multiplied by the number of units exercised, was $935 (December 31, 2013 - $nil). Cash received from stock option exercises for the year ended December 31, 2014 was $1,459 (December 31, 2013 - $nil).
	The weighted average assumptions used in estimating the fair value of the fully vested senior executive stock options as at December 31, 2014 and 2013 are as follows:
	Year ended December 31,		2014			2013
	Number of senior executive stock options		258,200			550,000
	Weighted average fair value per option granted ($)		0.08			1.71
	Weighted average assumptions:
	Dividend yield		2.2	%		N/A
	Expected volatility		49.68	%		39.12	%
	Risk-free interest rate		0.25	%		0.22	%
	Expected life (years)		0.4			1.4
	d) Restricted share unit plan
	Restricted Share Units (“RSU”) are granted each year to executives and other key employees with respect to services to be provided in that year and the following two years. The majority of RSUs vest at the end of a three-year term. The Company intends to settle all RSUs issued after February 19, 2014 with common shares purchased on the open market through a trust arrangement ("equity classified RSUs"). The Company will continue to settle RSUs granted prior to February 19, 2014 with cash ("liability classified RSUs").
	i) Liability classified restricted share unit plan
		Number of units
Outstanding at December 31, 2012		1,110,275
Granted		555,204
Vested		(154,330	)
Forfeited		(487,205	)
Outstanding at December 31, 2013		1,023,944
Dividend equivalents granted		695
Vested		(350,271	)
Forfeited		(58,865	)
Outstanding at December 31, 2014		615,503
At December 31, 2014, the current portion of RSU liabilities of $1,009 were included in accrued liabilities (December 31, 2013 - $1,933) and the long term portion of RSU liabilities of $770 were included in other long term obligations (December 31, 2013 — $1,734) in the Consolidated Balance Sheets. During the year ended December 31, 2014, 350,271 units were settled in cash for $2,678 (2013 - 154,330 units settled in cash for $727).
Using a fair market value of $3.78 per unit at December 31, 2014 (December 31, 2013 - $6.24), there were approximately $641 of total unrecognized compensation costs related to non–vested share–based payment arrangements under the liability classified RSU Plan (December 31, 2013 – $2,958) and these costs are expected to be recognized over the weighted average remaining contractual life of the liability classified RSUs of 0.8 years (December 31, 2013 – 1.3 years).
ii) Equity classified restricted share unit plan
		Number of units			Weighted average exercise price
					$ per share
Outstanding at December 31, 2013		—			—
Granted		274,256			7.98
Dividend equivalents granted		11,557			6.15
Vested		(605	)		7.75
Forfeited		(22,300	)		7.87
Outstanding at December 31, 2014		262,908			7.91
At December 31, 2014, there were approximately $1,276 of total unrecognized compensation costs related to non–vested share–based payment arrangements under the equity classified RSU Plan (December 31, 2013 – $nil) and these costs are expected to be recognized over the weighted average remaining contractual life of the RSUs of 2.3 years (December 31, 2013 – nil years). At December 31, 2014, there were 605 units vested, which were settled on February 3, 2015 with common shares purchased on the open market through a trust arrangement (December 31, 2013 - $nil units).
e) Performance restricted share units
On June 11, 2014, the Company entered into an amended and restated executive employment agreement with the Chief Executive Officer (the "CEO") and granted Performance Restricted Share Units ("PSU") as a long-term incentive, which became effective July 1, 2014. The PSUs vest at the end of a three-year term and are subject to performance criteria approved by the Human Resources and Compensation Committee at the date of the grant. The fair market value of the award granted on July 1, 2014 is $563, which will be recognized over the three-year term.
At December 31, 2014, there were approximately $468 of total unrecognized compensation costs related to non–vested share–based payment arrangements under the performance restricted share unit plan and these costs are expected to be recognized over the weighted average remaining contractual life of the PSUs of 2.5 years. The Company intends to settle earned PSUs with common shares purchased on the open market through a trust arrangement.
f) Deferred stock unit plan
On November 27, 2007, the Company approved a Directors’ Deferred Stock Unit (“DDSU”) Plan, which became effective January 1, 2008. On February 19, 2014, the Company modified its DDSU plan to permit awards to executives in addition to directors. As a result of this change, the plan will be referred to as the deferred stock unit ("DSU") plan going forward. Under the DSU plan non-officer directors of the Company receive 50% of their annual fixed remuneration (which is included in general and administrative expenses) in the form of DSUs and may elect to receive all or a part of their annual fixed remuneration in excess of 50% in the form of DSUs. Similarly, executives receive 50% of their annual bonus in the form of DSUs and may elect to receive all or part of their annual bonus in excess of 50% in the form of DSUs. The DSUs vest immediately upon issuance and are only redeemable upon death or retirement of the participant. Directors, who are not US taxpayers, may elect to defer the redemption date until a date no later than December 1st of the calendar year following the year in which the retirement or death occurred.
The Company intends to settle all DSUs issued after February 19, 2014 with common shares purchased on the open market through a trust arrangement ("equity classified DSUs"). The Company will continue to settle DSUs granted prior to February 19, 2014 with cash ("liability classified DSUs").
i) Liability classified deferred stock unit plan
		Number of units
Outstanding at December 31, 2012		625,156
Issued		141,509
Redeemed		(179,831	)
Outstanding at December 31, 2013		586,834
Issued		7,674
Redeemed		(63,886	)
Outstanding at December 31, 2014		530,622
At December 31, 2014, the fair market value of these units was $3.78 per unit (December 31, 2013 – $6.24 per unit). At December 31, 2014, the current portion of DSU liabilities of $408 were included in accrued liabilities (December 31, 2013 - $nil) and the long term portion of DSU liabilities of $1,597 were included in other long term obligations (December 31, 2013 - $3,662) in the Consolidated Balance Sheets. During the year ended December 31, 2014, 63,886 units were redeemed and settled in cash for $557 (December 31, 2013 - 179,831 units were redeemed and settled in cash for $968). There is no unrecognized compensation expense related to the DSUs, since these awards vest immediately when issued.
ii) Equity classified deferred stock unit plan
		Number of units			Weighted average exercise price
					$ per share
Outstanding at December 31, 2013		—			—
Issued		161,007			6.52
Dividend equivalents granted		8,721			6.1
Outstanding at December 31, 2014		169,728			6.5
There is no unrecognized compensation expense related to equity classified DSUs, since these awards vest immediately when issued.

Other_information

Other information	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Other information	Other information
	a) Supplemental cash flow information
	Year ended December 31,	2014			2013
	Cash paid during the year for:
	Interest	$	10,939		$	25,528
	Income taxes	—			91
	Cash received during the year for:
	Interest	63			256
	Income taxes	88			3,797
	Year ended December 31,	2014			2013
	Non-cash transactions:
	Addition of plant and equipment by means of capital leases	$	39,492		$	13,812
	Reclass from plant and equipment to assets held for sale	(1,321		)	(5,123		)
	Net increase in accounts payable related to purchase of plant and equipment	283			2,888
	Net increase in accounts payable related to purchase of intangibles	—			43
	Net decrease in accounts payable related to change in estimated financing fees	(101		)	—
	Net increase in accounts payable related to change in the lease inducement payable on the sublease	107			—
	Net decrease in short term portion of equipment lease liabilities included in accrued liabilities related to the purchase of plant and equipment	—			(159		)
	Net increase in long term portion of equipment lease liabilities related to the purchase of plant and equipment	—			1,702
	Net (decrease) increase in accrued liabilities related to current portion of RSU liability	(924		)	1,430
	Net increase (decrease) in accrued liabilities related to current portion of DSU liability	408			(253		)
	Net increase in accrued liabilities related to the current portion of the senior executive stock options	22			—
	Net increase in accrued liabilities related to dividend payable	697			—
	b) Net change in non-cash working capital
	Year ended December 31,	2014			2013
	Operating activities:
	Accounts receivable, net	$	3,674		$	29,765
	Unbilled revenue	(11,454		)	30,275
	Inventories	(1,542		)	(644		)
	Prepaid expenses and deposits	(780		)	634
	Accounts payable	9,928			(31,847		)
	Accrued liabilities	(954		)	(1,603		)
	Long term portion of liabilities related to equipment leases	—			(209		)
	Billings in excess of costs incurred and estimated earnings on uncompleted contracts	(6,357		)	(872		)
		$	(7,485	)	$	25,499

Claims_revenue

Claims revenue	12 Months Ended
	Dec. 31, 2014
Contractors [Abstract]
Claims revenue	Claims revenue
	Year ended December 31,	2014		2013
	Claims revenue recognized	$	8,230	$	17,053
	Claims revenue uncollected (classified as unbilled revenue)	4,622		8,074

Employee_benefit_plans

Employee benefit plans	12 Months Ended
	Dec. 31, 2014
Compensation and Retirement Disclosure [Abstract]
Employee benefit plans	Employee benefit plans
	The Company and its subsidiaries match voluntary contributions made by employees to their Registered Retirement Savings Plans to a maximum of 5% of base salary for each employee. Contributions made by the Company during the year ended December 31, 2014 were $1,215 (2013 – $1,565).

Comparative_figures

Comparative figures	12 Months Ended
	Dec. 31, 2014
Comparative figures [Abstract]
Comparative figures	Comparative figures
	Certain comparative figures have been reclassified from statements previously presented to conform to the presentation of the current year consolidated financial statements.

Significant_accounting_policie1

Significant accounting policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of presentation	Basis of presentation
	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 Engineering Inc.		• North American Site Development Ltd.
	• North American Enterprises Ltd.		• North American Maintenance Ltd.
	• North American Mining Inc.		• North American Tailings and Environmental Ltd.
	• North American Services Inc.		• 1753514 Alberta Ltd.
Use of estimates	Use of estimates
	The preparation of financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosures reported in these consolidated financial statements and accompanying notes and the reported amounts of revenues and expenses during the reporting period.
	Significant estimates made by management include the assessment of the percentage of completion on time-and-materials, unit-price, lump-sum and cost-plus contracts with defined scope (including estimated total costs and provisions for estimated losses) and the recognition of claims and change orders on revenue contracts; assumptions used in periodic impairment testing; and, estimates and assumptions used in the determination of the allowance for doubtful accounts, the recoverability of deferred tax assets and the useful lives of property, plant and equipment and intangible assets. Actual results could differ materially from those estimates.
	The accuracy of the Company’s revenue and profit recognition in a given period is dependent on the accuracy of its estimates of the cost to complete for each project. Cost estimates for all significant projects use a detailed “bottom up” approach and the Company believes its experience allows it to provide reasonably dependable estimates. There are a number of factors that can contribute to changes in estimates of contract cost and profitability that are recognized to the extent contract remedies are unavailable in the period in which such adjustments are determined. The most significant of these include:
	•	the completeness and accuracy of the original bid;
	•	costs associated with added scope changes;
	•	extended overhead due to owner, weather and other delays;
	•	subcontractor performance issues;
	•	changes in economic indices used for the determination of escalation or de-escalation for contractual rates on long-term contracts;
	•	changes in productivity expectations;
	•	site conditions that differ from those assumed in the original bid;
	•	contract incentive and penalty provisions;
	•	the availability and skill level of workers in the geographic location of the project; and
	•	a change in the availability and proximity of equipment and materials.
	The foregoing factors as well as the mix of contracts at different margins may cause fluctuations in gross profit between periods. With many projects of varying levels of complexity and size in process at any given time, changes in estimates can offset each other without materially impacting the Company’s profitability. Major changes in cost estimates, particularly in larger, more complex projects, can have a significant effect on profitability.
Revenue recognition	Revenue recognition
	The Company performs its projects under the following types of contracts: time-and-materials; cost-plus; unit-price; and lump-sum. Revenue is recognized as costs are incurred for time-and-materials, unit-price and cost-plus service contracts with no clearly defined scope. Revenue on cost-plus, unit-price, lump-sum and time-and-materials contracts with defined scope is recognized using the percentage-of-completion method, measured by the ratio of costs incurred to date to estimated total costs. The estimated total cost of the contract and percent complete is determined based upon estimates made by management. The costs of items that do not relate to performance of contracted work, particularly in the early stages of the contract, are excluded from costs incurred to date. The resulting percent complete methodology is applied to the approved contract value to determine the revenue recognized. Customer payment milestones typically occur on a periodic basis over the period of contract completion.
	The length of the Company’s contracts varies from less than one year for typical contracts to several years for certain larger contracts. Contract project costs include all direct labour, material, subcontract and equipment costs and those indirect costs related to contract performance such as indirect labour and supplies. General and administrative expenses are charged to expense as incurred. Provisions for estimated losses on uncompleted contracts are made in the period in which such losses are determined. Changes in project performance, project conditions, and estimated profitability, including those arising from contract penalty provisions and final contract settlements, may result in revisions to costs and revenue that are recognized in the period in which such adjustments are determined. Profit incentives are included in revenue when their realization is reasonably assured.
	Once a project is underway, the Company will often experience changes in conditions, client requirements, specifications, designs, materials and work schedule. Generally, a “change order” will be negotiated with the customer to modify the original contract to approve both the scope and price of the change. Occasionally, however, disagreements arise regarding changes, their nature, measurement, timing and other characteristics that impact costs and revenue under the contract. When a change becomes a point of dispute between the Company and a customer, the Company will then consider it as a claim.
	Costs related to unapproved change orders and claims are recognized when they are incurred.
	Revenues related to unapproved change orders and claims are included in total estimated contract revenue only to the extent that contract costs related to the claim have been incurred and when it is probable that the unapproved change order or claim will result in:
	•	a bona fide addition to contract value; and
	•	revenues can be reliably estimated.
	These two conditions are satisfied when:
	•	the contract or other evidence provides a legal basis for the unapproved change order or claim, or a legal opinion is obtained providing a reasonable basis to support the unapproved change order or claim;
	•	additional costs incurred were caused by unforeseen circumstances and are not the result of deficiencies in the Company’s performance;
	•	costs associated with the unapproved change order or claim are identifiable and reasonable in view of work performed; and
	•	evidence supporting the unapproved change order or claim is objective and verifiable.
	This can lead to a situation where costs are recognized in one period and revenue is recognized when customer agreement is obtained or claim resolution occurs, which can be in subsequent periods. Historical claim recoveries should not be considered indicative of future claim recoveries.
	The Company’s long term contracts typically allow its customers to unilaterally reduce or eliminate the scope of the work as contracted without cause. These long term contracts represent higher risk due to uncertainty of total contract value and estimated costs to complete; therefore, potentially impacting revenue recognition in future periods.
	A contract is regarded as substantially completed when remaining costs and potential risks are insignificant in amount.
	The Company recognizes revenue from equipment rental as performance requirements are achieved in accordance with the terms of the relevant agreement with the customer, either at a monthly fixed rate or on a usage basis dependent on the number of hours that the equipment is used. Revenue is recognized from the foregoing activity once persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, fees are fixed and determinable and collectability is reasonably assured.
Balance sheet classification	Balance sheet classifications
	A one-year time period is typically used as the basis for classifying current assets and liabilities. However, included in current assets and liabilities are amounts receivable and payable under construction contracts (principally holdbacks) that may extend beyond one year.
Cash	Cash
	Cash includes cash on hand and bank balances net of outstanding cheques.
Accounts receivable and unbilled revenue	Accounts receivable and unbilled revenue
	Accounts receivable are primarily comprised of amounts billed to clients for services already provided, but which have not yet been collected. Unbilled revenue represents revenue recognized in advance of amounts billed to clients.
Billings in excess of costs incurred and estimated earnings on uncompleted contracts	Billings in excess of costs incurred and estimated earnings on uncompleted contracts
	Billings in excess of costs incurred and estimated earnings on uncompleted contracts represent amounts invoiced in excess of revenue recognized.
Allowance for doubtful accounts	Allowance for doubtful accounts
	The Company evaluates the probability of collection of accounts receivable and records an allowance for doubtful accounts, which reduces accounts receivable to the amount management reasonably believes will be collected. In determining the amount of the allowance, the following factors are considered: the length of time the receivable has been outstanding, specific knowledge of each customer’s financial condition and historical experience.
Inventories	Inventories
	Inventories are carried at the lower of weighted average cost and market, and consist primarily of spare tires and tracks.
Property, plant and equipment and Capitalized interest	Property, plant and equipment
	Property, plant and equipment are recorded at cost. Major components of heavy construction equipment in use such as engines and drive trains are recorded separately. Equipment under capital lease is recorded at the present value of minimum lease payments at the inception of the lease. Depreciation is not recorded until an asset is available for use. 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
	The costs for periodic repairs and maintenance are expensed to the extent the expenditures serve only to restore the assets to their normal operating condition without enhancing their service potential or extending their useful lives.
	k) Capitalized interest
	The Company capitalizes interest incurred on debt during the construction of assets for the Company’s own use. The capitalization period covers the duration of the activities required to get the asset ready for its intended use, provided that expenditures for the asset have been made and interest cost incurred. Interest capitalization continues as long as those activities and the incurrence of interest cost continue. The capitalized interest is amortized at the same rate as the respective asset.
Intangible assets	Intangible assets
	Intangible assets include capitalized computer software and development costs, which are being amortized on a straight-line basis over a maximum period of four years.
	The Company expenses or capitalizes costs associated with the development of internal-use software as follows:
	•	Preliminary project stage: Both internal and external costs incurred during this stage are expensed as incurred.
	•	Application development stage: Both internal and external costs incurred to purchase and develop computer software are capitalized after the preliminary project stage is completed and management authorizes the computer software project. However, training costs and the costs incurred for the process of data conversion from the old system to the new system, which includes purging or cleansing of existing data, reconciliation or balancing of old data to the converted data in the new system, are expensed as incurred.
	•	Post implementation/operation stage: All training costs and maintenance costs incurred during this stage are expensed as incurred.
	Costs of upgrades and enhancements are capitalized if the expenditures will result in adding functionality to the software.
Impairment of long-lived assets	Impairment of long-lived assets
	Long-lived assets or asset groups held and used including plant, equipment and identifiable intangible assets subject to amortization are reviewed for impairment whenever events or changes in circumstances indicate that the carrying amount of an asset may not be recoverable. If the sum of the undiscounted future cash flows expected to result from the use and eventual disposition of an asset or group of assets is less than its carrying amount, it is considered to be impaired. The Company measures the impairment loss as the amount by which the carrying amount of the asset or group of assets exceeds its fair value, which is charged to depreciation or amortization expense. In determining whether an impairment exists, the Company makes assumptions about the future cash flows expected from the use of its long-lived assets, such as: applicable industry performance and prospects; general business and economic conditions that prevail and are expected to prevail; expected growth; maintaining its customer base; and, achieving cost reductions. There can be no assurance that expected future cash flows will be realized, or will be sufficient to recover the carrying amount of long-lived assets. Furthermore, the process of determining fair values is subjective and requires management to exercise judgment in making assumptions about future results, including revenue and cash flow projections and discount rates.
Assets held for sale	Assets held for sale
	Long-lived assets are classified as held for sale when certain criteria are met, which include:
	•	management, having the authority to approve the action, commits to a plan to sell the assets;
	•	the assets are available for immediate sale in their present condition;
	•	an active program to locate buyers and other actions to sell the assets have been initiated;
	•	the sale of the assets is probable and their transfer is expected to qualify for recognition as a completed sale within one year;
	•	the assets are being actively marketed at reasonable prices in relation to their fair value; and
	•	it is unlikely that significant changes will be made to the plan to sell the assets or that the plan will be withdrawn.
	Assets to be disposed of by sale are reported at the lower of their carrying amount or estimated fair value less costs to sell and are disclosed separately on the Consolidated Balance Sheets. These assets are not depreciated.
Asset retirement obligations	Asset retirement obligations
	Asset retirement obligations are legal obligations associated with the retirement of property, plant and equipment that result from their acquisition, lease, construction, development or normal operations. The Company recognizes its contractual obligations for the retirement of certain tangible long-lived assets. The fair value of a liability for an asset retirement obligation is recognized in the period in which it is incurred if a reasonable estimate of fair value can be made. The fair value of a liability for an asset retirement obligation is the amount at which that liability could be settled in a current transaction between willing parties, that is, other than in a forced or liquidation transaction and, in the absence of observable market transactions, is determined as the present value of expected cash flows. The associated asset retirement costs are capitalized as part of the carrying amount of the long-lived asset and then amortized using a systematic and rational method over its estimated useful life. In subsequent reporting periods, the liability is adjusted for the passage of time through an accretion charge and any changes in the amount or timing of the underlying future cash flows are recognized as an additional asset retirement cost.
Foreign currency translation	Foreign currency translation
	The functional currency of the Company its subsidiaries is Canadian Dollars. Transactions denominated in foreign currencies are recorded at the rate of exchange on the transaction date. Monetary assets and liabilities, denominated in foreign currencies, are translated into Canadian Dollars at the rate of exchange prevailing at the balance sheet date. Foreign exchange gains and losses are included in the determination of earnings.
Fair value measurement	Fair value measurement
	Fair value measurements are categorized using a valuation hierarchy for disclosure of the inputs used to measure fair value, which prioritizes the inputs into three broad levels. Fair values included in Level 1 are determined by reference to quoted prices in active markets for identical assets and liabilities. Fair values included in Level 2 include valuations using inputs based on observable market data, either directly or indirectly other than the quoted prices. Level 3 valuations are based on inputs that are not based on observable market data. The classification of a fair value within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.
Derivative financial instruments	Derivative financial instruments
	The Company used derivative financial instruments to manage financial risks from fluctuations in exchange rates. These instruments included embedded price escalation features in supplier contracts. Such instruments were only used for risk management purposes. The Company does not hold or issue derivative financial instruments for trading or speculative purposes. Derivative financial instruments are subject to standard terms and conditions, financial controls, management and risk monitoring procedures. These derivative financial instruments were not designated as hedges for accounting purposes and were recorded at fair value with realized and unrealized gains and losses recognized in the Consolidated Statements of Operations.
Income taxes	Income taxes
	The Company uses the asset and liability method of accounting for income taxes. Under the asset and liability method, deferred tax assets and liabilities are recognized based on the differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities from a change in tax rates is recognized in income in the period of enactment. The Company recognizes the effect of income tax positions only if those positions are more likely than not (greater than 50%) of being sustained. Changes in recognition or measurement are reflected in the period in which the change in judgement occurs. The Company accrues interest and penalties for uncertain tax positions in the period in which these uncertainties are identified. Interest and penalties are included in “General and administrative expenses” in the Consolidated Statements of Operations. A valuation allowance is recorded against any deferred tax asset if it is more likely than not that the asset will not be realized.
Stock-based compensation	Stock-based compensation
	The Company has a Share Option Plan which is described in note 23(b). The Company accounts for all stock-based compensation payments that are settled by the issuance of equity instruments at fair value. Compensation cost is measured using the Black-Scholes model at the grant date and is expensed on a straight-line basis over the award’s vesting period, with a corresponding increase to additional paid-in capital. Upon exercise of a stock option, share capital is recorded at the sum of proceeds received and the related amount of additional paid-in capital.
	The Company has a Senior Executive Stock Option Plan which is described in note 23(c). This compensation plan allows the option holder the right to settle options in cash. The liability is measured at fair value using the Black-Scholes model at the modification date and subsequently at each period end date. Changes in fair value of the liability are recognized in the Consolidated Statements of Operations when the period end fair value exceeds the fair value at the modification date and in the Consolidated Balance Sheets when the period end fair value is less than the fair value at the modification date.
	The Company has a Restricted Share Unit (“RSU”) Plan which is described in note 23(d). RSUs are granted effective April 1 of each fiscal year with respect to services to be provided in that fiscal year and the following two fiscal years. The RSUs generally vest at the end of the three-year term. When dividends are paid on common shares, additional dividend equivalent RSUs are granted to all RSU holders as of the dividend payment date. The number of additional RSUs to be granted is determined by multiplying the dividend payment per common share by the number of outstanding RSUs, divided by the fair market value of the Company's common shares on the dividend payment date. Such additional RSUs are granted subject to the same service criteria as the underlying RSUs. The Company settles all RSUs issued after February 19, 2014, with common shares purchased on the open market through a trust arrangement ("equity classified RSUs"). The Company will continue to settle the existing RSUs with cash ("liability classified RSUs"). Compensation expense is calculated based on the number of vested RSUs multiplied by the fair market value of each RSU as determined by the volume weighted average trading price of the Company’s common shares for the five trading days immediately preceding the day on which the fair market value is to be determined. The Company recognizes compensation cost over the three-year term of the RSU in the Consolidated Statements of Operations, with a corresponding increase to liability for the liability classified RSUs and additional paid-in capital for the equity classified RSUs. When dividends are paid on common shares, additional dividend equivalent RSUs are granted to all RSU holders as of the dividend payment date. The number of additional RSUs to be granted is determined by multiplying the dividend payment per common share by the number of outstanding RSUs, divided by the fair market value of the Company's common shares on the dividend payment date. Such additional RSUs are granted subject to the same service criteria as the underlying RSUs.
	The Company has a Performance restricted share unit ("PSU") plan which is described in note 23(e). The PSUs vest at the end of a three-year term and are subject to the performance criteria approved by the Human Resources and Compensation Committee at the date of the grant. Such performance criterion includes the passage of time and is based upon the improvement of total shareholder return ("TSR") as compared to a defined company Canadian peer group. TSR is calculated using the fair market values of voting common shares at the grant date, the fair market value of voting common shares at the vesting date and the total dividends declared and paid throughout the vesting period. At the maturity date, the Human Resources and Compensation Committee will assess actual performance against the performance criteria and determine the number of PSUs that have been earned. The company intends to settle all PSUs with common shares purchased on the open market through a trust arrangement. The Company recognizes compensation cost over the three-year term of the PSU in the Consolidated Statement of Operations, with a corresponding increase to liability.
	The Company has a Deferred Stock Unit (“DSU”) Plan which is described in note 23(f). Prior to the year ended December 31, 2014, this plan was referred to as the Directors Deferred Share Unit ("DDSU") Plan as only directors were awarded under it. During the year ended December 31, 2014, the plan was modified to include executives and has since been referred to as the DSU plan. The DSU plan enables directors and executives to receive all or a portion of their annual fee or annual executive bonus compensation in the form of DSUs. The DSUs issued prior to February 19, 2014, are settled in cash ("liability classified DSUs") and all DSUs and dividend equivalents issued after this date are settled in common shares ("equity classified DSUs") purchased on the open market through a defined trust arrangement. Compensation expense is calculated based on the number of DSUs multiplied by the fair market value of each DSU as determined by the volume weighted average trading price of the Company’s common shares for the five trading days immediately preceding the day on which the fair market value is to be determined, with a corresponding increase to liability for the liability classified DSUs and additional paid-in capital for the equity classified DSUs. Compensation costs related to DSUs are recognized in full upon the grant date as the units vest immediately. When dividends are paid on common shares, additional dividend equivalent DSUs are granted to all DSU holders as of the dividend payment date. The number of additional DSUs to be granted is determined by multiplying the dividend payment per common share by the number of outstanding DSUs, divided by the fair market value of the Company's common shares on the dividend payment date. Such additional DSUs are granted subject to the same service criteria as the underlying DSUs.
Net income (loss) per share	Net income (loss) per share
	Basic net income (loss) per share is computed by dividing net income (loss) available to common shareholders by the weighted average number of shares outstanding during the year (see note 17(b)). Diluted per share amounts are calculated using the treasury stock method. The treasury stock method increases the diluted weighted average shares outstanding to include additional shares from the assumed exercise of stock options, if dilutive. The number of additional shares is calculated by assuming outstanding in-the-money stock options were exercised and the proceeds from such exercises, including any unamortized stock-based compensation cost, were used to acquire shares of common stock at the average market price during the year.
Leases	Leases
	Leases entered into by the Company in which substantially all the benefits and risks of ownership are transferred to the Company are recorded as obligations under capital leases and under the corresponding category of property, plant and equipment. Obligations under capital leases reflect the present value of future lease payments, discounted at an appropriate interest rate, and are reduced by rental payments net of imputed interest. All other leases are classified as operating leases and leasing costs, including any rent holidays, leasehold incentives, and rent concessions, are amortized on a straight-line basis over the lease term.
	Certain operating lease and rental agreements provide a maximum hourly usage limit, above which the Company will be required to pay for the over hour usage as a contingent rent expense. These contingent expenses are recognized when the likelihood of exceeding the usage limit is considered probable and are due at the end of the lease term or rental period. The contingent rental expenses are included in “Equipment operating lease expense” in the Consolidated Statements of Operations.
Deferred financing costs	Deferred financing costs
	Underwriting, legal and other direct costs incurred in connection with the issuance of debt not measured under the fair value option are presented as deferred financing costs. The deferred financing costs related to the Debentures and the Revolving and Term Facilities are amortized over the term of the related debt using the effective interest method.
Business combinations	Business combinations
	The Company accounts for all business combinations using the acquisition method. Acquisition related costs which include finder’s fees, advisory, legal, accounting, valuation, other professional or consulting fees, and administrative costs are expensed as incurred.
Discontinued operations	Discontinued operations
	In prior years the Company divested certain of its business operations. These businesses are presented as discontinued operations in the Company's Consolidated Statement of Operations and Comprehensive (Loss) Income and, collectively, are included in the line item "(Loss) income from discontinued operations, net of tax" for all periods presented. The cash flows from discontinued operations are included in the "Cash (used in) provided by discontinued operations" section of the Consolidated Statement of Cash Flows for all periods presented. The Company allocates interest expense incurred on debt that is required to be repaid as a result of the disposal transaction to discontinued operations. The allocation to discontinued operations of other consolidated interest that is not directly attributable to or related to other operations of the Company is allocated based on a ratio of net assets to be sold to total consolidated net assets.

Significant_accounting_policie2

Significant accounting policies (Tables)	12 Months Ended
	Dec. 31, 2014
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 Engineering Inc.	• North American Site Development Ltd.
	• North American Enterprises Ltd.	• North American Maintenance Ltd.
	• North American Mining Inc.	• North American Tailings and Environmental Ltd.
	• North American Services Inc.	• 1753514 Alberta Ltd.
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, 2014	Cost			Accumulated		Net Book Value
					Deprecation
	Heavy equipment	$	142,052		$	42,292	$	99,760
	Major component parts in use	112,645			55,895		56,750
	Other equipment	41,739			18,758		22,981
	Licensed motor vehicles	24,247			20,763		3,484
	Office and computer equipment	9,355			8,216		1,139
	Buildings	2,791			2,606		185
	Assets under capital lease	101,606			25,007		76,599
		$	434,435		$	173,537	$	260,898
	December 31, 2013	Cost			Accumulated		Net Book Value
					Deprecation
	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

Accounts_receivable_Tables

Accounts receivable (Tables)	12 Months Ended
	Dec. 31, 2014
Receivables [Abstract]
Schedule of accounts receivable
		December 31, 2014		December 31, 2013
	Accounts receivable – trade	$	54,733	$	59,309
	Accounts receivable – holdbacks	10,741		9,055
	Accounts receivable – other	1,029		1,813
	Allowance for doubtful accounts (note 15(d))	—		—
		$	66,503	$	70,177

Costs_incurred_and_estimated_e1

Costs incurred and estimated earnings net of billings on uncompleted contracts (Tables)	12 Months Ended
	Dec. 31, 2014
Contractors [Abstract]
Schedule of costs in excess of billings on uncompleted contracts
		December 31, 2014			December 31, 2013
	Costs incurred and estimated earnings on uncompleted contracts	$	629,416		$	533,837
	Less billings to date	(585,794		)	(508,026		)
		$	43,622		$	25,811
	Costs incurred and estimated earnings net of billings on uncompleted contracts is presented in the Consolidated Balance Sheets under the following captions:
		December 31, 2014			December 31, 2013
	Unbilled revenue	$	43,622		$	32,168
	Billings in excess of costs incurred and estimated earnings on uncompleted contracts	—			(6,357		)
		$	43,622		$	25,811

Prepaid_expenses_and_deposits_

Prepaid expenses and deposits (Tables)	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of prepaid expenses and deposits
	Current:
		December 31, 2014		December 31, 2013
	Prepaid insurance and deposits	$	968	$	1,076
	Prepaid lease payments	537		880
	Prepaid interest	748		196
		$	2,253	$	2,152
	Long term:
		December 31, 2014		December 31, 2013
	Prepaid lease payments (note 11(a))	$	1,953	$	1,274

Income_taxes_Tables

Income taxes (Tables)	12 Months Ended
	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Schedule of differences between tax provision and Federal and Provincial statutory income taxes	Income tax provision differs from the amount that would be computed by applying the Federal and Provincial statutory income tax rates to income before income taxes. The reasons for the differences are as follows:
	Year ended December 31,	2014			2013
	Loss before income taxes	$	(728	)	$	(24,149	)
	Tax rate	25.26		%	25.26		%
	Expected benefit	$	(184	)	$	(6,101	)
	(Decrease) increase related to:
	Impact of enacted future statutory income tax rates	—			(209		)
	Income tax adjustments and reassessments	(68		)	(249		)
	Non deductible portion of capital losses	(72		)	69
	Stock-based compensation	232			315
	Other	61			73
	Income tax benefit	$	(31	)	$	(6,102	)
Schedule of classification of income tax benefit (expense)	Classified as:
	Year ended December 31,	2014			2013
	Current income tax (benefit) expense	$	(92	)	$	(2,438	)
	Deferred income tax benefit	61			(3,664		)
		$	(31	)	$	(6,102	)
Schedule of deferred tax assets and liabilities	The deferred tax assets and liabilities are summarized below:
		December 31, 2014			December 31, 2013
	Deferred tax assets:
	Non-capital losses	$	31,151		$	39,604
	Deferred financing costs	1,135			1,709
	Billings in excess of costs on uncompleted contracts	—			1,606
	Capital lease obligations	16,148			10,914
	Deferred lease inducements	64			91
	Stock-based compensation	1,666			1,880
	Other	481			409
		$	50,645		$	56,213
		December 31, 2014			December 31, 2013
	Deferred tax liabilities:
	Unbilled revenue and uncertified revenue included in accounts receivable	$	9,538		$	5,338
	Assets held for sale	6,466			13
	Accounts receivable – holdbacks	3,084			2,308
	Property, plant and equipment	58,134			56,945
	Deferred partnership income	—			18,125
		$	77,222		$	82,729
	Net deferred income tax liability	$	(26,577	)	$	(26,516	)
	Classified as:
		December 31, 2014			December 31, 2013
	Current asset	$	5,609		$	3,678
	Long term asset	29,947			27,660
	Current liability	(20,056		)	(8,036		)
	Long term liability	(42,077		)	(49,818		)
		$	(26,577	)	$	(26,516	)
Schedule of non-capital losses for income tax purposes	At December 31, 2014, the Company has non-capital losses for income tax purposes of $123,307 which predominately expire after 2026 as follows:
		31-Dec-14
	2026	$	283
	2027	—
	2028	—
	2029	1
	2030	5,334
	2031	18,567
	2032	48,910
	2033	34,788
	2034	15,424
		$	123,307

Plant_and_equipment_Tables

Plant and equipment (Tables)	12 Months Ended
	Dec. 31, 2014
Property, Plant and Equipment [Abstract]
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, 2014	Cost			Accumulated		Net Book Value
					Deprecation
	Heavy equipment	$	142,052		$	42,292	$	99,760
	Major component parts in use	112,645			55,895		56,750
	Other equipment	41,739			18,758		22,981
	Licensed motor vehicles	24,247			20,763		3,484
	Office and computer equipment	9,355			8,216		1,139
	Buildings	2,791			2,606		185
	Assets under capital lease	101,606			25,007		76,599
		$	434,435		$	173,537	$	260,898
	December 31, 2013	Cost			Accumulated		Net Book Value
					Deprecation
	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

Other_assets_Tables

Other assets (Tables)	12 Months Ended
	Dec. 31, 2014
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of other assets	Other assets are as follows:
		December 31, 2014			December 31, 2013
	Prepaid lease payments (note 7)	$	1,953		$	1,274
	Intangible assets (note 11(b))	4,385			7,043
	Deferred financing costs (note 11(c))	2,205			3,813
	Deferred lease inducement asset (note 11(d))	1,212			—
		$	9,755		$	12,130
Schedule of intangible assets	Intangible assets
		December 31, 2014			December 31, 2013
	Cost	$	17,102		$	22,713
	Accumulated amortization	12,717			15,670
	Net book value	$	4,385		$	7,043
Schedule of estimated amortization expense for future years	The estimated amortization expense for future years is as follows:
	For the year ending December 31,
	2015	$	1,815
	2016	1,410
	2017	781
	2018	379
		$	4,385
Schedule of deferred finance costs	Deferred financing costs
	31-Dec-14	Cost			Accumulated		Net Book Value
					Amortization
	Credit Facility	$	6,878		$	6,347	$	531
	Series 1 Debentures	8,644			6,970		1,674
		$	15,522		$	13,317	$	2,205
	31-Dec-13	Cost			Accumulated		Net Book Value
					Amortization
	Credit Facility	$	6,881		$	5,994	$	887
	Series 1 Debentures	8,655			5,729		2,926
		$	15,536		$	11,723	$	3,813
Schedule of deferred lease inducement assets
		31-Dec-14			31-Dec-13
	Balance, beginning of year	$	—		$	—
	Additions	1,307			—
	Amortization of deferred lease inducements	(95		)	—
	Balance, end of year	$	1,212		$	—

Accrued_liabilities_Tables

Accrued liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Payables and Accruals [Abstract]
Schedule of accrued liabilities
		31-Dec-14		31-Dec-13
	Accrued interest payable	$	1,514	$	1,836
	Payroll liabilities	9,845		11,970
	Liabilities related to equipment leases	786		190
	Current portion of deferred gain on sale leaseback (note 16(d))	93		—
	Dividends payable (note 17(d))	697		—
	Income and other taxes payable	2,062		1,659
		$	14,997	$	15,655

Long_term_debt_Tables

Long term debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Schedule of long term debt	Long term debt is as follows:
		December 31, 2014		December 31, 2013
	Credit Facility (note 13(b))	$	5,536	$	—
	Series 1 Debentures (note 13(c))	58,733		75,000
		$	64,269	$	75,000

Capital_lease_obligations_Tabl

Capital lease obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule of future minimum lease payments due under capital leases	The Company’s capital leases primarily relate to heavy equipment and licensed motor vehicles. The minimum lease payments due in each of the next five fiscal years are as follows:
	2015	$	25,115
	2016	21,149
	2017	11,662
	2018	10,179
	2019	1,778
	Subtotal:	$	69,883
	Less: amount representing interest	(5,828		)
	Present value of minimum lease payments	$	64,055
	Less: current portion	(22,201		)
	Long term portion	$	41,854

Financial_instruments_and_risk1

Financial instruments and risk management (Tables)	12 Months Ended
	Dec. 31, 2014
Concentration Risk [Line Items]
Schedule of financial instruments with carrying amounts that differ from fair values	Financial instruments with carrying amounts that differ from their fair values are as follows:
			31-Dec-14							31-Dec-13
			Carrying				Fair			Carrying		Fair
			Amount				Value			Amount		Value
	Capital lease obligations (i)		$	64,055			$	58,951		$	43,295	$	39,508
	Series 1 Debentures (ii)		58,733				58,733			75,000		77,813
	(i)	The fair values of amounts due under capital leases are based on management estimates which are determined by discounting cash flows required under the instruments at the interest rates currently estimated to be available for instruments with similar terms.
	(ii)	The fair value of the Series 1 Debentures is based upon the expected discounted cash flows and the period end market price of similar financial instruments.
Schedule of non-financial assets measured at fair value on a non-recurring basis	Non-financial assets measured at fair value on a non-recurring basis as at December 31, 2014 and December 31, 2013 in the financial statements are summarized below:
			31-Dec-14							31-Dec-13
			Carrying Amount				Change in Fair Value			Carrying Amount		Change in Fair Value
	Assets held for sale		$	29,589			$	(3,461	)	$	52	$	(3,097	)
Schedule of maximum exposure to credit risk for accounts receivable and unbilled revenue	The Company’s maximum exposure to credit risk for accounts receivable and unbilled revenue is as follows:
			31-Dec-14				31-Dec-13
	Trade accounts receivables		$	65,474			$	68,364
	Other receivables		1,029				1,813
	Total accounts receivable		$	66,503			$	70,177
	Unbilled revenue		$	43,622			$	32,168
Schedule of trade receivables aging	Payment terms are per the negotiated customer contracts and generally range between net 30 days and net 60 days. As at December 31, 2014 and December 31, 2013, trade receivables are aged as follows:
			31-Dec-14				31-Dec-13
	Not past due		$	60,543			$	59,337
	Past due 1-30 days		3,658				3,948
	Past due 31-60 days		2				1,538
	More than 61 days		1,271				3,541
	Total		$	65,474			$	68,364
Schedule of changes to the allowance for uncollectible accounts	The allowance is an estimate of the December 31, 2014 trade receivable balances that are considered uncollectible. Changes to the allowance are as follows:
	Year ended December 31,		2014				2013
	Opening balance		$	—			$	185
	Current year allowance		164				365
	Write-offs		(164		)		—
	Discontinued operations		—				(550		)
	Ending balance		$	—			$	—
Total revenues
Concentration Risk [Line Items]
Schedule of major customers	The following customers accounted for 10% or more of total revenues:
	Year ended December 31,		2014			2013
	Customer A		29	%		—	%
	Customer B		28	%		29	%
	Customer C		14	%		22	%
	Customer D		11	%		8	%
	Customer E		6	%		10	%
	Customer F		1	%		18	%
Accounts receivable and unbilled revenue
Concentration Risk [Line Items]
Schedule of major customers	At December 31, 2014 and December 31, 2013, the following customers represented 10% or more of accounts receivable and unbilled revenue:
			31-Dec-14			31-Dec-13
	Customer 1		49	%		—	%
	Customer 2		26	%		28	%
	Customer 3		11	%		17	%
	Customer 4		—	%		26	%

Other_long_term_obligations_Ta

Other long term obligations (Tables)	12 Months Ended
	Dec. 31, 2014
Other Liabilities Disclosure [Abstract]
Schedule of other long term obligations	Other long term obligations are as follows:
		31-Dec-14			31-Dec-13
	Deferred lease inducements liability (note 16(b))	252			359
	Asset retirement obligation (note 16(c))	562			512
	Senior executive stock option plan (note 23(c))	22			940
	Restricted share unit plan (note 23(d))	1,779			3,667
	Directors' deferred stock unit plan (note 23(e))	2,005			3,662
	Deferred gain on sale leaseback (note 16(d))	371			—
		$	4,991		$	9,140
	Less current portion of:
	Senior executive stock option plan (note 23(c))	(22		)	—
	Restricted share unit plan (note 23(d))	(1,009		)	(1,933		)
	Directors' deferred share unit plan (note 23(f))	(408		)	—
	Deferred gain on sale leaseback (note 16(d))	(93		)	—
		$	3,459		$	7,207
Schedule of changes in deferred lease inducements
		31-Dec-14			31-Dec-13
	Balance, beginning of year	$	359		$	466
	Amortization of deferred lease inducements	(107		)	(107		)
	Balance, end of year	$	252		$	359
Schedule of changes in asset retirement obligation	The following table presents a continuity of the liability for the asset retirement obligation:
		31-Dec-14			31-Dec-13
	Balance, beginning of year	$	512		$	466
	Accretion expense	50			46
	Balance, end of year	$	562		$	512
Schedule of deferred lease inducement assets	The Company recorded a gain on the sale leaseback of certain heavy equipment. The gain on sale has been deferred and is being amortized over the term of the capital lease.
		December 31, 2014			31-Dec-13
	Balance, beginning of year	$	—		$	—
	Addition	371			—
	Balance, end of year	$	371		$	—

Shares_Tables

Shares (Tables)	12 Months Ended
	Dec. 31, 2014
Equity [Abstract]
Schedule of common shares issued and outstanding	Issued and outstanding:
		Voting common shares			Treasury shares			Common shares outstanding, net of treasury shares
	Issued and outstanding at December 31, 2012	36,251,006			—			36,251,006
	Issued upon exercise of stock options	295,230			—			295,230
	Retired through Share Purchase Program (note 17(c))	(1,800,000	)		—			(1,800,000	)
	Issued and outstanding at December 31, 2013	34,746,236			—			34,746,236
	Issued upon exercise of stock options	385,880			—			385,880
	Issued upon exercise of senior executive stock options	291,800			—			291,800
	Purchase of treasury shares for settlement of certain equity classified stock-based compensation (note 23(d(ii)), 23(e) and 23(f(ii)))	—			(589,892	)		(589,892	)
	Retired through Share Purchase Program (note 17(c))	(500,000	)		—			(500,000	)
	Issued and outstanding at December 31, 2014	34,923,916			(589,892	)		34,334,024
Schedule of net (loss) income per share	Net (loss) income per share
	Year ended December 31,	2014				2013
	Net loss from continuing operations	$	(697	)		$	(18,047	)
	Net (loss) income from discontinued operations	(472		)		87,231
	Net (loss) income	$	(1,169	)		$	69,184
	Weighted average number of common shares	35,014,418				36,269,996
	Basic per share information
	Net loss from continuing operations	$	(0.02	)		$	(0.50	)
	Net (loss) income from discontinued operations	(0.01		)		2.41
	Net (loss) income	$	(0.03	)		$	1.91
	Dilutive effect of stock options and treasury shares	—				342,957
	Weighted average number of diluted common shares	35,014,418				36,612,953
	Diluted per share information
	Net loss from continuing operations	$	(0.02	)		$	(0.50	)
	Net (loss) income from discontinued operations	(0.01		)		2.39
	Net income	$	(0.03	)		$	1.89

Commitments_Tables

Commitments (Tables)	12 Months Ended
	Dec. 31, 2014
Commitments Disclosure [Abstract]
Schedule of future minimum lease payments for operating leases	The annual future minimum lease payments for heavy equipment, office equipment and premises in respect of operating leases, excluding contingent rentals, for the next five years and thereafter are as follows:
	For the year ending December 31,
	2015	$	5,068
	2016	4,214
	2017	3,980
	2018	4,013
	2019 and thereafter	15,357
		$	32,632

Interest_expense_Tables

Interest expense (Tables)	12 Months Ended
	Dec. 31, 2014
Interest Expense [Abstract]
Schedule of interest expense
	Year ended December 31,	2014		2013
	Interest on capital lease obligations	$	3,103	$	2,716
	Amortization of deferred financing costs (note 11(c))	1,594		4,326
	Interest on Credit Facility	1,268		2,424
	Interest on Series 1 Debentures	6,168		12,507
	Interest on long term debt	$	12,133	$	21,973
	Other interest expense (income)	102		(276		)
		$	12,235	$	21,697

Discontinued_operations_Tables

Discontinued operations (Tables)	12 Months Ended
	Dec. 31, 2014
Discontinued Operations and Disposal Groups [Abstract]
Schedule of disposed assets, results of discontinued operations and cashflow impact of discontinued operations	The detailed discontinued operations results for the prior year are as follows:
	Year ended December 31,	2013
		Pipeline			Piling			Total
	Revenue	$	—		$	98,735		$	98,735
	Project costs	1,321			79,472			80,793
	Equipment costs	—			1,242			1,242
	Depreciation	—			706			706
	Gross (loss) profit	$	(1,321	)	$	17,315		$	15,994
	General and administrative expenses	312			6,857			7,169
	Loss (gain) on disposal of assets and liabilities	63			(98,065		)	(98,002		)
	Gain on sale of inventory	(46		)	—			(46		)
	Amortization of intangible assets	—			351			351
	Operating (loss) income	$	(1,650	)	$	108,172		$	106,522
	Interest expense	—			4,758			4,758
	(Loss) income before income taxes	$	(1,650	)	$	103,414		$	101,764
	Current income tax expense	—			164			164
	Deferred income tax (benefit) expense	(510		)	14,879			14,369
	Net (loss) income	$	(1,140	)	$	88,371		$	87,231
	Cash (used in) provided by discontinued operations during the prior year are summarized as follows:
	Year ended December 31,	2013
		Pipeline			Piling			Total
	Operating activities	$	(1,587	)	$	47,326		$	45,739
	Investing activities	—			182,836			182,836
	Financing activities	—			(271		)	(271		)
		$	(1,587	)	$	229,891		$	228,304

Stockbased_compensation_Tables

Stock-based compensation (Tables)	12 Months Ended
	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of stock-based compensation expenses included in general and administrative expenses	Stock-based compensation expenses included in general and administrative expenses are as follows:
	Year ended December 31,		2014				2013
	Share option plan (note 23(b))		$	921			$	981
	Liability classified restricted share unit plan (note 23(d(i)))		790				2,652
	Equity classified restricted share unit plan (note 23(d(ii)))		419				—
	Performance restricted share unit plan (note 23(e))		94				—
	Liability classified deferred stock unit plan (note 23(f(i)))		(1,100		)		2,560
	Equity classified deferred stock unit plan (note 23(f(ii)))		2,181				—
			$	3,305			$	6,193
Schedule of stock options activity
			Number of options			Weighted average
						exercise price
						$ per share
	Outstanding at December 31, 2012		3,029,734			5.7
	Granted		177,400			5.91
	Exercised(i)		(295,230	)		3.98
	Forfeited		(698,624	)		7.12
	Outstanding at December 31, 2013		2,213,280			5.51
	Exercised(i)		(385,880	)		3.49
	Forfeited		(61,480	)		7.83
	Outstanding at December 31, 2014		1,765,920			5.87
	(i)	All stock options exercised resulted in new common shares being issued (note 17(a));
Summary of information about stock options outstanding	The following table summarizes information about stock options outstanding at December 31, 2014:
			Options outstanding							Options exercisable
	Exercise price		Number			Weighted		Weighted		Number	Weighted	Weighted
						average		average exercise			average	average exercise
						remaining life		price			remaining life	price
	$2.75		373,760			7.5 years		$	2.75	109,760	7.5 years	$	2.75
	$2.79		450,000			7.5 years		$	2.79	—	—	$	—
	$3.69		38,900			3.9 years		$	3.69	38,900	3.9 years	$	3.69
	$4.90		40,000			7.3 years		$	4.9	16,000	7.3 years	$	4.9
	$5.00		142,760			1.3 years		$	5	142,760	1.3 years	$	5
	$5.91		166,600			9.0 years		$	5.91	33,320	9.0 years	$	5.91
	$6.56		94,560			6.9 years		$	6.56	55,120	6.9 years	$	6.56
	$8.28		60,000			4.5 years		$	8.28	60,000	4.5 years	$	8.28
	$8.58		30,000			5.7 years		$	8.58	24,000	5.7 years	$	8.58
	$9.33		71,580			5.1 years		$	9.33	59,840	5.1 years	$	9.33
	$10.13		68,860			6.0 years		$	10.13	56,120	6.0 years	$	10.13
	$13.21		75,000			3.0 years		$	13.21	75,000	3.0 years	$	13.21
	$13.50		76,140			2.9 years		$	13.5	76,140	2.9 years	$	13.5
	$16.46		50,000			3.3 years		$	16.46	50,000	3.3 years	$	16.46
	$16.75		27,760			1.7 years		$	16.75	27,760	1.7 years	$	16.75
			1,765,920			6.1 years		$	5.87	824,720	4.5 years	$	8.41
Schedule of restricted share unit plan activity
			Number of units
	Outstanding at December 31, 2012		1,110,275
	Granted		555,204
	Vested		(154,330	)
	Forfeited		(487,205	)
	Outstanding at December 31, 2013		1,023,944
	Dividend equivalents granted		695
	Vested		(350,271	)
	Forfeited		(58,865	)
	Outstanding at December 31, 2014		615,503
	Equity classified restricted share unit plan
			Number of units			Weighted average exercise price
						$ per share
	Outstanding at December 31, 2013		—			—
	Granted		274,256			7.98
	Dividend equivalents granted		11,557			6.15
	Vested		(605	)		7.75
	Forfeited		(22,300	)		7.87
	Outstanding at December 31, 2014		262,908			7.91
Senior executive stock option plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of assumptions used to value stock option grants	The weighted average assumptions used in estimating the fair value of the fully vested senior executive stock options as at December 31, 2014 and 2013 are as follows:
	Year ended December 31,		2014			2013
	Number of senior executive stock options		258,200			550,000
	Weighted average fair value per option granted ($)		0.08			1.71
	Weighted average assumptions:
	Dividend yield		2.2	%		N/A
	Expected volatility		49.68	%		39.12	%
	Risk-free interest rate		0.25	%		0.22	%
	Expected life (years)		0.4			1.4
Deferred share unit plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Schedule of stock plan activity	Liability classified deferred stock unit plan
			Number of units
	Outstanding at December 31, 2012		625,156
	Issued		141,509
	Redeemed		(179,831	)
	Outstanding at December 31, 2013		586,834
	Issued		7,674
	Redeemed		(63,886	)
	Outstanding at December 31, 2014		530,622
	Equity classified deferred stock unit plan
			Number of units			Weighted average exercise price
						$ per share
	Outstanding at December 31, 2013		—			—
	Issued		161,007			6.52
	Dividend equivalents granted		8,721			6.1
	Outstanding at December 31, 2014		169,728			6.5

Other_information_Tables

Other information (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Cash Flow Elements [Abstract]
Schedule of supplemental cash flow information	Supplemental cash flow information
	Year ended December 31,	2014			2013
	Cash paid during the year for:
	Interest	$	10,939		$	25,528
	Income taxes	—			91
	Cash received during the year for:
	Interest	63			256
	Income taxes	88			3,797
	Year ended December 31,	2014			2013
	Non-cash transactions:
	Addition of plant and equipment by means of capital leases	$	39,492		$	13,812
	Reclass from plant and equipment to assets held for sale	(1,321		)	(5,123		)
	Net increase in accounts payable related to purchase of plant and equipment	283			2,888
	Net increase in accounts payable related to purchase of intangibles	—			43
	Net decrease in accounts payable related to change in estimated financing fees	(101		)	—
	Net increase in accounts payable related to change in the lease inducement payable on the sublease	107			—
	Net decrease in short term portion of equipment lease liabilities included in accrued liabilities related to the purchase of plant and equipment	—			(159		)
	Net increase in long term portion of equipment lease liabilities related to the purchase of plant and equipment	—			1,702
	Net (decrease) increase in accrued liabilities related to current portion of RSU liability	(924		)	1,430
	Net increase (decrease) in accrued liabilities related to current portion of DSU liability	408			(253		)
	Net increase in accrued liabilities related to the current portion of the senior executive stock options	22			—
	Net increase in accrued liabilities related to dividend payable	697			—
Schedule of net change in non-cash working capital	Net change in non-cash working capital
	Year ended December 31,	2014			2013
	Operating activities:
	Accounts receivable, net	$	3,674		$	29,765
	Unbilled revenue	(11,454		)	30,275
	Inventories	(1,542		)	(644		)
	Prepaid expenses and deposits	(780		)	634
	Accounts payable	9,928			(31,847		)
	Accrued liabilities	(954		)	(1,603		)
	Long term portion of liabilities related to equipment leases	—			(209		)
	Billings in excess of costs incurred and estimated earnings on uncompleted contracts	(6,357		)	(872		)
		$	(7,485	)	$	25,499

Claims_revenue_Tables

Claims revenue (Tables)	12 Months Ended
	Dec. 31, 2014
Contractors [Abstract]
Schedule of claims revenue
	Year ended December 31,	2014		2013
	Claims revenue recognized	$	8,230	$	17,053
	Claims revenue uncollected (classified as unbilled revenue)	4,622		8,074

Significant_accounting_policie3

Significant accounting policies - Revenue Recognition (Details) (Minimum)	12 Months Ended
	Dec. 31, 2014
Minimum
Property, Plant and Equipment [Line Items]
Term of contract (less than one year)	1 year

Significant_accounting_policie4

Significant accounting policies - Property, Plant and Equipment (Details)	12 Months Ended
	Dec. 31, 2014
Other equipment | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Other equipment | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Licensed motor vehicles | Minimum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Licensed motor vehicles | Maximum
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Office and computer equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	4 years
Buildings
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years

Significant_accounting_policie5

Significant accounting policies - Intangible Assets (Details) (Capitalized computer software and development costs, Maximum)	12 Months Ended
	Dec. 31, 2014
Capitalized computer software and development costs | Maximum
Finite-Lived Intangible Assets [Line Items]
Intangible assets, useful life	4 years

Significant_accounting_policie6

Significant accounting policies - Stock-based Compensation (Details) (Restricted Share Unit (RSU))	12 Months Ended
	Dec. 31, 2014
Restricted Share Unit (RSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award service period	2 years
Award vesting period	3 years
Number of trading days used to determine weighted average trading price of common shares	5 days
Compensation expense recognition period	3 years

Accounts_receivable_Details

Accounts receivable (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Receivables [Abstract]
Accounts receivable b trade	54,733	59,309
Accounts receivable b holdbacks	10,741	9,055
Accounts receivable b other	1,029	1,813
Allowance for doubtful accounts (note 15(d))	0	0	-185
Total accounts receivable	66,503	70,177
Accounts receivable b holdback percentage	10.00%

Costs_incurred_and_estimated_e2

Costs incurred and estimated earnings net of billings on uncompleted contracts (Details) (CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Costs in excess of billings [Abstract]
Costs incurred and estimated earnings on uncompleted contracts	629,416	533,837
Less billings to date	-585,794	-508,026
Costs in excess of billings on uncompleted contracts	43,622	25,811
Contracts receivable [Abstract]
Unbilled revenue	43,622	32,168
Billings in excess of costs incurred and estimated earnings on uncompleted contracts	0	-6,357
Unbilled contracts receivable	43,622	25,811

Prepaid_expenses_and_deposits_1

Prepaid expenses and deposits (Details) (CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Current:
Prepaid insurance and deposits	968	1,076
Prepaid lease payments	537	880
Prepaid interest	748	196
Prepaid expenses and deposits	2,253	2,152
Long term:
Prepaid lease payments (note 11(a))	1,953	1,274

Assets_held_for_sale_Details

Assets held for sale (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Contract-related assets held for sale	29,400
Gain (loss) on disposal of assets held for sale	86	-2,212
Equipment
Property, Plant and Equipment [Line Items]
Gain (loss) on disposal of assets held for sale	86	-2,212
Equipment | Depreciation expense
Property, Plant and Equipment [Line Items]
Impairment of equipment assets held for sale	3,461	3,097

Income_taxes_Details

Income taxes (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
	provincial_jurisdiction
Operating Loss Carryforwards [Line Items]
Loss before income taxes	-728	-24,149
Tax rate	25.26%	25.26%
Expected benefit	-184	-6,101
(Decrease) increase related to:
Impact of enacted future statutory income tax rates	0	-209
Income tax adjustments and reassessments	-68	-249
Non deductible portion of capital losses	-72	69
Stock-based compensation	232	315
Other	61	73
Income tax benefit	-31	-6,102
Current income tax (benefit) expense	-92	-2,438
Deferred income tax benefit	61	-3,664
Deferred tax assets:
Non-capital losses	31,151	39,604
Deferred financing costs	1,135	1,709
Billings in excess of costs on uncompleted contracts	0	1,606
Capital lease obligations	16,148	10,914
Deferred lease inducements	64	91
Stock-based compensation	1,666	1,880
Other	481	409
Total deferred tax assets	50,645	56,213
Deferred tax liabilities:
Unbilled revenue and uncertified revenue included in accounts receivable	9,538	5,338
Assets held for sale	6,466	13
Accounts receivable b holdbacks	3,084	2,308
Property, plant and equipment	58,134	56,945
Deferred partnership income	0	18,125
Total deferred tax liabilities	77,222	82,729
Net deferred income tax liability	-26,577	-26,516
Net deferred tax liability classification
Current asset	5,609	3,678
Long term asset	29,947	27,660
Current liability	-20,056	-8,036
Long term liability	-42,077	-49,818
Net deferred income tax liability	-26,577	-26,516
Number of provincial jurisdictions	3
Number of Additional Provincial Income Taxing Jurisdictions, Prior to Disposal	2
Operating loss carryforwards	123,307
2026
Net deferred tax liability classification
Operating loss carryforwards	283
2027
Net deferred tax liability classification
Operating loss carryforwards	0
2028
Net deferred tax liability classification
Operating loss carryforwards	0
2029
Net deferred tax liability classification
Operating loss carryforwards	1
2030
Net deferred tax liability classification
Operating loss carryforwards	5,334
2031
Net deferred tax liability classification
Operating loss carryforwards	18,567
2032
Net deferred tax liability classification
Operating loss carryforwards	48,910
2033
Net deferred tax liability classification
Operating loss carryforwards	34,788
2034
Net deferred tax liability classification
Operating loss carryforwards	15,424
Capital loss carryforward
Net deferred tax liability classification
Valuation allowance, amount	962	962

Plant_and_equipment_Details

Plant and equipment (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Cost	434,435	466,971
Accumulated Deprecation	173,537	188,996
Net Book Value	260,898	277,975
Addition of plant and equipment by means of capital leases	39,492	13,812
Heavy equipment
Property, Plant and Equipment [Line Items]
Cost	142,052	251,872
Accumulated Deprecation	42,292	96,038
Net Book Value	99,760	155,834
Major component parts in use
Property, Plant and Equipment [Line Items]
Cost	112,645	60,484
Accumulated Deprecation	55,895	23,472
Net Book Value	56,750	37,012
Other equipment
Property, Plant and Equipment [Line Items]
Cost	41,739	27,594
Accumulated Deprecation	18,758	11,511
Net Book Value	22,981	16,083
Licensed motor vehicles
Property, Plant and Equipment [Line Items]
Cost	24,247	25,911
Accumulated Deprecation	20,763	22,474
Net Book Value	3,484	3,437
Office and computer equipment
Property, Plant and Equipment [Line Items]
Cost	9,355	13,846
Accumulated Deprecation	8,216	11,882
Net Book Value	1,139	1,964
Buildings
Property, Plant and Equipment [Line Items]
Cost	2,791	4,691
Accumulated Deprecation	2,606	2,650
Net Book Value	185	2,041
Leasehold improvements
Property, Plant and Equipment [Line Items]
Cost		9,946
Accumulated Deprecation		6,187
Net Book Value		3,759
Assets under capital lease
Property, Plant and Equipment [Line Items]
Cost	101,606	72,627
Accumulated Deprecation	25,007	14,782
Net Book Value	76,599	57,845
Depreciation expense	12,108	6,694

Other_assets_Details

Other assets (Details) (CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid lease payments	1,953	1,274
Intangible assets	4,385	7,043
Deferred financing costs	2,205	3,813
Deferred lease inducement	1,212	0
Total other assets, noncurrent	9,755	12,130

Other_assets_Intangible_assets

Other assets - Intangible assets (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Cost	17,102	22,713
Accumulated Amortization	12,717	15,670
Net Book Value	4,385	7,043
Internally developed computer software capitalized during the period	990	2,826
Internally development computer software disposed of during period	6,601	0
Amortization of intangible assets	3,648	3,276
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
2015	1,815
2016	1,410
2017	781
2018	379
Net Book Value	4,385	7,043

Other_assets_Deferred_financin

Other assets - Deferred financing costs (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred financing costs [Abstract]
Cost	15,522	15,536
Accumulated Amortization	13,317	11,723
Net Book Value	2,205	3,813
Amortization of deferred financing costs	1,594	4,326
Interest expense
Deferred financing costs [Abstract]
Amortization of deferred financing costs	1,594	4,326
Revolving Facilities | Credit facilities
Deferred financing costs [Abstract]
Cost	6,878	6,881
Accumulated Amortization	6,347	5,994
Net Book Value	531	887
Financing fees incurred in connection with debt modification	87	1,020
Prior period change in financing fees	90
Series 1 Debentures | Corporate debentures
Deferred financing costs [Abstract]
Cost	8,644	8,655
Accumulated Amortization	6,970	5,729
Net Book Value	1,674	2,926
Financing fees incurred in connection with debt issuance	0	1,769
Prior year change in estimated financing fees	11
Unamortized deferred financing costs expensed upon redemption of notes	534	2,737

Other_assets_Deferred_lease_in

Other assets - Deferred lease inducements asset (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Deferred Lease Inducements Asset [Roll Forward]
Balance, beginning of year	0	0
Additions	1,307	0
Amortization of deferred lease inducements	-95	0
Balance, end of year	1,212	0

Accrued_liabilities_Details

Accrued liabilities (Details) (CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Payables and Accruals [Abstract]
Accrued interest payable	1,514	1,836
Payroll liabilities	9,845	11,970
Liabilities related to equipment leases	786	190
Current portion of deferred gain on sale leaseback (note 16(d))	93	0
Dividends payable (note 17(d))	697	0
Income and other taxes payable	2,062	1,659
Accrued liabilities	14,997	15,655

Long_term_debt_Details

Long term debt (Details) (CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Long-term debt	64,269	75,000
Credit Facility
Debt Instrument [Line Items]
Long-term debt	5,536	0
Corporate debentures
Debt Instrument [Line Items]
Long-term debt	58,733	75,000

Long_term_debt_Credit_faciliti

Long term debt - Credit facilities (Details) (CAD)	0 Months Ended
	Sep. 10, 2014	Dec. 31, 2013	Dec. 31, 2014
			tranche
Line of Credit Facility [Line Items]
Covenant terms, maximum senior leverage ratio	2.5	2
Capital lease debt
Line of Credit Facility [Line Items]
Increase in borrowing capacity, amount	15,000,000
Maximum borrowing capacity of credit facility	90,000,000
Revolving Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity of credit facility			85,000,000
Number of tranches			2
Unused borrowing availability under the revolving facility		60,000,000	54,500,000
Tranche A | Revolving Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity of credit facility			60,000,000
Outstanding borrowings under credit facilities		0	5,500,000
Tranche B | Revolving Facility
Line of Credit Facility [Line Items]
Unused borrowing availability under the revolving facility			25,000,000
Tranche B | Letters of credit
Line of Credit Facility [Line Items]
Outstanding borrowings under credit facilities		3,100,000	5,100,000
Corporate debentures | Series 1 Debentures
Line of Credit Facility [Line Items]
Approved redemption amount	20,000,000

Long_term_debt_Series_1_Debent

Long term debt - Series 1 Debentures (Details) (CAD)	0 Months Ended			12 Months Ended
	Dec. 22, 2014	Apr. 08, 2014	Feb. 28, 2014	Dec. 31, 2014	Dec. 31, 2013	Apr. 07, 2010
Debt Instrument [Line Items]
Gain (loss) on debt extinguishment				-54,000	-6,476,000
Corporate debentures | Series 1 Debentures
Debt Instrument [Line Items]
Face amount of long term debt						225,000,000
Stated interest rate on long term debt						9.13%
Redemption price as a percentage of the principal amount			103.04%
Redemption premium upon a change of control						101.00%
Amount of debt elected to be redeemed			10,000,000
Redemption amount of Series 1 Debentures	6,300,000	10,000,000			150,000,000
Redemption price per $1,000 principal notes	960
Redemption price, threshold amount	1,000
Accrued and unpaid interest				100,000	5,300,000
Gain (loss) on debt extinguishment		300,000		-300,000	-6,500,000
Corporate debentures | Series 1 Debentures | On or after April 7, 2014
Debt Instrument [Line Items]
Redemption price as a percentage of the principal amount				103.04%
Corporate debentures | Series 1 Debentures | On or after April 7, 2015
Debt Instrument [Line Items]
Redemption price as a percentage of the principal amount				101.52%
Corporate debentures | Series 1 Debentures | On or after April 7, 2016
Debt Instrument [Line Items]
Redemption price as a percentage of the principal amount				100.00%

Capital_lease_obligations_Deta

Capital lease obligations (Details) (CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Capital Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	25,115
2016	21,149
2017	11,662
2018	10,179
2019	1,778
Subtotal:	69,883
Less: amount representing interest	-5,828
Present value of minimum lease payments	64,055
Less: current portion	-22,201	-14,996
Long term portion	41,854	28,299

Financial_instruments_and_risk2

Financial instruments and risk management - Financial instruments (Details) (CAD)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Carrying Amount
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Capital lease obligations	64,055,000	[1]	43,295,000	[1]
Series 1 Debentures	58,733,000	[2]	75,000,000	[2]
Fair Value
Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]
Capital lease obligations	58,951,000	[1]	39,508,000	[1]
Series 1 Debentures	58,733,000	[2]	77,813,000	[2]
Credit facilities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Outstanding balance, long-term debt	5,500,000		0
Change in basis spread on variable rate	100.00%
Change in annual interest expense due to interest rate change	100,000
[1]	The fair values of amounts due under capital leases are based on management estimates which are determined by discounting cash flows required under the instruments at the interest rates currently estimated to be available for instruments with similar terms.
[2]	The fair value of the Series 1 Debentures is based upon the expected discounted cash flows and the period end market price of similar financial instruments.

Financial_instruments_and_risk3

Financial instruments and risk management - Assets held-for-sale (Details) (Non-recurring basis, Level 3, CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Carrying Amount
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for sale	29,589	52
Change in Fair Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets held for sale	-3,461	-3,097

Financial_instruments_and_risk4

Financial instruments and risk management - Risk management (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Concentration Risk [Line Items]
General payment terms	30 days
Customer A | Total revenues | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	29.00%	0.00%
Customer A | Accounts receivable and unbilled revenue | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	49.00%	0.00%
Customer B | Total revenues | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	28.00%	29.00%
Customer B | Accounts receivable and unbilled revenue | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	26.00%	28.00%
Customer C | Total revenues | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	14.00%	22.00%
Customer C | Accounts receivable and unbilled revenue | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%	17.00%
Customer D | Total revenues | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	11.00%	8.00%
Customer D | Accounts receivable and unbilled revenue | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	0.00%	26.00%
Customer E | Total revenues | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	6.00%	10.00%
Customer F | Total revenues | Major customers
Concentration Risk [Line Items]
Concentration risk, percentage	1.00%	18.00%

Financial_instruments_and_risk5

Financial instruments and risk management - Maximum credit exposure (Details) (CAD)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Unbilled revenue	43,622	32,168
Maximum exposure to credit risk
Fair Value, Concentration of Risk, Financial Statement Captions [Line Items]
Trade accounts receivables	65,474	68,364
Other receivables	1,029	1,813
Total accounts receivable	66,503	70,177
Unbilled revenue	43,622	32,168

Financial_instruments_and_risk6

Financial instruments and risk management - Trade receivables (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]
Not past due	60,543	59,337
Past due 1-30 days	3,658	3,948
Past due 31-60 days	2	1,538
More than 61 days	1,271	3,541
Total	65,474	68,364
Allowance for Doubtful Accounts Receivable [Roll Forward]
Opening balance	0	185
Current year allowance	164	365
Write-offs	-164	0
Discontinued operations	0	-550
Ending balance	0	0

Other_long_term_obligations_De

Other long term obligations (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Other Liabilities, Noncurrent [Abstract]
Deferred lease inducements	252	359
Asset retirement obligation	562	512
Deferred gain on sale leaseback (note 16(d))	371	0
Other obligations, current and noncurrent	4,991	9,140
Less current portion of:
Deferred gain on sale leaseback	-93	0
Other obligations, noncurrent portion	3,459	7,207
Lease Incentive, Payable [Roll Forward]
Balance, beginning of year	359	466
Amortization of deferred lease inducements	-107	-107
Balance, end of year	252	359
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance, beginning of year	512	466
Accretion expense	50	46
Balance, end of year	562	512
Estimated undiscounted cash flows required to settle obligation	1,084	1,084
Credit adjusted risk-free rate assumed in measuring the asset retirement obligation (percent)	9.42%
Deferred Gain on Sale Leaseback [Roll Forward]
Balance, beginning of year	0	0
Addition	371	0
Balance, end of year	371	0
Stock options | Senior executive stock option plan
Other Liabilities, Noncurrent [Abstract]
Deferred compensation plans	22	940
Less current portion of:
Deferred compensation plans, current	-22	0
Restricted share units (RSUs) | Restricted share unit plan
Other Liabilities, Noncurrent [Abstract]
Deferred compensation plans	1,779	3,667
Less current portion of:
Deferred compensation plans, current	-1,009	-1,933
Deferred stock units (DSUs) | Directors' deferred share unit plan
Other Liabilities, Noncurrent [Abstract]
Deferred compensation plans	2,005	3,662
Less current portion of:
Deferred compensation plans, current	-408	0

Shares_Common_stock_issued_and

Shares - Common stock issued and outstanding (Details) (CAD)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, issued (shares)	34,746,236		36,251,006
Beginning balance, outstanding (shares)	34,746,236		36,251,006
Issued upon exercise of stock options (shares)			295,230
Purchase of treasury shares for settlement of certain equity classified stock-based compensation	-589,892
Retired through Share Purchase Program (shares)	-500,000		-1,800,000
Ending balance, issued (shares)	34,923,916		34,746,236
Ending balance, outstanding (shares)	34,334,024		34,746,236
Earnings Per Share [Abstract]
Net loss from continuing operations	-697		-18,047
Net (loss) income from discontinued operations	-472		87,231
Net (loss) income	-1,169		69,184
Weighted average number of shares outstanding, basic
Weighted average number of common shares (in shares)	35,014,418		36,269,996
Basic per share information
Net loss from continuing operations (in CAD per share)	-0.02		-0.5
Net (loss) income from discontinued operations	-0.01		2.41
Net income (loss) (in CAD per share)	-0.03		1.91
Dilutive effect of stock options (in shares)	0		342,957
Weighted average number of shares outstanding, diluted
Weighted average number of diluted common shares (in shares)	35,014,418		36,612,953
Diluted per share information
Net loss from continuing operations (in CAD per share)	-0.02		-0.5
Net (loss) income from discontinued operations	-0.01		2.39
Net income (loss) (in CAD per share)	-0.03		1.89
Share option plan
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issued upon exercise of stock options (shares)	385,880	[1]	295,230	[1]
Senior executive stock option plan
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issued upon exercise of stock options (shares)	291,800		0
Treasury shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, outstanding (shares)	0
Purchase of treasury shares for settlement of certain equity classified stock-based compensation	-589,892
Ending balance, outstanding (shares)	-589,892
[1]	All stock options exercised resulted in new common shares being issued (note 17(a))

Shares_Antidilutive_securities

Shares - Antidilutive securities (Details) (Stock options)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Stock options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive awards not considered in computing diluted earnings per share	1,765,920	863,414

Shares_Share_Purchase_Program_

Shares - Share Purchase Program (Details) (CAD)	0 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 18, 2014	Dec. 31, 2014	Dec. 31, 2013
Equity, Class of Treasury Stock [Line Items]
Retired through Share Purchase Program (shares)		500,000	1,800,000
Stock purchase program
Equity, Class of Treasury Stock [Line Items]
Retired through Share Purchase Program (shares)	1,771,195
Percentage of issued and outstanding common shares purchased under Purchase Program	5.00%
Shares retired during period		500,000	1,800,000
Shares retired during period, percentage of issued and outstanding shares			5.00%
Common stock | Stock purchase program
Equity, Class of Treasury Stock [Line Items]
Increase (decrease) as a result of the retirement of shares		-4,238	-16,133
Additional paid in capital | Stock purchase program
Equity, Class of Treasury Stock [Line Items]
Increase (decrease) as a result of the retirement of shares		2,297	4,393

Shares_Dividends_Details

Shares - Dividends (Details) (CAD)	0 Months Ended			12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Oct. 21, 2014	Jul. 21, 2014	Apr. 21, 2014	Dec. 31, 2014	Feb. 19, 2014
Equity [Abstract]
Annual aggregate dividend (CAD per share)					0.08
Dividends paid (CAD per share)	0.02	0.02	0.02	0.02
Dividends payable				697

Commitments_Details

Commitments (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2015	5,068
2016	4,214
2017	3,980
2018	4,013
2019 and thereafter	15,357
Total future minimum lease payments for operating leases	32,632
Contingent rentals on operating leases usage (recovery) charges in excess of minimum contracted amounts	2,116	-249

Subsequent_events_Details

Subsequent events (Details) (Subsequent event, CAD)	Jan. 02, 2015
In Thousands, unless otherwise specified
Subsequent event
Subsequent Event [Line Items]
Net proceeds from sale of contract-related assets	36,347

Interest_expense_Details

Interest expense (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule of Interest Expense [Line Items]
Amortization of deferred financing costs	1,594	4,326
Interest on long term debt	12,133	21,973
Other interest expense (income)	102	-276
Total interest expense, net	12,235	21,697
Capital lease obligations
Schedule of Interest Expense [Line Items]
Interest on long term debt	3,103	2,716
Credit Facility
Schedule of Interest Expense [Line Items]
Interest on long term debt	1,268	2,424
Corporate debentures | Series 1 Debentures
Schedule of Interest Expense [Line Items]
Interest on long term debt	6,168	12,507

Discontinued_operations_Detail

Discontinued operations (Details) (CAD)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
	business
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of businesses disposed of in prior years	2
Costs related to discontinued operations during period	-472,000	87,231,000
Results of discontinued operations
Revenue		98,735,000
Project costs		80,793,000
Equipment costs		1,242,000
Depreciation		706,000
Gross (loss) profit		15,994,000
General and administrative expenses		7,169,000
Loss (gain) on disposal of assets and liabilities		-98,002,000
Gain on sale of inventory		-46,000
Amortization of intangible assets		351,000
Operating (loss) income		106,522,000
Interest expense		4,758,000
(Loss) income before income taxes		101,764,000
Current income tax expense		164,000
Deferred income tax (benefit) expense		14,369,000
Net (loss) income		87,231,000
Cash provided by (used in) the discontinued operations
Operating activities	-472,000	45,739,000
Investing activities	0	182,836,000
Financing activities	0	-271,000
Total cash provided by (used in) discontinued operations	-472,000	228,304,000
Pipeline
Results of discontinued operations
Revenue		0
Project costs		1,321,000
Equipment costs		0
Depreciation		0
Gross (loss) profit		-1,321,000
General and administrative expenses		312,000
Loss (gain) on disposal of assets and liabilities		63,000
Gain on sale of inventory		-46,000
Amortization of intangible assets		0
Operating (loss) income		-1,650,000
Interest expense		0
(Loss) income before income taxes		-1,650,000
Current income tax expense		0
Deferred income tax (benefit) expense		-510,000
Net (loss) income		-1,140,000
Cash provided by (used in) the discontinued operations
Operating activities		-1,587,000
Investing activities		0
Financing activities		0
Total cash provided by (used in) discontinued operations		-1,587,000
Piling
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Period to receive contingent consideration as part of sale	3 years
Results of discontinued operations
Revenue		98,735,000
Project costs		79,472,000
Equipment costs		1,242,000
Depreciation		706,000
Gross (loss) profit		17,315,000
General and administrative expenses		6,857,000
Loss (gain) on disposal of assets and liabilities		-98,065,000
Gain on sale of inventory		0
Amortization of intangible assets		351,000
Operating (loss) income		108,172,000
Interest expense		4,758,000
(Loss) income before income taxes		103,414,000
Current income tax expense		164,000
Deferred income tax (benefit) expense		14,879,000
Net (loss) income		88,371,000
Cash provided by (used in) the discontinued operations
Operating activities		47,326,000
Investing activities		182,836,000
Financing activities		-271,000
Total cash provided by (used in) discontinued operations		229,891,000
Maximum | Piling
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Contingent consideration, additional proceeds	92,500

Stockbased_compensation_Stockb

Stock-based compensation - Stock-based compensation expenses (Details) (General and administrative expenses, CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	3,305	6,193
Share option plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	921	981
Liability classified restricted share unit plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	790	2,652
Equity classified restricted share unit plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	419	0
Performance restricted share unit plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	94	0
Liability classified deferred stock unit plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	-1,100	2,560
Equity classified deferred stock unit plan
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation expenses	2,181	0

Stockbased_compensation_Plan_a

Stock-based compensation - Plan activity (Details) (CAD)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Exercised (options)			-295,230
Share option plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance (options)	2,213,280		3,029,734
Granted (options)			177,400
Exercised (options)	-385,880	[1]	-295,230	[1]
Forfeited (options)	-61,480		-698,624
Ending balance (options)	1,765,920		2,213,280
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Beginning balance (CAD per share)	5.51		5.7
Granted (CAD per share)			5.91
Exercised (CAD per share)	3.49	[1]	3.98	[1]
Forfeited (CAD per share)	7.83		7.12
Ending balance (CAD per share)	5.87		5.51
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Number of options granted			177,400
Senior executive stock option plan
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Granted (options)	258,200		550,000
Exercised (options)	-291,800		0
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Number of options granted	258,200		550,000
Weighted average fair value per option granted (CAD per share)	0.08		1.71
Senior executive stock option plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Dividend yield	2.20%
Expected volatility	49.68%		39.12%
Risk-free interest rate	0.25%		0.22%
Expected life (years)	0 years 5 months		1 year 5 months
Liability classified restricted share unit plan | Restricted share units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (units)	1,023,944		1,110,275
Granted/issued (units)			555,204
Dividend equivalents granted/issued (units)	695
Vested (units)	-350,271		-154,330
Forfeited (units)	-58,865		-487,205
Ending balance (units)	615,503		1,023,944
Equity classified restricted share unit plan | Restricted share units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (units)	0
Granted/issued (units)	274,256
Dividend equivalents granted/issued (units)	11,557
Vested (units)	-605		0
Forfeited (units)	-22,300
Ending balance (units)	262,908		0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding, beginning of period (CAD per unit)	0
Granted/Issued, Weighted average exercise price (CAD per unit)	7.98
Dividend equivalents granted/issued, Weighted average exercise price (CAD per unit)	6.15
Vested, Weighted average exercise price (CAD per unit)	7.75
Forfeited, Weighted average exercise price (CAD per unit)	7.87
Outstanding, end of period (CAD per unit)	7.91		0
Liability classified deferred stock unit plan | Deferred stock units (DSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (units)	586,834		625,156
Granted/issued (units)	7,674		141,509
Vested (units)	-63,886		-179,831
Ending balance (units)	530,622		586,834
Equity classified deferred stock unit plan | Deferred stock units (DSUs)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance (units)	0
Granted/issued (units)	161,007
Dividend equivalents granted/issued (units)	8,721
Ending balance (units)	169,728
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Outstanding, beginning of period (CAD per unit)	0
Granted/Issued, Weighted average exercise price (CAD per unit)	6.52
Dividend equivalents granted/issued, Weighted average exercise price (CAD per unit)	6.1
Outstanding, end of period (CAD per unit)	6.5
[1]	All stock options exercised resulted in new common shares being issued (note 17(a))

Stockbased_compensation_Option

Stock-based compensation - Options by exercise price range (Details) (Share option plan, CAD)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Number of options outstanding	1,765,920
Options outstanding, weighted average remaining life	6 years 1 month	6 years 11 months
Options outstanding, weighted average exercise price	5.87
Number of options exercisable	824,720	892,700
Options exercisable, weighted average remaining life	4 years 6 months
Options exercisable, weighted average exercise price	8.41	8
$2.75
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	2.75
Number of options outstanding	373,760
Options outstanding, weighted average remaining life	7 years 6 months
Options outstanding, weighted average exercise price	2.75
Number of options exercisable	109,760
Options exercisable, weighted average remaining life	7 years 5 months 18 days
Options exercisable, weighted average exercise price	2.75
$2.79
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	2.79
Number of options outstanding	450,000
Options outstanding, weighted average remaining life	7 years 6 months 12 days
Options outstanding, weighted average exercise price	2.79
Number of options exercisable	0
Options exercisable, weighted average exercise price	0
$3.69
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	3.69
Number of options outstanding	38,900
Options outstanding, weighted average remaining life	3 years 10 months 24 days
Options outstanding, weighted average exercise price	3.69
Number of options exercisable	38,900
Options exercisable, weighted average remaining life	3 years 11 months
Options exercisable, weighted average exercise price	3.69
$4.90
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	4.9
Number of options outstanding	40,000
Options outstanding, weighted average remaining life	7 years 3 months
Options outstanding, weighted average exercise price	4.9
Number of options exercisable	16,000
Options exercisable, weighted average remaining life	7 years 3 months
Options exercisable, weighted average exercise price	4.9
$5.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	5
Number of options outstanding	142,760
Options outstanding, weighted average remaining life	1 year 3 months 18 days
Options outstanding, weighted average exercise price	5
Number of options exercisable	142,760
Options exercisable, weighted average remaining life	1 year 3 months
Options exercisable, weighted average exercise price	5
$5.91
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	5.91
Number of options outstanding	166,600
Options outstanding, weighted average remaining life	9 years
Options outstanding, weighted average exercise price	5.91
Number of options exercisable	33,320
Options exercisable, weighted average remaining life	9 years
Options exercisable, weighted average exercise price	5.91
$6.56
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	6.56
Number of options outstanding	94,560
Options outstanding, weighted average remaining life	6 years 11 months
Options outstanding, weighted average exercise price	6.56
Number of options exercisable	55,120
Options exercisable, weighted average remaining life	6 years 11 months
Options exercisable, weighted average exercise price	6.56
$8.28
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	8.28
Number of options outstanding	60,000
Options outstanding, weighted average remaining life	4 years 6 months
Options outstanding, weighted average exercise price	8.28
Number of options exercisable	60,000
Options exercisable, weighted average remaining life	4 years 6 months
Options exercisable, weighted average exercise price	8.28
$8.58
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	8.58
Number of options outstanding	30,000
Options outstanding, weighted average remaining life	5 years 8 months
Options outstanding, weighted average exercise price	8.58
Number of options exercisable	24,000
Options exercisable, weighted average remaining life	5 years 8 months
Options exercisable, weighted average exercise price	8.58
$9.33
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	9.33
Number of options outstanding	71,580
Options outstanding, weighted average remaining life	5 years 1 month
Options outstanding, weighted average exercise price	9.33
Number of options exercisable	59,840
Options exercisable, weighted average remaining life	5 years 1 month
Options exercisable, weighted average exercise price	9.33
$10.21
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	10.13
Number of options outstanding	68,860
Options outstanding, weighted average remaining life	6 years
Options outstanding, weighted average exercise price	10.13
Number of options exercisable	56,120
Options exercisable, weighted average remaining life	6 years
Options exercisable, weighted average exercise price	10.13
$13.21
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	13.21
Number of options outstanding	75,000
Options outstanding, weighted average remaining life	3 years
Options outstanding, weighted average exercise price	13.21
Number of options exercisable	75,000
Options exercisable, weighted average remaining life	3 years
Options exercisable, weighted average exercise price	13.21
$13.50
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	13.5
Number of options outstanding	76,140
Options outstanding, weighted average remaining life	2 years 11 months
Options outstanding, weighted average exercise price	13.5
Number of options exercisable	76,140
Options exercisable, weighted average remaining life	2 years 11 months
Options exercisable, weighted average exercise price	13.5
$16.46
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	16.46
Number of options outstanding	50,000
Options outstanding, weighted average remaining life	3 years 3 months
Options outstanding, weighted average exercise price	16.46
Number of options exercisable	50,000
Options exercisable, weighted average remaining life	3 years 3 months
Options exercisable, weighted average exercise price	16.46
$16.75
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price (CAD per share)	16.75
Number of options outstanding	27,760
Options outstanding, weighted average remaining life	1 year 8 months
Options outstanding, weighted average exercise price	16.75
Number of options exercisable	27,760
Options exercisable, weighted average remaining life	1 year 8 months
Options exercisable, weighted average exercise price	16.75

Stockbased_compensation_Textua

Stock-based compensation - Textuals (Details) (CAD)	12 Months Ended				0 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Sep. 22, 2010	Jul. 01, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from stock options exercised	2,807		1,175
Shares exercised and settled during period			295,230
Share option plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number shares acquired per each option exercised	1
Stock options annual vesting percentage	20.00%
Proceeds from stock options exercised	1,348		1,175
Total intrinsic value of options exercised	1,711		524
Options outstanding, weighted average remaining life	6 years 1 month		6 years 11 months
Fair value of options vested during the year	983		1,278
Number of options exercisable	824,720		892,700
Options exercisable, weighted average exercise price	8.41		8
Total compensation costs related to non-vested awards not yet recognized	1,223		1,762
Shares exercised and settled during period	385,880	[1]	295,230	[1]
Share option plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Years from grant date stock options expire	10 years
Total compensation costs related to non-vested awards not yet recognized, weighted average recognition period	2 years 6 months		3 years 2 months 12 days
Senior executive stock option plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Proceeds from stock options exercised	1,459		0
Total intrinsic value of options exercised	935		0
Stock options reclassified from equity to a long-term liability					550,000
Shares exercised and settled during period	291,800		0
Senior executive stock option plan | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Current portion of award obligation	22		0
Non-current portion of award obligation	0		940
Liability classified restricted share unit plan | Restricted share units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Service period of award subsequent to year of grant	2 years
Award vesting period	3 years
Award units settled during the period (units)	350,271		154,330
Award units settled during the period	2,678		727
Weighted average remaining contractual life of award	0 years 9 months		1 year 4 months
Fair market value (CAD per share)	3.78		6.24
Total unrecognized compensation costs related to non-vested share-based payment arrangements	641		2,958
Liability classified restricted share unit plan | Restricted share units (RSUs) | Accrued liabilities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Current portion of award obligation	1,009		1,933
Liability classified restricted share unit plan | Restricted share units (RSUs) | Other long-term liabilities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-current portion of award obligation	770		1,734
Equity classified restricted share unit plan | Restricted share units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award units settled during the period (units)	605		0
Weighted average remaining contractual life of award	2 years 4 months
Total unrecognized compensation costs related to non-vested share-based payment arrangements	1,276		0
Performance restricted share unit plan | Performance restricted share units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation costs related to non-vested awards not yet recognized	468
Total compensation costs related to non-vested awards not yet recognized, weighted average recognition period	2 years 6 months
Award vesting period						3 years
Fair value of awards granted on July 1, 2014						563
Deferred share unit plan | Deferred stock units (DSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of non-officer directors' fixed remuneration in the form of DDSUs (50% or more)	50.00%
Liability classified deferred stock unit plan | Deferred stock units (DSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award units settled during the period (units)	63,886		179,831
Award units settled during the period	557		968
Fair market value (CAD per share)	3.78		6.24
Liability classified deferred stock unit plan | Deferred stock units (DSUs) | Accrued liabilities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Current portion of award obligation	408		0
Liability classified deferred stock unit plan | Deferred stock units (DSUs) | Other long-term liabilities
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-current portion of award obligation	1,597		3,662
[1]	All stock options exercised resulted in new common shares being issued (note 17(a))

Other_information_Details

Other information (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Cash paid during the year for:
Interest	10,939	25,528
Income taxes	0	91
Cash received during the year for:
Interest	63	256
Income taxes	88	3,797
Non-cash transactions:
Addition of plant and equipment by means of capital leases	39,492	13,812
Reclass from plant and equipment to assets held for sale	-1,321	-5,123
Net increase in accounts payable related to purchase of plant and equipment	0	43
Net decrease in accounts payable related to change in estimated financing fees	-101	0
Net increase in accounts payable related to change in the lease inducement payable on the sublease	107	0
Net increase in accrued liabilities related to dividend payable	697	0
Change in non-cash working capital related to piling discontinued operations, excluded from non-cash working capital for continuing operations:
Accounts receivable, net	3,674	29,765
Unbilled revenue	-11,454	30,275
Inventories	-1,542	-644
Prepaid expenses and deposits	-780	634
Accounts payable	9,928	-31,847
Accrued liabilities	-954	-1,603
Long term portion of liabilities related to equipment leases	0	-209
Billings in excess of costs incurred and estimated earnings on uncompleted contracts	-6,357	-872
Net changes in non-cash working capital	-7,485	25,499
Purchase of property, plant and equipment
Non-cash transactions:
Net increase in accounts payable related to purchase of plant and equipment	283	2,888
Net decrease in short term portion of equipment lease liabilities included in accrued liabilities related to the purchase of plant and equipment	0	-159
Net increase in long term portion of equipment lease liabilities related to the purchase of plant and equipment	0	1,702
Restricted share units (RSUs) | Restricted share unit plan
Non-cash transactions:
Net change in accrued liabilities related to current portion of plan liabilities	-924	1,430
Deferred stock units (DSUs) | Directors' deferred share unit plan
Non-cash transactions:
Net change in accrued liabilities related to current portion of plan liabilities	408	-253
Stock options | Senior executive stock option plan
Non-cash transactions:
Net change in accrued liabilities related to current portion of plan liabilities	22	0
Continuing operations
Non-cash transactions:
Addition of plant and equipment by means of capital leases	39,492	13,812

Claims_revenue_Details

Claims revenue (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Contractors [Abstract]
Claims revenue recognized	8,230	17,053
Claims revenue uncollected (classified as unbilled revenue)	4,622	8,074

Employee_benefit_plans_Details

Employee benefit plans (Details) (CAD)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]
Company match of voluntary contributions made by employees, percentage of base salary	5.00%
Contributions made by the Company during the year	1,215	1,565