Segment Reporting - Summarized Operating Results and Certain Financial Position Data of Company's Reportable Business Segments (Detail) (USD $)	3 Months Ended
Apr. 30, 2015	Apr. 30, 2014	Jan. 31, 2015
Segment Reporting Information [Line Items]
Revenues	$ 85,488,000us-gaap_ContractsRevenue	$ 51,191,000us-gaap_ContractsRevenue
Cost of revenues	64,321,000us-gaap_CostOfServices	41,140,000us-gaap_CostOfServices
Gross profit	21,167,000us-gaap_GrossProfit	10,051,000us-gaap_GrossProfit
Selling, general and administrative expenses	5,540,000	3,379,000
Income (loss) from operations	15,627,000us-gaap_OperatingIncomeLoss	6,672,000us-gaap_OperatingIncomeLoss
Other income, net	85,000us-gaap_OtherNonoperatingIncomeExpense	22,000us-gaap_OtherNonoperatingIncomeExpense
INCOME BEFORE INCOME TAXES	15,712,000	6,694,000
Income tax expense	4,861,000us-gaap_IncomeTaxExpenseBenefit	1,894,000us-gaap_IncomeTaxExpenseBenefit
Net income	10,851,000us-gaap_ProfitLoss	4,800,000us-gaap_ProfitLoss
Amortization of purchased intangibles	60,000us-gaap_AmortizationOfIntangibleAssets	60,000us-gaap_AmortizationOfIntangibleAssets
Depreciation	119,000us-gaap_Depreciation	142,000us-gaap_Depreciation
Property, plant and equipment additions	1,207,000	85,000
Goodwill	18,476,000us-gaap_Goodwill	18,476,000us-gaap_Goodwill	18,476,000us-gaap_Goodwill
Total assets	399,872,000us-gaap_Assets	372,317,000us-gaap_Assets	391,193,000us-gaap_Assets
Power Industry Services [Member]
Segment Reporting Information [Line Items]
Revenues	82,884,000	49,824,000
Cost of revenues	62,379,000	40,049,000
Telecommunications Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Revenues	2,604,000	1,367,000
Cost of revenues	1,942,000	1,091,000
Operating Segments [Member] \| Power Industry Services [Member]
Segment Reporting Information [Line Items]
Revenues	82,884,000	49,824,000
Cost of revenues	62,379,000	40,049,000
Gross profit	20,505,000	9,775,000
Selling, general and administrative expenses	3,583,000	1,787,000
Income (loss) from operations	16,922,000	7,988,000
Other income, net	79,000	21,000
INCOME BEFORE INCOME TAXES	17,001,000	8,009,000
Amortization of purchased intangibles	60,000	60,000
Depreciation	75,000	96,000
Property, plant and equipment additions	1,126,000	28,000
Goodwill	18,476,000	18,476,000
Total assets	334,355,000	331,560,000
Operating Segments [Member] \| Telecommunications Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Revenues	2,604,000	1,367,000
Cost of revenues	1,942,000	1,091,000
Gross profit	662,000	276,000
Selling, general and administrative expenses	304,000	352,000
Income (loss) from operations	358,000	(76,000)
INCOME BEFORE INCOME TAXES	358,000	(76,000)
Depreciation	41,000	44,000
Property, plant and equipment additions	81,000	7,000
Total assets	4,424,000	2,118,000
Other [Member]
Segment Reporting Information [Line Items]
Selling, general and administrative expenses	1,653,000	1,240,000
Income (loss) from operations	(1,653,000)	(1,240,000)
Other income, net	6,000	1,000
INCOME BEFORE INCOME TAXES	(1,647,000)	(1,239,000)
Depreciation	3,000	2,000
Property, plant and equipment additions		50,000
Total assets	$ 61,093,000	$ 38,639,000

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Revenue earned during the period arising from products sold or services provided under the terms of a contract, not elsewhere specified in the taxonomy. May include government contracts, construction contracts, and any other contract related to a particular project or product.

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Total costs related to services rendered by an entity during the reporting period.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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This element represents the income or loss from continuing operations attributable to the economic entity which may also be defined as revenue less expenses from ongoing operations, after income or loss from equity method investments, but before income taxes, extraordinary items, and noncontrolling interest.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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The net result for the period of deducting operating expenses from operating revenues.

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The net amount of other income and expense amounts, the components of which are not separately disclosed on the income statement, resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business) also known as other nonoperating income (expense) recognized for the period. Such amounts may include: (a) dividends, (b) interest on securities, (c) net gains or losses on securities, (d) unusual costs, (e) gains or losses on foreign exchange transactions, and (f) miscellaneous other income and expense items.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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Amount of acquisition of long-lived, physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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