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Major Customers - Additional Information (Detail) (Power Industry Services [Member]) | 3 Months Ended | 9 Months Ended
--- | --- | ---
Oct. 31, 2013 Customer | Oct. 31, 2012 Customer | Oct. 31, 2013 Customer | Oct. 31, 2012 Customer
Revenue, Major Customer [Line Items] |  |  |  |
Percentage of consolidated net revenue accounted by major segment | 96.00% | 95.00% | 95.00% | 93.00%
Number of major power industry service customers | 2 | 3 | 3 | 2
Major Customer One [Member] |  |  |  |
Revenue, Major Customer [Line Items] |  |  |  |
Percentage of consolidated net revenue accounted by major customers | 49.00% | 60.00% | 36.00% | 57.00%
Major Customer Two [Member] |  |  |  |
Revenue, Major Customer [Line Items] |  |  |  |
Percentage of consolidated net revenue accounted by major customers | 28.00% | 23.00% | 30.00% | 15.00%
Major Customer Three [Member] |  |  |  |
Revenue, Major Customer [Line Items] |  |  |  |
Percentage of consolidated net revenue accounted by major customers |  | 10.00% | 20.00% |

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