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DESCRIPTION OF THE BUSINESS AND BASIS OF PRESENTATION (Details) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Jan. 31, 2018 USD ($) | Oct. 31, 2017 USD ($) | Jul. 31, 2017 USD ($) | Apr. 30, 2017 USD ($) | Jan. 31, 2017 USD ($) | Oct. 31, 2016 USD ($) | Jul. 31, 2016 USD ($) | Apr. 30, 2016 USD ($) | Jan. 31, 2018 USD ($) category | Jan. 31, 2017 USD ($) | Jan. 31, 2016 USD ($)
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Revenues | $ 169,578 | $ 232,945 | $ 259,803 | $ 230,489 | $ 206,760 | $ 175,444 | $ 162,495 | $ 130,348 | $ 892,815 | $ 675,047 | $ 413,275
Minimum |  |  |  |  |  |  |  |  |  |  |
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Estimated useful lives of the assets |  |  |  |  |  |  |  |  | 5 years |  |
Maximum |  |  |  |  |  |  |  |  |  |  |
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Estimated useful lives of the assets |  |  |  |  |  |  |  |  | 39 years |  |
Power Services |  |  |  |  |  |  |  |  |  |  |
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Unapproved change orders contract amount | $ 9,300 |  |  |  | $ 2,700 |  |  |  | $ 9,300 | 2,700 |
Number of categories | category |  |  |  |  |  |  |  |  | 2 |  |
Revenues |  |  |  |  |  |  |  |  | $ 814,544 | $ 586,628 | $ 387,636
Power Services | Minimum |  |  |  |  |  |  |  |  |  |  |
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Revenue recognition period |  |  |  |  |  |  |  |  | 3 months |  |
Power Services | Maximum |  |  |  |  |  |  |  |  |  |  |
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Revenue recognition period |  |  |  |  |  |  |  |  | 3 years |  |
GPS |  |  |  |  |  |  |  |  |  |  |
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Consolidated revenues by subsidiaries |  |  |  |  |  |  |  |  | 88.00% | 85.00% | 90.00%
Core services | Power Services |  |  |  |  |  |  |  |  |  |  |
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  | $ 814,544 | $ 586,628 | $ 383,378
Project development success fees | Power Services |  |  |  |  |  |  |  |  |  |  |
Description of the Business |  |  |  |  |  |  |  |  |  |  |
Revenues |  |  |  |  |  |  |  |  |  |  | $ 4,258

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