SEGMENT REPORTING (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2019 USD ($)	Oct. 31, 2018 USD ($)	Jul. 31, 2018 USD ($)	Apr. 30, 2018 USD ($)	Jan. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Jul. 31, 2017 USD ($)	Apr. 30, 2017 USD ($)	Jan. 31, 2019 USD ($) item	Jan. 31, 2018 USD ($)	Jan. 31, 2017 USD ($)
Segment Reporting Information
Operating segment | item									1
Revenues	$ 87,658	$ 116,459	$ 136,670	$ 141,366	$ 169,578	$ 232,945	$ 259,803	$ 230,489	$ 482,153	$ 892,815	$ 675,047
Cost of revenues									399,715	743,490	528,336
Gross profit	6,746	29,532	30,708	15,452	20,104	37,718	51,407	40,096	82,438	149,325	146,711
Selling, general and administrative expenses									40,710	41,764	32,478
Impairment loss									1,491	584	1,979
Income (loss) from operations	(4,293)	$ 18,385	$ 20,330	$ 5,815	8,163	$ 27,599	$ 40,608	$ 30,607	40,237	106,977	112,254
Other income, net									6,981	5,648	2,278
Income (loss) before income taxes									47,218	112,625	114,532
Income tax benefit (expense)									4,651	(40,279)	(37,106)
Net income									51,869	72,346	77,426
Amortization of purchased intangible assets									1,012	1,032	1,163
Depreciation									3,422	2,779	2,043
Property, plant and equipment additions									8,599	4,826	2,811
Current assets	416,348				485,027				416,348	485,027
Current liabilities	82,276				183,262				82,276	183,262
Goodwill	32,838				34,329				32,838	34,329	34,913
Total assets	476,648				542,669				476,648	542,669	644,488
Power Services
Segment Reporting Information
Revenues									367,812	814,544	586,628
Cost of revenues									297,931	675,362	452,599
Gross profit									69,881	139,182	134,029
Selling, general and administrative expenses									23,741	23,356	17,588
Impairment loss											1,979
Income (loss) from operations									46,140	115,826	114,462
Other income, net									5,120	5,391	2,145
Income (loss) before income taxes									51,260	121,217	116,607
Amortization of purchased intangible assets									350	350	350
Depreciation									749	885	665
Property, plant and equipment additions									3,156	1,362	1,005
Current assets	317,708								317,708
Current liabilities	67,045								67,045
Goodwill	20,548				20,548				20,548	20,548	20,548
Total assets	347,189				432,932				347,189	432,932	488,431
Industrial Services
Segment Reporting Information
Revenues									101,673	65,303	78,994
Cost of revenues									92,097	58,283	68,354
Gross profit									9,576	7,020	10,640
Selling, general and administrative expenses									7,904	7,401	6,264
Impairment loss									1,491	584
Income (loss) from operations									181	(965)	4,376
Other income, net									1,400
Income (loss) before income taxes									1,581	(965)	4,376
Amortization of purchased intangible assets									662	682	813
Depreciation									2,293	1,607	1,165
Property, plant and equipment additions									4,750	2,837	1,238
Current assets	28,878								28,878
Current liabilities	13,384								13,384
Goodwill	12,290				13,781				12,290	13,781	14,365
Total assets	57,168				44,849				57,168	44,849	47,316
Telecom Services
Segment Reporting Information
Revenues									12,668	12,968	9,425
Cost of revenues									9,687	9,845	7,383
Gross profit									2,981	3,123	2,042
Selling, general and administrative expenses									1,788	1,395	1,430
Income (loss) from operations									1,193	1,728	612
Income (loss) before income taxes									1,193	1,728	612
Depreciation									366	274	201
Property, plant and equipment additions									690	625	563
Current assets	3,691								3,691
Current liabilities	879								879
Total assets	5,272				4,873				5,272	4,873	4,318
Other
Segment Reporting Information
Selling, general and administrative expenses									7,277	9,612	7,196
Income (loss) from operations									(7,277)	(9,612)	(7,196)
Other income, net									461	257	133
Income (loss) before income taxes									(6,816)	(9,355)	(7,063)
Depreciation									14	13	12
Property, plant and equipment additions									3	2	5
Current assets	66,071								66,071
Current liabilities	968								968
Total assets	$ 67,019				$ 60,015				67,019	60,015	104,423
Intercompany Eliminations
Segment Reporting Information
Revenues									$ 800	$ 2,200	$ 1,000