Segment Reporting - Summarized Operating Results and Certain Financial Position Data of Company's Reportable Continuing Business Segments (Detail) (USD $)	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012	Jan. 31, 2013
Segment Reporting Information [Line Items]
Net revenues	$ 63,452,000	$ 74,486,000	$ 167,964,000	$ 220,794,000
Cost of revenues	39,576,000	61,350,000	109,803,000	184,678,000
Gross profit	23,876,000	13,136,000	58,161,000	36,116,000
Selling, general and administrative expenses	3,545,000	3,780,000	8,589,000	10,105,000
Income (loss) from operations	20,331,000	9,356,000	49,572,000	26,011,000
Gains on the deconsolidation of VIEs			2,444,000
Other income (expense), net	261,000	(11,000)	827,000	(29,000)
Income (loss) from continuing operations before income taxes	20,592,000	9,345,000	52,843,000	25,982,000
Income tax expense	8,143,000	3,632,000	19,531,000	9,741,000
Income from continuing operations	12,449,000	5,713,000	33,312,000	16,241,000
Amortization of purchased intangibles	61,000	61,000	182,000	182,000
Depreciation	142,000	136,000	407,000	385,000
Property, plant and equipment additions	84,000	2,139,000	925,000	5,928,000
Goodwill	18,476,000	18,476,000	18,476,000	18,476,000	18,476,000
Total assets	260,448,000	254,985,000	260,448,000	254,985,000	234,724,000
Power Industry Services [Member]
Segment Reporting Information [Line Items]
Net revenues	61,103,000	70,527,000	160,392,000	206,364,000
Cost of revenues	38,012,000	58,173,000	104,062,000	173,339,000
Telecommunications Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Net revenues	2,349,000	3,959,000	7,572,000	14,430,000
Cost of revenues	1,564,000	3,177,000	5,741,000	11,339,000
Operating Segments [Member] | Power Industry Services [Member]
Segment Reporting Information [Line Items]
Net revenues	61,103,000	70,527,000	160,392,000	206,364,000
Cost of revenues	38,012,000	58,173,000	104,062,000	173,339,000
Gross profit	23,091,000	12,354,000	56,330,000	33,025,000
Selling, general and administrative expenses	1,814,000	2,042,000	5,254,000	5,533,000
Income (loss) from operations	21,277,000	10,312,000	51,076,000	27,492,000
Gains on the deconsolidation of VIEs			2,444,000
Other income (expense), net	260,000	(12,000)	825,000	(31,000)
Income (loss) from continuing operations before income taxes	21,537,000	10,300,000	54,345,000	27,461,000
Amortization of purchased intangibles	61,000	61,000	182,000	182,000
Depreciation	96,000	77,000	268,000	205,000
Property, plant and equipment additions	69,000	2,092,000	880,000	5,707,000
Goodwill	18,476,000	18,476,000	18,476,000	18,476,000
Total assets	216,492,000	198,531,000	216,492,000	198,531,000
Operating Segments [Member] | Telecommunications Infrastructure Services [Member]
Segment Reporting Information [Line Items]
Net revenues	2,349,000	3,959,000	7,572,000	14,430,000
Cost of revenues	1,564,000	3,177,000	5,741,000	11,339,000
Gross profit	785,000	782,000	1,831,000	3,091,000
Selling, general and administrative expenses	344,000	452,000	991,000	1,333,000
Income (loss) from operations	441,000	330,000	840,000	1,758,000
Income (loss) from continuing operations before income taxes	441,000	330,000	840,000	1,758,000
Depreciation	45,000	58,000	137,000	178,000
Property, plant and equipment additions	15,000	47,000	62,000	221,000
Total assets	2,381,000	3,995,000	2,381,000	3,995,000
Other [Member]
Segment Reporting Information [Line Items]
Selling, general and administrative expenses	1,387,000	1,286,000	2,344,000	3,239,000
Income (loss) from operations	(1,387,000)	(1,286,000)	(2,344,000)	(3,239,000)
Other income (expense), net	1,000	1,000	2,000	2,000
Income (loss) from continuing operations before income taxes	(1,386,000)	(1,285,000)	(2,342,000)	(3,237,000)
Depreciation	1,000	1,000	2,000	2,000
Total assets	$ 41,575,000	$ 52,459,000	$ 41,575,000	$ 52,459,000