CONDENSED CONSOLIDATED STATEMENTS OF EARNINGS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
REVENUES
Revenues	$ 175,444	$ 113,967	$ 468,287	$ 296,888
COST OF REVENUES
Cost of revenues	138,866	87,705	359,395	220,966
GROSS PROFIT	36,578	26,262	108,892	75,922
Impairment loss			1,979
Selling, general and administrative expenses	9,848	5,590	24,429	15,977
INCOME FROM OPERATIONS	26,730	20,672	82,484	59,945
Other income, net	690	732	1,283	944
INCOME BEFORE INCOME TAXES	27,420	21,404	83,767	60,889
Income tax expense	8,194	7,045	27,122	19,845
NET INCOME	19,226	14,359	56,645	41,044
Net income attributable to noncontrolling interests	1,153	3,552	6,668	11,427
NET INCOME ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC.	18,073	10,807	49,977	29,617
OTHER COMPREHENSIVE LOSS
Foreign currency translation adjustments, net of tax	(326)	(404)	(192)	(410)
COMPREHENSIVE INCOME ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC.	$ 17,747	$ 10,403	$ 49,785	$ 29,207
EARNINGS PER SHARE ATTRIBUTABLE TO THE STOCKHOLDERS OF ARGAN, INC.
Basic (in Dollars per share)	$ 1.19	$ 0.73	$ 3.34	$ 2.01
Diluted (in Dollars per share)	$ 1.16	$ 0.72	$ 3.23	$ 1.97
WEIGHTED AVERAGE NUMBER OF SHARES OUTSTANDING
Basic (in shares)	15,137	14,810	14,974	14,732
Diluted (in shares)	15,601	15,066	15,490	15,004
CASH DIVIDENDS PER SHARE (Note 14)	$ 1.00	$ 0.70	$ 1.00	$ 0.70
Power Industry Services
REVENUES
Revenues	$ 151,094	$ 111,592	$ 402,615	$ 287,947
COST OF REVENUES
Cost of revenues	118,407	86,103	302,140	214,618
GROSS PROFIT	32,687	25,489	100,475	73,329
Impairment loss			1,979
Selling, general and administrative expenses	6,391	3,240	13,688	9,671
INCOME FROM OPERATIONS	26,296	22,249	84,808	63,658
Other income, net	654	304	1,192	683
INCOME BEFORE INCOME TAXES	26,950	22,553	86,000	64,341
Industrial Fabrication And Field Services
REVENUES
Revenues	21,550		59,287
COST OF REVENUES
Cost of revenues	18,386		52,491
GROSS PROFIT	3,164		6,796
Selling, general and administrative expenses	1,410		4,532
INCOME FROM OPERATIONS	1,754		2,264
INCOME BEFORE INCOME TAXES	1,754		2,264
Telecommunications Infrastructure Services
REVENUES
Revenues	2,800	2,375	6,385	8,941
COST OF REVENUES
Cost of revenues	2,073	1,602	4,764	6,348
GROSS PROFIT	727	773	1,621	2,593
Selling, general and administrative expenses	316	303	944	1,022
INCOME FROM OPERATIONS	411	470	677	1,571
INCOME BEFORE INCOME TAXES	$ 411	$ 470	$ 677	$ 1,571