COSTS, ESTIMATED EARNINGS AND BILLINGS ON UNCOMPLETED CONTRACTS (Details) - USD ($) $ in Thousands	Apr. 30, 2017	Jan. 31, 2017
COSTS, ESTIMATED EARNINGS AND BILLINGS ON UNCOMPLETED CONTRACTS
Costs charged to uncompleted contracts	$ 685,672	$ 485,629
Estimated accrued earnings	112,003	78,708
Contracts receivables, gross	797,675	564,337
Less - billings to date	1,027,662	770,386
Billings in excess of costs and estimated earnings on uncompleted contracts, net	(229,987)	(206,049)
Costs and estimated earnings in excess of billings	4,357	3,192
Billings in excess of costs and estimated earnings	234,344	$ 209,241
Retention payable	$ 25,700