COSTS AND ESTIMATED EARNINGS ON UNCOMPLETED CONTRACTS (Details) - USD ($)	Jul. 31, 2017	Apr. 30, 2017
Costs incurred on uncompleted contracts	$ 17,191,287	$ 16,362,011
Estimated contract earnings	3,849,901	3,714,584
Gross Total	21,041,188	20,076,595
Less: Billings to date	23,618,114	21,771,566
Total	(2,576,926)	(1,694,971)
Costs and estimated earnings in excess of billings on uncompleted contracts	334,956	410,826
Billings in excess of cost and estimated earnings on uncompleted contracts	2,911,882	2,105,797
Total	$ (2,576,926)	$ (1,694,971)