REVENUES FROM CONTRACT WITH CUSTOMERS - Accounting for the Loss Subcontract (Details) - USD ($) $ in Millions	3 Months Ended			6 Months Ended	12 Months Ended
	Jul. 31, 2020	Jul. 31, 2019	Apr. 30, 2019	Jul. 31, 2020	Jan. 31, 2020	Mar. 24, 2020
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Provision for contract loss				$ 2.3	$ 5.8
TeesREPProject
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Loss recorded			$ 27.6
Reversal of profit			$ 0.7
Increase in Cost for Project Over Projected Revenues		$ 3.4
Excess of projected project costs over projected project revenues	$ 32.3
Percentage of completion of subcontracted work						90.00%
Reduction to the subcontract loss	(4.2)
Adjustments in the amount made to the APC	$ 1.9
The total amounts of accounts receivable and contract assets with the customer				$ 11.2	$ 19.2