REVENUES FROM CONTRACTS WITH CUSTOMERS - Accounting for the Loss Subcontract (Details) - TeesREPProject - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Jan. 31, 2021	Jan. 31, 2020	Mar. 24, 2020
REVENUES FROM CONTRACTS WITH CUSTOMERS
Loss recorded		$ 2.7		$ 33.6
Reversal of profit				$ 0.7
Excess of projected project costs over projected project revenues		$ 36.2
Percentage of completion of subcontracted work					90.00%
Subcontract loss	$ 29.5
The total amounts of accounts receivable and contract assets with the customer	$ 1.6		$ 4.7