CUSTOMER CONCENTRATIONS (Details) $ in Millions	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2020 USD ($) customer	Apr. 30, 2020 USD ($) Owner customer	Apr. 30, 2019 customer	Jan. 31, 2020 USD ($) Owner
Customer Concentrations
Number of project owners | Owner		3		3
Amounts retained by project owners	$ 20.0	$ 21.0		$ 20.0
Percentage of amounts retained by project owners		96.00%		82.00%
Accounts Receivable
Customer Concentrations
Number of customers | customer	3	1
Major Customer One
Customer Concentrations
Amounts retained by project owners	$ 6.5	$ 10.3		$ 6.5
Major Customer One | Accounts Receivable
Customer Concentrations
Percentage of consolidated accounts receivable accounted by major customer		33.00%		24.00%
Major Customer Two
Customer Concentrations
Amounts retained by project owners	5.9	$ 5.9		$ 5.9
Major Customer Two | Accounts Receivable
Customer Concentrations
Percentage of consolidated accounts receivable accounted by major customer				21.00%
Major Customer Three
Customer Concentrations
Amounts retained by project owners	$ 4.0	$ 4.0		$ 4.0
Major Customer Three | Accounts Receivable
Customer Concentrations
Percentage of consolidated accounts receivable accounted by major customer	12.00%
Power Services | Revenue
Customer Concentrations
Percentage of major customers or segments		81.00%	41.00%
Number of customers | customer		2	2
Power Services | Major Customer One | Revenue
Customer Concentrations
Percentage of major customers or segments		61.00%	17.00%
Power Services | Major Customer Two | Revenue
Customer Concentrations
Percentage of major customers or segments		17.00%	14.00%
Industry services | Revenue
Customer Concentrations
Percentage of major customers or segments		16.00%	55.00%