LINE OF CREDIT (Details) $ in Thousands		12 Months Ended
	Jan. 31, 2017 USD ($)	Apr. 30, 2017 USD ($) property	Apr. 30, 2016 USD ($)	Apr. 30, 2015 USD ($)	Jan. 30, 2017 USD ($)
Line of Credit Facility [Line Items]
Repayment of line of credit		$ 206,450	$ 125,000	$ 17,000
Line of Credit [Member] | First International Bank & Trust [Member]
Line of Credit Facility [Line Items]
Repayment of line of credit	$ 17,500
Credit Facility [Abstract]
Amount available					$ 100,000
Amount outstanding			$ 17,500
Line of Credit [Member] | BMO Line of Credit [Member]
Line of Credit Facility [Line Items]
Borrowing capacity with accordion option		250,000
Credit Facility [Abstract]
Amount available		206,000
Amount outstanding		$ 57,050
Interest rate (in hundredths)		2.74%
Maturity date	Jan. 31, 2021	Jan. 31, 2021
Weighted average interest rate (in hundredths)		2.67%
Line of Credit [Member] | Minimum [Member] | BMO Line of Credit [Member]
Line of Credit Facility [Line Items]
Properties in unencumbered asset pool | property		15
Line of Credit [Member] | Minimum [Member] | Base Rate [Member] | BMO Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate spread (as a percent)		0.60%
Line of Credit [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | BMO Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate spread (as a percent)		1.60%
Line of Credit [Member] | Maximum [Member] | BMO Line of Credit [Member]
Line of Credit Facility [Line Items]
Leverage ratio		0.60
Line of Credit [Member] | Maximum [Member] | Base Rate [Member] | BMO Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate spread (as a percent)		1.25%
Line of Credit [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | BMO Line of Credit [Member]
Line of Credit Facility [Line Items]
Interest rate spread (as a percent)	2.25%