MORTGAGES PAYABLE AND LINE OF CREDIT (Details) $ in Thousands	3 Months Ended
	Jul. 31, 2015 USD ($) Property Loan	Apr. 30, 2015 USD ($)
Aggregate amount of required future principal payments on mortgages payable [Abstract]
Total payments	$ 669,734	$ 668,112
Mortgages Payable [Member]
Mortgages Payable [Abstract]
Interest rates on mortgages payable range, minimum (in hundredths)	2.69%
Interest rates on mortgages payable range, maximum (in hundredths)	8.25%
Mortgages maturity date	Jul. 01, 2036
Number of loans in default | Loan	1
Non-recourse loan	$ 122,600
Debt instrument maturity date	Oct. 06, 2015
Interest rate on mortgage payable (in hundredths)	5.93%
Fixed rate mortgages	$ 619,200	629,800
Variable rate mortgages	$ 50,600	$ 38,300
Weighted average rate of interest on mortgage debt (in hundredths)	4.89%	4.95%
Aggregate amount of required future principal payments on mortgages payable [Abstract]
2016 (remainder)	$ 65,336
2017	41,973
2018	39,278
2019	116,848
2020	72,598
Thereafter	333,701
Total payments	669,734
Mortgages Payable [Member] | Assets Held for Sale [Member]
Mortgages Payable [Abstract]
Minimum future principal payments		$ 293,000
Line of Credit [Member]
Line of Credit [Abstract]
Lending commitments	$ 100,000
Number of properties securing line of credit | Property	16
Line of credit, current interest rate (in hundredths)	4.75%
Line of credit, minimum outstanding principal balance	$ 17,500
Borrowed amount	$ 83,500	$ 60,500
Debt service coverage on aggregate assets	1.25
Debt service coverage on individual assets	1.00
Minimum depository accounts	$ 6,000
Non-interest bearing account	$ 1,500