MORTGAGES PAYABLE AND LINE OF CREDIT (Details) (USD $)	3 Months Ended
	Jul. 31, 2014 Property	Apr. 30, 2014
MORTGAGES PAYABLE AND LINE OF CREDIT [Abstract]
Interest rates on mortgages payable range, minimum (in hundredths)	2.40%
Interest rates on mortgages payable range, maximum (in hundredths)	8.25%
Mortgages maturity date range, end	Jul. 01, 2036
Fixed rate mortgages	$ 971,300,000	$ 977,200,000
Variable rate mortgages	45,400,000	20,500,000
Weighted average rate of interest on mortgage debt (in hundredths)	5.32%	5.37%
Aggregate amount of required future principal payments on mortgages payable [Abstract]
2015 (remainder)	70,760,000
2016	92,893,000
2017	214,722,000
2018	113,386,000
2019	132,793,000
Thereafter	393,020,000
Total payments	1,017,574,000	997,689,000
Long-term Debt, Percentage Bearing Fixed Interest, Amount	971,300,000	977,200,000
Lending commitments	75,000,000
Number of properties securing line of credit	14
Line of credit, current interest rate (in hundredths)	4.75%
Line of credit, minimum outstanding principal balance	12,500,000
Borrowed amount	35,500,000	25,500,000
Debt service coverage on aggregate assets	1.25
Debt service coverage on individual assets	1.00
Minimum depository accounts	6,000,000
Non-interest bearing account	$ 1,500,000