MORTGAGES PAYABLE AND CONSTRUCTION DEBT (Details) $ in Thousands	3 Months Ended
	Jul. 31, 2016 USD ($) loan	Apr. 30, 2016 USD ($)
Aggregate amount of required future principal payments on mortgages payable [Abstract]
Total payments	$ 812,082	$ 812,393
Mortgages Payable [Member]
Debt Instrument [Line Items]
Interest rates on mortgages payable range, minimum (in hundredths)	2.47%
Interest rates on mortgages payable range, maximum (in hundredths)	7.94%
Mortgages maturity date range, end	Jul. 01, 2036
Number of loans in default | loan	0
Fixed rate mortgages	$ 635,100	689,300
Variable rate mortgages	$ 249,200	$ 196,800
Weighted average interest rate (in hundredths)	4.54%	4.54%
Mortgage indebtness	$ 884,400
Aggregate amount of required future principal payments on mortgages payable [Abstract]
2017 (remainder)	79,673
2018	66,279
2019	145,153
2020	112,226
2021	154,461
Thereafter	258,834
Total payments	816,626
Mortgages Payable [Member] | Assets Held for Sale [Member]
Aggregate amount of required future principal payments on mortgages payable [Abstract]
2017 (remainder)	47,017
2018	1,106
2019	6,921
2020	612
2021	4,901
Thereafter	7,237
Total payments	$ 67,794