MORTGAGES PAYABLE AND CONSTRUCTION DEBT (Details) $ in Thousands	9 Months Ended
	Jan. 31, 2017 USD ($) loan	Apr. 30, 2016 USD ($)
Aggregate amount of required future principal payments on mortgages payable [Abstract]
Total payments	$ 688,424	$ 812,393
Mortgages Payable [Member]
Debt Instrument [Line Items]
Interest rates on mortgages payable range, minimum (in hundredths)	3.02%
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	$ 658,200	689,300
Variable rate mortgages	$ 81,300	$ 196,800
Weighted average interest rate (in hundredths)	4.74%	4.54%
Mortgage indebtness	$ 739,500
Aggregate amount of required future principal payments on mortgages payable [Abstract]
2017 (remainder)	11,847
2018	47,510
2019	79,107
2020	95,092
2021	137,880
Thereafter	322,513
Total payments	693,949
Mortgages Payable [Member] | Assets Held for Sale [Member]
Aggregate amount of required future principal payments on mortgages payable [Abstract]
2017 (remainder)	30,477
2018	819
2019	2,326
2020	668
2021	711
Thereafter	10,588
Total payments	$ 45,589