BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES, Identified Intangible Assets and Liabilities (Details) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015	Apr. 30, 2016
Identified Intangible Assets and Liabilities and Goodwill [Abstract]
Finite-lived Intangible Assets Acquired			$ 0	$ 1,300,000
Addition to intangible liabilities			$ 0	$ 101,000
Weighted average lives of intangible assets acquired			0 years	29 days
Identified intangible assets (included in intangible assets) [Abstract]
Gross carrying amount	$ 6,103,000		$ 6,103,000		$ 8,088,000
Accumulated amortization	(5,261,000)		(5,261,000)		(6,230,000)
Net carrying amount	842,000		842,000		1,858,000
Identified intangible liabilities (included in other liabilities) [Abstract]
Gross carrying amount	157,000		157,000		159,000
Accumulated amortization	(65,000)		(65,000)		(55,000)
Net carrying amount	92,000		92,000		$ 104,000
Amortization of above and below market leases	4,000	$ 4,000	9,000	$ 11,000
Amortization of all other identified intangible assets	321,000	$ 331,000	995,000	$ 523,000
Estimated annual amortization of acquired below-market leases, net of acquired above-market leases [Abstract]
2018	(11,000)		(11,000)
2019	(20,000)		(20,000)
2020	(16,000)		(16,000)
2021	(13,000)		(13,000)
2022	(6,000)		(6,000)
Estimated annual amortization [Abstract]
2018	269,000		269,000
2019	170,000		170,000
2020	104,000		104,000
2021	78,000		78,000
2022	$ 25,000		$ 25,000