SEGMENT REPORTING (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013	Apr. 30, 2013	Apr. 30, 2012
Segment revenues and net operating income [Abstract]
Real estate revenue	$ 67,629	$ 63,080	$ 198,499	$ 183,874
Real estate expenses	25,927	25,348	78,898	73,102
Gain on involuntary conversion	1,514	0	2,480	2,263
Net operating income	43,216	37,732	122,081	113,035
Depreciation/amortization	(17,489)	(15,493)	(53,656)	(46,505)
Administrative, advisory and trustee services	(2,662)	(2,245)	(7,942)	(6,402)
Impairment of real estate investments	(4,798)		(4,798)
Other expenses	(273)	(464)	(1,630)	(1,496)
Interest expense	(15,130)	(15,197)	(44,525)	(46,554)
Interest and other income	740	255	1,602	600
Income from continuing operations	3,604	4,588	11,132	12,678
Income from discontinued operations	465	1,565	6,450	5,481
Net income	4,069	6,153	17,582	18,159
Segment Assets [Abstract]
Property owned	2,042,290		2,042,290		2,032,970
Less accumulated depreciation	(439,233)		(439,233)		(420,421)
Net property owned	1,603,057		1,603,057		1,612,549
Cash and cash equivalents	53,494	62,302	53,494	62,302	94,133	39,989
Other investments	643		643		639
Receivables and other assets	136,780		136,780		113,948
Development in progress	89,086		89,086		46,782
Unimproved land	21,498		21,498		21,503
Total Assets	1,904,558		1,904,558		1,889,554
Multi-Family Residential [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	25,848	22,859	75,659	66,758
Real estate expenses	10,998	10,208	33,006	28,284
Gain on involuntary conversion	1,514		2,480	2,263
Net operating income	16,364	12,651	45,133	40,737
Segment Assets [Abstract]
Property owned	738,948		738,948		659,696
Less accumulated depreciation	(152,447)		(152,447)		(140,354)
Net property owned	586,501		586,501		519,342
Commercial-Office [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	19,394	19,046	58,075	56,214
Real estate expenses	9,037	9,270	28,315	27,591
Gain on involuntary conversion	0		0	0
Net operating income	10,357	9,776	29,760	28,623
Segment Assets [Abstract]
Property owned	613,663		613,663		613,775
Less accumulated depreciation	(147,392)		(147,392)		(138,270)
Net property owned	466,271		466,271		475,505
Commercial-Healthcare [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	17,242	15,952	49,340	46,286
Real estate expenses	4,120	4,128	12,534	12,387
Gain on involuntary conversion	0		0	0
Net operating income	13,122	11,824	36,806	33,899
Segment Assets [Abstract]
Property owned	517,441		517,441		501,191
Less accumulated depreciation	(102,027)		(102,027)		(90,891)
Net property owned	415,414		415,414		410,300
Commercial-Industrial [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	1,664	1,738	5,273	4,704
Real estate expenses	493	492	1,447	1,350
Gain on involuntary conversion	0		0	0
Net operating income	1,171	1,246	3,826	3,354
Segment Assets [Abstract]
Property owned	55,268		55,268		125,772
Less accumulated depreciation	(9,848)		(9,848)		(23,688)
Net property owned	45,420		45,420		102,084
Commercial-Retail [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	3,481	3,485	10,152	9,912
Real estate expenses	1,279	1,250	3,596	3,490
Gain on involuntary conversion	0		0	0
Net operating income	2,202	2,235	6,556	6,422
Segment Assets [Abstract]
Property owned	116,970		116,970		132,536
Less accumulated depreciation	(27,519)		(27,519)		(27,218)
Net property owned	$ 89,451		$ 89,451		$ 105,318