SEGMENT REPORTING (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jul. 31, 2012	Jul. 31, 2011	Apr. 30, 2012	Apr. 30, 2011
SEGMENT REPORTING [Abstract]
Number of reportable segments	5
Segment revenues and net operating income [Abstract]
Real estate revenue	$ 62,410	$ 59,557
Real estate expenses	25,068	24,859
Net operating income	37,342	34,698
Depreciation/amortization	(16,286)	(14,873)
Administrative, advisory and trustee services	(2,096)	(2,181)
Other expenses	(519)	(315)
Interest expense	(16,517)	(15,881)
Interest and other income	142	153
Income from continuing operations	2,066	1,601
Income from discontinued operations	(70)	(28)
Net Income	1,996	1,573
Segment Assets [Abstract]
Property owned	1,979,099		1,892,009
Less accumulated depreciation	(387,286)		(373,490)
Total property owned	1,591,813		1,518,519
Real Estate Held-for-sale	1,131		2,067
Cash and cash equivalents	37,002	37,307	39,989	41,191
Other investments	635		634
Receivables and other assets	114,990		114,569
Development in progress	10,498		27,599
Unimproved land	10,990		10,990
Total Assets	1,767,059		1,714,367
Multi-Family Residential [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	21,635	17,482
Real estate expenses	9,522	8,366
Net operating income	12,113	9,116
Segment Assets [Abstract]
Property owned	622,873		539,783
Less accumulated depreciation	(133,127)		(128,834)
Total property owned	489,746		410,949
Commercial-Office [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	18,638	18,815
Real estate expenses	9,289	8,944
Net operating income	9,349	9,871
Segment Assets [Abstract]
Property owned	607,182		605,318
Less accumulated depreciation	(125,743)		(121,422)
Total property owned	481,439		483,896
Commercial-Medical [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	15,327	16,617
Real estate expenses	4,082	5,520
Net operating income	11,245	11,097
Segment Assets [Abstract]
Property owned	501,649		500,268
Less accumulated depreciation	(82,310)		(78,744)
Total property owned	419,339		421,524
Commercial-Industrial [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	3,459	3,435
Real estate expenses	1,019	966
Net operating income	2,440	2,469
Segment Assets [Abstract]
Property owned	119,287		119,002
Less accumulated depreciation	(21,448)		(20,693)
Total property owned	97,839		98,309
Commercial-Retail [Member]
Segment revenues and net operating income [Abstract]
Real estate revenue	3,351	3,208
Real estate expenses	1,156	1,063
Net operating income	2,195	2,145
Segment Assets [Abstract]
Property owned	128,108		127,638
Less accumulated depreciation	(24,658)		(23,797)
Total property owned	$ 103,450		$ 103,841