DISCONTINUED OPERATIONS, Reconciliation of Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Apr. 30, 2015
Carrying amounts of major classes of assets included as part of discontinued operations [Abstract]
Property owned and intangible assets, net of accumulated depreciation and amortization	$ 0	$ 417,045
Receivable arising from straight-lining of rents	0	10,078
Accounts receivable	0	566
Prepaid and other assets	0	699
Tax, insurance and other escrow	0	1,176
Goodwill	0	193
Deferred charges and leasing costs	0	9,606
Total major classes of assets of the discontinued operations	0	439,363
Other assets included in the disposal group classified as held for sale	22,064	23,740
Total assets of the disposal groups classified as held for sale on the balance sheet	22,064	463,103
Carrying amounts of major classes of liabilities included as part of discontinued operations [Abstract]
Accounts payable and accrued expenses	0	13,952
Mortgages payable	0	295,677
Other	0	4
Total major classes of liabilities of the discontinued operations	0	309,633
Other liabilities included in the disposal group classified as held for sale	11,449	11,760
Total liabilities of the disposal groups classified as held for sale on the balance sheet	$ 11,449	$ 321,393