INVESTMENT IN UNCONSOLIDATED JOINT VENTURES (Summarized Financial Information - 110 William Joint Venture) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Balance Sheet Related Disclosures [Abstract]
Real estate assets, net of accumulated depreciation and amortization	$ 818,841		$ 822,514
Total assets	1,267,496		1,004,214
Other liabilities	27,350		17,905
Total Liabilities and Equity	1,267,496		1,004,214
Balance outstanding	832,547
Deferred financing costs, net	12,758		3,523
Income Statement [Abstract]
Revenues	28,365	$ 27,943
Operating, maintenance, and management	9,520	8,944
Real estate taxes and insurance	3,874	3,659
Depreciation and amortization	11,008	11,229
Interest expense	5,176	3,911
Total expenses	33,106	30,658
Net (loss) income attributable to common stockholders	(4,894)	2,235
Company’s equity in loss of unconsolidated joint venture	(196)	(218)
Mortgages [Member] | Mezzanine Loan [Member]
Balance Sheet Related Disclosures [Abstract]
Balance outstanding			20,000
110 William Joint Venture [Member]
Balance Sheet Related Disclosures [Abstract]
Real estate assets, net of accumulated depreciation and amortization	268,618		269,664
Other assets	20,148		18,973
Total assets	288,766		288,637
Notes payable, net	161,210		162,395
Other liabilities	14,240		13,617
Partners’ capital	113,316		112,625
Total Liabilities and Equity	288,766		288,637
Income Statement [Abstract]
Revenues	8,251	8,285
Operating, maintenance, and management	2,505	2,703
Real estate taxes and insurance	1,434	1,336
Depreciation and amortization	3,121	3,060
Interest expense	1,516	1,533
Total expenses	8,576	8,632
Other income	16	1
Net (loss) income attributable to common stockholders	(309)	(346)
Company’s equity in loss of unconsolidated joint venture	(196)	$ (218)
110 William Joint Venture [Member] | Mortgages [Member] | First Mortgage Loan [Member]
Balance Sheet Related Disclosures [Abstract]
Balance outstanding	$ 138,000		138,600
Basis spread on variable rate	4.80%
110 William Joint Venture [Member] | Mortgages [Member] | Mezzanine Loan [Member]
Balance Sheet Related Disclosures [Abstract]
Balance outstanding	$ 20,000
Basis spread on variable rate	9.50%
110 William Joint Venture [Member] | Notes Payable [Member]
Balance Sheet Related Disclosures [Abstract]
Unamortized premium	$ 3,800		4,500
Deferred financing costs, net	$ 600		$ 700