CERTAIN RELATIONSHIPS AND RELATED PARTY TRANSACTIONS (Relationships with RRE Opportunity REIT, Atlas Energy, L.P. and 1845 Walnut Associates Ltd.) (Details) $ in Thousands	1 Months Ended		12 Months Ended
	Dec. 31, 2013 USD ($)	Oct. 31, 2012 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	May. 31, 2013 ft²
Related Party Transaction [Line Items]
Issuance of common shares				$ 41	$ 104
Loans and receivables from managed entities and related parties, net			$ 26,667	$ 32,745
RRE Opportunity REIT [Member]
Related Party Transaction [Line Items]
Issuance of common shares	$ 635,000
Loans and receivables from managed entities and related parties, net			277
Atlas Energy, L.P. [Member]
Related Party Transaction [Line Items]
Loans and receivables from managed entities and related parties, net			$ 12
1845 Walnut Associates Ltd. [Member]
Related Party Transaction [Line Items]
Equity interest, ownership percentage			7.00%
Lease term			10 years
Area of real estate property | ft²						34,476
Payments for tenant improvements		$ 1,500
Potential extended additional term		5 years