FAIR VALUE OF FINANCIAL INSTRUMENTS (Details) - USD ($) $ in Thousands		Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Financial Assets [Abstract]
Cash and Cash Equivalents, at Carrying Value		$ 10	$ 522	$ 33	$ 48
Fair Value [Member]
Financial Assets [Abstract]
Cash and Cash Equivalents, Fair Value Disclosure		10	522
Mortgage loans receivable		4,657	4,747
Interest rate swap assets		4,183	4,546
Financial Liabilities [Abstract]
Unsecured bank credit facilities - variable rate	[1]	137,380	111,923
Unsecured bank credit facilities - fixed rate	[1]	80,002	79,998
Unsecured debt Fair Value Disclosure	[1]	644,834	623,147
Secured debt	[1]	210,880	266,585
Interest rate swap liabilities		1,552	2,578
Carrying Amount [Member]
Financial Assets [Abstract]
Cash and Cash Equivalents, at Carrying Value	[2]	10	522
Mortgage loans receivable	[2]	4,656	4,752
Interest rate swap assets	[2]	4,183	4,546
Financial Liabilities [Abstract]
Unsecured bank credit facilities - variable rate	[1],[2]	137,374	112,020
Unsecured bank credit facilities - fixed rate	[1],[2]	80,000	80,000
Unsecured debt Fair Value Disclosure	[1],[2]	655,000	655,000
Secured debt	[1],[2]	203,093	258,594
Interest rate swap liabilities	[2]	$ 1,552	$ 2,578

[1] Carrying amounts and fair values shown in the table exclude debt issuance costs (see Note 9 for additional information).

[2] Carrying amounts shown in the table are included on the Consolidated Balance Sheets under the indicated captions, except as explained in the notes below.(2) Carrying amounts and fair values shown in the table exclude debt issuance costs (see Note 9 for additional information).The following methods and assumptions were used to estimate the fair value of each class of financial instruments:Cash and cash equivalents: The carrying amounts approximate fair value due to the short maturity of those instruments.Mortgage loans receivable (included in Other assets on the Consolidated Balance Sheets): The fair value is estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities (Level 2 input).Interest rate swap assets (included in Other assets on the Consolidated Balance Sheets): The instruments are recorded at fair value based on models using inputs, such as interest rate yield curves, LIBOR swap curves and OIS curves, observable for substantially the full term of the contract (Level 2 input). See Note 13 for additional information on the Company's interest rate swaps.Unsecured bank credit facilities: The fair value of the Company’s unsecured bank credit facilities is estimated by discounting expected cash flows at current market rates (Level 2 input), excluding the effects of debt issuance costs.Unsecured debt: The fair value of the Company’s unsecured debt is estimated by discounting expected cash flows at the rates currently offered to the Company for debt of the same remaining maturities, as advised by the Company’s bankers (Level 2 input), excluding the effects of debt issuance costs.Secured debt: The fair value of the Company’s secured debt is estimated by discounting expected cash flows at the rates currently offered to the Company for debt of the same remaining maturities, as advised by the Company’s bankers (Level 2 input), excluding the effects of debt issuance costs.Interest rate swap liabilities (included in Other liabilities on the Consolidated Balance Sheets): The instruments are recorded at fair value based on models using inputs, such as interest rate yield curves, LIBOR swap curves and OIS curves, observable for substantially the full term of the contract (Level 2 input). See Note 13 for additional information on the Company's interest rate swaps.