RELATED PARTY TRANSACTIONS (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)	May 29, 2015 USD ($) ft² $ / ft²
Related Party Transaction [Line Items]
Due from related party	$ 223		$ 0
KBS Capital Advisors LLC [Member] | Property Insurance Rebate [Member]
Related Party Transaction [Line Items]
Due from related party	200	$ 200
KBS Capital Advisors LLC [Member] | Legal and Professional Fees [Member]
Related Party Transaction [Line Items]
Due from related party		100
Affiliated Entity [Member] | Subsidiaries [Member]
Related Party Transaction [Line Items]
Net rentable area | ft²				5,046
Percent of total rentable square feet				2.30%
Annualized base rent				$ 200
Average annualized base rent per square foot | $ / ft²				46.38
Rental income	$ 100	$ 100