UNAUDITED PRO FORMA FINANCIAL INFORMATION (Narrative) (Details) $ in Millions		3 Months Ended	9 Months Ended
	Jul. 11, 2016 property	Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($) property
Westpark Portfolio [Member] | Office Portfolio [Member]
Business Acquisition [Line Items]
Number of real estate properties acquired			1
353 Sacramento [Member] | Office Building [Member]
Business Acquisition [Line Items]
Number of real estate properties acquired	1		1
Westpark Portfolio and 353 Sacramento [Member]
Business Acquisition [Line Items]
Acquisition related costs | $		$ 2.0	$ 3.5