SEGMENT DISCLOSURE - Operating Income (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) item	Mar. 31, 2015 USD ($)
Segment disclosure
Number of types of commercial real estate properties | item	3
Revenues	$ 66,390	$ 67,239
Property expenses:
General and administrative	1,763	2,592
EXPENSES	65,575	67,469
Reportable segments
Property expenses:
Total segment net operating income	34,413	34,093
Reportable segments | Office
Segment disclosure
Revenues	46,049	46,615
Property expenses:
Operating	18,487	19,391
General and administrative	354	313
EXPENSES	18,841	19,704
Total segment net operating income	27,208	26,911
Reportable segments | Hotel
Segment disclosure
Revenues	15,283	15,719
Property expenses:
Operating	9,955	10,677
General and administrative	87	41
EXPENSES	10,042	10,718
Total segment net operating income	5,241	5,001
Reportable segments | Multi-family
Segment disclosure
Revenues	5,058	4,905
Property expenses:
Operating	2,836	2,641
General and administrative	258	83
EXPENSES	3,094	2,724
Total segment net operating income	$ 1,964	$ 2,181