SEGMENT REPORTING - Operating Activity Within Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
OPERATING INCOME	$ 17,249	$ 20,048	$ 30,169	$ 43,377
Total Segments' profit	55,513	49,361	107,279	95,758
Total Retail
Segment Reporting Information [Line Items]
Property revenue	26,415	24,954	52,572	49,745
Property expense	(7,138)	(6,794)	(13,949)	(13,485)
OPERATING INCOME	19,277	18,160	38,623	36,260
Total Office
Segment Reporting Information [Line Items]
Property revenue	31,052	26,359	57,822	52,349
Property expense	(8,342)	(8,045)	(16,355)	(15,846)
OPERATING INCOME	22,710	18,314	41,467	36,503
Total Multifamily
Segment Reporting Information [Line Items]
Property revenue	12,622	11,023	25,046	18,914
Property expense	(5,020)	(4,082)	(10,017)	(7,293)
OPERATING INCOME	7,602	6,941	15,029	11,621
Total Mixed-Use
Segment Reporting Information [Line Items]
Property revenue	14,934	14,770	30,315	29,890
Property expense	(9,010)	(8,824)	(18,155)	(18,516)
OPERATING INCOME	$ 5,924	$ 5,946	$ 12,160	$ 11,374