SEGMENT REPORTING - Operating Activity Within Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
OPERATING INCOME	$ 24,487	$ 17,249	$ 53,308	$ 30,169
Total Segments' profit	53,012	55,513	108,489	107,279
Total Retail
Segment Reporting Information [Line Items]
Property revenue	25,871	26,415	55,308	52,572
Property expense	(7,731)	(7,138)	(14,885)	(13,949)
OPERATING INCOME	18,140	19,277	40,423	38,623
Total Office
Segment Reporting Information [Line Items]
Property revenue	30,200	31,052	58,006	57,822
Property expense	(9,269)	(8,342)	(17,758)	(16,355)
OPERATING INCOME	20,931	22,710	40,248	41,467
Total Multifamily
Segment Reporting Information [Line Items]
Property revenue	12,897	12,622	25,796	25,046
Property expense	(4,883)	(5,020)	(9,956)	(10,017)
OPERATING INCOME	8,014	7,602	15,840	15,029
Total Mixed-Use
Segment Reporting Information [Line Items]
Property revenue	15,145	14,934	30,322	30,315
Property expense	(9,218)	(9,010)	(18,344)	(18,155)
OPERATING INCOME	$ 5,927	$ 5,924	$ 11,978	$ 12,160