SEGMENT REPORTING - Operating Activity Within Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
OPERATING INCOME	$ 23,643	$ 23,244
Total Segments' profit	45,645	43,367
Total Retail
Segment Reporting Information [Line Items]
Property revenue	24,371	24,038
Property expense	(6,080)	(6,000)
OPERATING INCOME	18,291	18,038
Total Office
Segment Reporting Information [Line Items]
Property revenue	25,320	23,577
Property expense	(7,702)	(6,821)
OPERATING INCOME	17,618	16,756
Total Multifamily
Segment Reporting Information [Line Items]
Property revenue	6,294	4,310
Property expense	(2,820)	(1,484)
OPERATING INCOME	3,474	2,826
Total Mixed-Use
Segment Reporting Information [Line Items]
Property revenue	14,746	14,110
Property expense	(8,484)	(8,363)
OPERATING INCOME	$ 6,262	$ 5,747