SEGMENT REPORTING - Operating Activity Within Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Segment Reporting Information [Line Items]
OPERATING INCOME	$ 23,504	$ 17,726	$ 46,748	$ 38,107
Total Segments' profit	43,578	40,570	86,945	81,904
Total Retail
Segment Reporting Information [Line Items]
Property revenue	24,376	23,570	48,414	46,569
Property expense	(6,258)	(6,448)	(12,258)	(12,506)
OPERATING INCOME	18,118	17,122	36,156	34,063
Total Office
Segment Reporting Information [Line Items]
Property revenue	24,036	22,447	47,613	45,305
Property expense	(6,988)	(6,085)	(13,809)	(12,978)
OPERATING INCOME	17,048	16,362	33,804	32,327
Total Multifamily
Segment Reporting Information [Line Items]
Property revenue	4,445	4,210	8,755	8,340
Property expense	(1,642)	(1,554)	(3,126)	(2,981)
OPERATING INCOME	2,803	2,656	5,629	5,359
Total Mixed-Use
Segment Reporting Information [Line Items]
Property revenue	13,912	11,972	28,022	25,965
Property expense	(8,303)	(7,542)	(16,666)	(15,810)
OPERATING INCOME	$ 5,609	$ 4,430	$ 11,356	$ 10,155