SEGMENT REPORTING - Capital Expenditures (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 11,365	$ 8,155
Retail
Segment Reporting Information [Line Items]
Capital expenditures	[1]	2,229	1,246
Office
Segment Reporting Information [Line Items]
Capital expenditures	[1]	7,373	6,360
Multifamily
Segment Reporting Information [Line Items]
Capital expenditures	[1]	1,609	459
Mixed-Use
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 154	$ 90

[1] Capital expenditures represent cash paid for capital expenditures during the period and include leasing commissions paid