SEGMENT REPORTING - Capital Expenditures (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 22,437	$ 11,365
Retail
Segment Reporting Information [Line Items]
Capital expenditures	[1]	4,791	2,229
Office
Segment Reporting Information [Line Items]
Capital expenditures	[1]	16,483	7,373
Multifamily
Segment Reporting Information [Line Items]
Capital expenditures	[1]	771	1,609
Mixed-Use
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 392	$ 154

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