SEGMENT REPORTING - Capital Expenditures (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 13,822	$ 15,486	$ 21,977	$ 33,238
Retail
Segment Reporting Information [Line Items]
Capital expenditures	[1]	2,800	4,250	4,046	9,664
Office
Segment Reporting Information [Line Items]
Capital expenditures	[1]	8,800	10,710	15,160	21,639
Multifamily
Segment Reporting Information [Line Items]
Capital expenditures	[1],[2]	2,109	475	2,568	1,819
Mixed-Use
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 113	$ 51	$ 203	$ 116

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

[2] d