SEGMENT REPORTING - Capital Expenditures (Details) ft² in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2016 USD ($) ft² unit	Mar. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 17,752	$ 44,968
Hassalo on Eighth - Residential [Member]
Segment Reporting Information [Line Items]
Number of units in real estate property | unit		657
Hassalo on Eighth - Retail [Member]
Segment Reporting Information [Line Items]
Net rentable area | ft²		47
Retail
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 5,414	935
Office
Segment Reporting Information [Line Items]
Capital expenditures	[1]	10,929	14,714
Multifamily
Segment Reporting Information [Line Items]
Capital expenditures	[1],[2]	1,344	28,948
Mixed-Use
Segment Reporting Information [Line Items]
Capital expenditures	[1]	$ 65	$ 371

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

[2] Multifamily capital expenditures include all capital expenditures incurred for the new development project Hassalo on Eighth, which consists of 657 multifamily units and approximately 47,000 square feet of retail space.