Segment Information - Segment Schedules (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) segment	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment	3
Real estate rental revenue	$ 77,501	$ 77,137
Real estate expenses	27,863	28,734
Gross Profit	49,638	48,403
Depreciation and amortization	(26,069)	(26,038)
Acquisition costs	0	(154)
General and administrative	(5,626)	(5,511)
Interest expense	(11,405)	(14,360)
Other income	77	39
Net income	6,615	2,379
Less: Net loss attributable to noncontrolling interests in subsidiaries	19	5
Net income attributable to the controlling interests	6,634	2,384
Capital expenditures	12,011	4,729
Total assets	2,254,109	2,185,303	$ 2,253,619
Office
Segment Reporting Information [Line Items]
Real estate rental revenue	38,027	43,818
Real estate expenses	14,414	17,075
Gross Profit	23,613	26,743
Capital expenditures	4,955	2,171
Total assets	1,097,256	1,254,906
Retail
Segment Reporting Information [Line Items]
Real estate rental revenue	15,705	15,380
Real estate expenses	3,863	4,406
Gross Profit	11,842	10,974
Capital expenditures	184	543
Total assets	348,221	351,616
Multifamily
Segment Reporting Information [Line Items]
Real estate rental revenue	23,769	17,939
Real estate expenses	9,586	7,253
Gross Profit	14,183	10,686
Capital expenditures	6,297	2,002
Total assets	764,732	524,856
Corporate and Other
Segment Reporting Information [Line Items]
Real estate rental revenue	0	0
Real estate expenses	0	0
Gross Profit	0	0
Capital expenditures	575	13
Total assets	$ 43,900	$ 53,925