Segment Reporting Net Real Estate and Secured Note Payable Balances for Each Segment (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013
Segment Reporting Information [Line Items]
Net Real Estate	$ 1,775,400		$ 1,676,836
Secured Notes Payable	819,983	[1]	962,259	[1]
Capital Expenditures and Leasing Commissions	149,772	[2]	58,707	[2]
Total Retail
Segment Reporting Information [Line Items]
Net Real Estate	639,456		651,707
Secured Notes Payable	161,975		303,249
Capital Expenditures and Leasing Commissions	8,671		4,849
Total Office
Segment Reporting Information [Line Items]
Net Real Estate	757,854		750,890
Secured Notes Payable	426,254		427,256
Capital Expenditures and Leasing Commissions	34,577		27,275
Total Multifamily
Segment Reporting Information [Line Items]
Net Real Estate	182,468		74,612
Secured Notes Payable	101,444		101,444
Capital Expenditures and Leasing Commissions	101,392		24,641
Total Mixed-Use
Segment Reporting Information [Line Items]
Net Real Estate	195,622		199,627
Secured Notes Payable	130,310		130,310
Capital Expenditures and Leasing Commissions	$ 5,132		$ 1,942

[1] Excludes unamortized fair market value adjustment of $7.2 million and $10.1 million as of December 31, 2014 and 2013, respectively.

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