Segment Reporting Net Real Estate and Secured Note Payable Balances for Each Segment (Details) - USD ($) $ in Thousands		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	[1]	819,983	962,259
Capital Expenditures and Leasing Commissions	[2]	149,772	58,707
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.