Commitments and Contingencies (Details) (USD $)	12 Months Ended			1 Months Ended			12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Maximum [Member] Santana Row [Member]	Mar. 31, 2011 Breach Of Contract [Member]	Jun. 30, 2009 Breach Of Contract [Member]	Dec. 31, 2009 Breach Of Contract [Member]	Dec. 31, 2010 Insurance Settlement [Member]	Dec. 31, 2012 Capital Improvement, Development, And Redevelopment Projects [Member]	Sep. 30, 2023 Mercer Mall [Member] Purchased Call Option [Member]	Sep. 30, 2025 Mercer Mall [Member] Put Option [Member]	Dec. 31, 2012 Congressional Plaza [Member] Put Option [Member]	Dec. 31, 2012 Congressional Plaza [Member] Put Option [Member] Minimum [Member]	Dec. 31, 2012 Congressional Plaza [Member] Put Option [Member] Maximum [Member]	Dec. 31, 2012 Project In Southern California [Member] Put Option [Member]	Dec. 30, 2013 Plaza El Segundo [Member] Put Option [Member]	Dec. 30, 2013 Obligation To Purchase Member One Ownership Interest [Member] Plaza El Segundo [Member] Put Option [Member]	Dec. 30, 2013 Obligation To Purchase Member Two Ownership Interest [Member] Plaza El Segundo [Member] Put Option [Member]	Jan. 01, 2017 Option To Purchase Preferred Interest [Member] Plaza El Segundo [Member] Maximum [Member]	Dec. 31, 2012 Obligation To Purchase Member Three Ownership Interest [Member] Montrose Crossing [Member] Put Option [Member]	Oct. 16, 2021 Melville Mall [Member] Purchased Call Option [Member]	Oct. 16, 2023 Melville Mall [Member] Put Option [Member]	Dec. 31, 2012 Melville Mall [Member]	Dec. 31, 2011 Melville Mall [Member]
Loss Contingencies [Line Items]
Loss Contingency, Court Decision, Amount					$ 15,900,000
Loss Contingency, Estimate of Possible Loss						16,400,000
Final judgment related to a previously disclosed lawsuit				16,200,000			1,000,000
Warranty Period			10 years
Product Warranty Accrual	7,100,000	7,100,000
Product Warranty Accrual, Payments	1,300,000	900,000
Letters of Credit Outstanding, Amount	15,900,000
Contractual Obligation								233,000,000
Purchase Price Under Option									55,000,000	60,000,000								4,900,000		5,000,000	5,000,000
Mortgage loan face amount																						21,536,000	22,325,000
Option Indexed to Issuer's Equity, Percentage Of Indexed Ownership Interest											100.00%
Option Indexed to Issuer's Equity, Indexed Owenship Interest											29.47%			10.00%		10.00%	11.80%		10.10%
Estimated Maximum Liability Upon Exercise Of Option												65,000,000	71,000,000
Number of Members With Purchase Options															2
Operating partnership units, outstanding	320,646
Operating partnership units outstanding, fair value	33,400,000
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2013	1,488,000
2014	1,478,000
2015	1,428,000
2016	1,372,000
2017	1,088,000
Thereafter	50,207,000
Total	$ 57,061,000