Commitments and Contingencies (Details) (USD $)	12 Months Ended				1 Months Ended	3 Months Ended				12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 Santana Row [Member]	Dec. 31, 2011 Maximum [Member]	Mar. 31, 2011 Breach Of Contract [Member]	Mar. 31, 2009 Breach Of Contract [Member]	Dec. 31, 2009 Breach Of Contract [Member]	Jun. 30, 2009 Breach Of Contract [Member]	Apr. 30, 2009 Breach Of Contract [Member]	Dec. 31, 2010 Insurance Settlement [Member]	Dec. 31, 2009 Insurance Settlement [Member]	Dec. 31, 2011 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]	Oct. 16, 2021 Melville Mall [Member] Purchased Call Option [Member]	Oct. 16, 2023 Melville Mall [Member] Put Option [Member]	Dec. 31, 2011 Congressional Plaza [Member] Put Option [Member]	Dec. 31, 2011 Congressional Plaza [Member] Put Option [Member] Minimum [Member]	Dec. 31, 2011 Congressional Plaza [Member] Put Option [Member] Maximum [Member]	Dec. 31, 2011 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, 2011 Obligation To Purchase Member Three Ownership Interest [Member] Montrose Crossing [Member] Put Option [Member]
Loss Contingencies [Line Items]
Loss Contingency, Court Decision, Amount								$ 15,900,000	$ 14,400,000
Loss Contingency, Estimate of Possible Loss						21,400,000	16,400,000
Loss Contingency Accrual, Carrying Value, Period Increase (Decrease)						20,600,000
Final judgment related to a previously disclosed lawsuit					16,200,000					1,000,000	900,000
Warranty Period			10 years	10 years
Product Warranty Accrual	7,100,000	7,200,000
Product Warranty Accrual, Payments	900,000	1,300,000
Letters of Credit Outstanding, Amount	15,900,000
Contractual Obligation												44,500,000
Operating Leases, Future Minimum Payments Due [Abstract]
2012	1,612,000
2013	1,620,000
2014	1,609,000
2015	1,559,000
2016	1,504,000
Thereafter	51,843,000
Total	59,747,000
Purchase Price Under Option													55,000,000	60,000,000	5,000,000	5,000,000								4,900,000
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																		54,000,000	64,000,000
Number of Members With Purchase Options																					2
Operating partnership units, outstanding	360,314
Operating partnership units outstanding, fair value	$ 32,700,000