Commitments and Contingencies	12 Months Ended
Dec. 31, 2011
Commitments and Contingencies [Abstract]
Commitments and Contingencies	(16) Commitments and Contingencies At December 31, 2011, the Company had six non-cancelable ground leases for certain apartment communities and buildings that expire between 2027 and 2080. Land lease payments are typically the greater of a stated minimum or a percentage of gross rents generated by these apartment communities. Total minimum lease commitments, under land leases and operating leases, are approximately $1.6 million per year for the next five years. To the extent that an environmental matter arises or is identified in the future that has other than a remote risk of having a material impact on the financial statements, the Company will disclose the estimated range of possible outcomes, and, if an outcome is probable, accrue an appropriate liability for remediation and other potential liability. The Company will consider whether such occurrence results in an impairment of value on the affected property and, if so, impairment will be recognized. Except with respect to three communities, the Company has no indemnification agreements from third parties for potential environmental clean-up costs at its communities. The Company has no way of determining at this time the magnitude of any potential liability to which it may be subject arising out of unknown environmental conditions or violations with respect to the communities formerly owned by the Company. No assurance can be given that existing environmental studies with respect to any of the communities reveal all environmental liabilities, that any prior owner or operator of a Property did not create any material environmental condition not known to the Company, or that a material environmental condition does not otherwise exist as to any one or more of the communities. The Company has limited insurance coverage for the types of environmental liabilities described above. The Company has entered into transactions that may require the Company to pay the tax liabilities of the partners in the Operating Partnership or in the DownREIT entities. These transactions are within the Company's control. Although the Company plans to hold the contributed assets or defer recognition of gain on their sale pursuant to like-kind exchange rules under Section 1031 of the Internal Revenue Code the Company can provide no assurance that it will be able to do so and if such tax liabilities were incurred they may to have a material impact on the Company's financial position. There have been a number of lawsuits in recent years against owners and managers of apartment communities alleging personal injury and property damage caused by the presence of mold in residential real estate. Some of these lawsuits have resulted in substantial monetary judgments or settlements. The Company has been sued for mold related matters and has settled some, but not all, of such matters. Insurance carriers have reacted to mold related liability awards by excluding mold related claims from standard policies and pricing mold endorsements at prohibitively high rates. The Company has, however, purchased pollution liability insurance, which includes some coverage for mold. The Company has adopted policies for promptly addressing and resolving reports of mold when it is detected, and to minimize any impact mold might have on residents of the property. The Company believes its mold policies and proactive response to address any known existence, reduces its risk of loss from these cases. There can be no assurances that the Company has identified and responded to all mold occurrences, but the company promptly addresses all known reports of mold. Liabilities resulting from such mold related matters are not expected to have a material adverse effect on the Company's financial condition, results of operations or cash flows. As of December 31, 2011, potential liabilities for mold and other environmental liabilities are not considered probable or the loss cannot be quantified or estimated. The Company carries comprehensive liability, fire, extended coverage and rental loss insurance for each of the communities. Insured risks for comprehensive liabilities covers claims in excess of $25,000 per incident, and property casualty insurance covers losses in excess of a $5.0 million deductible per incident. There are, however, certain types of extraordinary losses, such as, for example, losses from terrorism and earthquake, for which the Company does not have insurance. Substantially all of the communities are located in areas that are subject to earthquakes. The Company provided a loan and construction completion guarantee to the lender in order to fulfill the lender's standard financing requirements related to the construction of the Queen Anne community. The outstanding balance for the construction loan is included in the debt line item in the balance sheet of the co-investments included in Note 3. The construction completion guarantee is for the life of the loan, which is scheduled to mature on July 1, 2014, with two, one-year extension options at the Queen Anne joint venture's option. As of December 31, 2011, the Company was in compliance with all terms of the construction loan and the construction of the community is expected to be completed on time and within budget. The maximum exposure of the guarantee as of December 31, 2011 was $79.1 million based on the construction costs that were budgeted to be incurred to complete the construction. The Company provided a payment guarantee to the counterparties in relation to the total return swaps entered into by the joint venture responsible for the development of the Fountain at La Brea and Santa Monica at La Brea communities. Further the Company has guaranteed completion of development and made certain debt service guarantees for Fountain at La Brea and Santa Monica at La Brea. The outstanding balance for the loans is included in the debt line item in the balance sheet of the co-investments included in Note 3. The payment guarantee is for the payment of the amounts due to the counterparty related total return swaps which are scheduled to mature in September and December 2016. The maximum exposure of the guarantee as of December 31, 2011 was $28.5 million based on the aggregate outstanding debt amount. The Company is subject to various other lawsuits in the normal course of its business operations. Such lawsuits are not expected to have a material adverse effect on the Company's financial condition, results of operations or cash flows.

(16) Commitments and Contingencies

At December 31, 2011, the Company had six non-cancelable ground leases for certain apartment communities and buildings that expire between 2027 and 2080. Land lease payments are typically the greater of a stated minimum or a percentage of gross rents generated by these apartment communities. Total minimum lease commitments, under land leases and operating leases, are approximately $1.6 million per year for the next five years.

To the extent that an environmental matter arises or is identified in the future that has other than a remote risk of having a material impact on the financial statements, the Company will disclose the estimated range of possible outcomes, and, if an outcome is probable, accrue an appropriate liability for remediation and other potential liability. The Company will consider whether such occurrence results in an impairment of value on the affected property and, if so, impairment will be recognized.

Except with respect to three communities, the Company has no indemnification agreements from third parties for potential environmental clean-up costs at its communities. The Company has no way of determining at this time the magnitude of any potential liability to which it may be subject arising out of unknown environmental conditions or violations with respect to the communities formerly owned by the Company. No assurance can be given that existing environmental studies with respect to any of the communities reveal all environmental liabilities, that any prior owner or operator of a Property did not create any material environmental condition not known to the Company, or that a material environmental condition does not otherwise exist as to any one or more of the communities. The Company has limited insurance coverage for the types of environmental liabilities described above.

The Company has entered into transactions that may require the Company to pay the tax liabilities of the partners in the Operating Partnership or in the DownREIT entities. These transactions are within the Company's control. Although the Company plans to hold the contributed assets or defer recognition of gain on their sale pursuant to like-kind exchange rules under Section 1031 of the Internal Revenue Code the Company can provide no assurance that it will be able to do so and if such tax liabilities were incurred they may to have a material impact on the Company's financial position.

There have been a number of lawsuits in recent years against owners and managers of apartment communities alleging personal injury and property damage caused by the presence of mold in residential real estate. Some of these lawsuits have resulted in substantial monetary judgments or settlements. The Company has been sued for mold related matters and has settled some, but not all, of such matters. Insurance carriers have reacted to mold related liability awards by excluding mold related claims from standard policies and pricing mold endorsements at prohibitively high rates. The Company has, however, purchased pollution liability insurance, which includes some coverage for mold. The Company has adopted policies for promptly addressing and resolving reports of mold when it is detected, and to minimize any impact mold might have on residents of the property. The Company believes its mold policies and proactive response to address any known existence, reduces its risk of loss from these cases. There can be no assurances that the Company has identified and responded to all mold occurrences, but the company promptly addresses all known reports of mold. Liabilities resulting from such mold related matters are not expected to have a material adverse effect on the Company's financial condition, results of operations or cash flows. As of December 31, 2011, potential liabilities for mold and other environmental liabilities are not considered probable or the loss cannot be quantified or estimated.

The Company carries comprehensive liability, fire, extended coverage and rental loss insurance for each of the communities. Insured risks for comprehensive liabilities covers claims in excess of $25,000 per incident, and property casualty insurance covers losses in excess of a $5.0 million deductible per incident. There are, however, certain types of extraordinary losses, such as, for example, losses from terrorism and earthquake, for which the Company does not have insurance. Substantially all of the communities are located in areas that are subject to earthquakes.

The Company provided a loan and construction completion guarantee to the lender in order to fulfill the lender's standard financing requirements related to the construction of the Queen Anne community. The outstanding balance for the construction loan is included in the debt line item in the balance sheet of the co-investments included in Note 3. The construction completion guarantee is for the life of the loan, which is scheduled to mature on July 1, 2014, with two, one-year extension options at the Queen Anne joint venture's option. As of December 31, 2011, the Company was in compliance with all terms of the construction loan and the construction of the community is expected to be completed on time and within budget. The maximum exposure of the guarantee as of December 31, 2011 was $79.1 million based on the construction costs that were budgeted to be incurred to complete the construction.

The Company provided a payment guarantee to the counterparties in relation to the total return swaps entered into by the joint venture responsible for the development of the Fountain at La Brea and Santa Monica at La Brea communities. Further the Company has guaranteed completion of development and made certain debt service guarantees for Fountain at La Brea and Santa Monica at La Brea. The outstanding balance for the loans is included in the debt line item in the balance sheet of the co-investments included in Note 3. The payment guarantee is for the payment of the amounts due to the counterparty related total return swaps which are scheduled to mature in September and December 2016. The maximum exposure of the guarantee as of December 31, 2011 was $28.5 million based on the aggregate outstanding debt amount.

The Company is subject to various other lawsuits in the normal course of its business operations. Such lawsuits are not expected to have a material adverse effect on the Company's financial condition, results of operations or cash flows.