Commitments And Contingencies	6 Months Ended
Jun. 30, 2013
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	Commitments and Contingencies As of June 30, 2013, we participate in four real estate ventures structured as DownREIT partnerships that have properties in Arkansas, California, North Carolina, Texas and Utah. As a general partner, we have operating and financial control over these ventures and consolidate them in our consolidated financial statements. These ventures allow the outside limited partners to put their interest in the partnership to us in exchange for our common shares or an equivalent amount in cash. We may acquire any limited partnership interests that are put to the partnership, and we have the option to redeem the interest in cash or a fixed number of our common shares, at our discretion. We also participate in a real estate venture that has a property in Texas that allows its outside partner to put operating partnership units to us. We have the option to redeem these units in cash or a fixed number of our common shares, at our discretion. No common shares were issued in exchange for any of these interests during the six months ended June 30, 2013 and 2012. The aggregate redemption value of these interests was approximately $48 million and $42 million as of June 30, 2013 and December 31, 2012, respectively. We are subject to numerous federal, state and local environmental laws, ordinances and regulations in the areas where we own or operate properties. We are not aware of any contamination which may have been caused by us or any of our tenants that would have a material effect on our consolidated financial statements. As part of our risk management activities, we have applied and been accepted into state sponsored environmental programs which will limit our expenses if contaminants need to be remediated. We also have an environmental insurance policy that covers us against third party liabilities and remediation costs. While we believe that we do not have any material exposure to environmental remediation costs, we cannot give absolute assurance that changes in the law or new discoveries of contamination will not result in additional liabilities to us. During 2011, we filed a lawsuit against our joint venture partner in connection with a development project in Sheridan, Colorado for failure to perform on the joint venture’s past due intercompany note payable to us, which has been eliminated within our consolidated financial statements. We are also involved in one consolidated and two unconsolidated joint ventures with this partner. We are currently in negotiations with our partner; however, we are unable to determine the outcome of the lawsuit or its potential effects on our other joint ventures with this partner. As of June 30, 2013, we have entered into commitments aggregating $68.7 million comprised principally of construction contracts which are generally due in 12 to 36 months. We are also involved in various matters of litigation arising in the normal course of business. While we are unable to predict the amounts involved, our management and counsel are of the opinion that, when such litigation is resolved, any additional liability, if any, will not have a material effect on our consolidated financial statements.

Commitments and Contingencies

As of June 30, 2013, we participate in four real estate ventures structured as DownREIT partnerships that have properties in Arkansas, California, North Carolina, Texas and Utah. As a general partner, we have operating and financial control over these ventures and consolidate them in our consolidated financial statements. These ventures allow the outside limited partners to put their interest in the partnership to us in exchange for our common shares or an equivalent amount in cash. We may acquire any limited partnership interests that are put to the partnership, and we have the option to redeem the interest in cash or a fixed number of our common shares, at our discretion. We also participate in a real estate venture that has a property in Texas that allows its outside partner to put operating partnership units to us. We have the option to redeem these units in cash or a fixed number of our common shares, at our discretion. No common shares were issued in exchange for any of these interests during the six months ended June 30, 2013 and 2012. The aggregate redemption value of these interests was approximately $48 million and $42 million as of June 30, 2013 and December 31, 2012, respectively.

We are subject to numerous federal, state and local environmental laws, ordinances and regulations in the areas where we own or operate properties. We are not aware of any contamination which may have been caused by us or any of our tenants that would have a material effect on our consolidated financial statements.

As part of our risk management activities, we have applied and been accepted into state sponsored environmental programs which will limit our expenses if contaminants need to be remediated. We also have an environmental insurance policy that covers us against third party liabilities and remediation costs.

While we believe that we do not have any material exposure to environmental remediation costs, we cannot give absolute assurance that changes in the law or new discoveries of contamination will not result in additional liabilities to us.

During 2011, we filed a lawsuit against our joint venture partner in connection with a development project in Sheridan, Colorado for failure to perform on the joint venture’s past due intercompany note payable to us, which has been eliminated within our consolidated financial statements. We are also involved in one consolidated and two unconsolidated joint ventures with this partner. We are currently in negotiations with our partner; however, we are unable to determine the outcome of the lawsuit or its potential effects on our other joint ventures with this partner.

As of June 30, 2013, we have entered into commitments aggregating $68.7 million comprised principally of construction contracts which are generally due in 12 to 36 months.

We are also involved in various matters of litigation arising in the normal course of business. While we are unable to predict the amounts involved, our management and counsel are of the opinion that, when such litigation is resolved, any additional liability, if any, will not have a material effect on our consolidated financial statements.