Commitments and Contingencies	3 Months Ended
Mar. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments In connection with our redevelopment, development and capital improvement activities, we have entered into various construction-related contracts and we have made commitments to complete redevelopment of certain apartment communities, pursuant to financing or other arrangements. As of March 31, 2018, our commitments related to these capital activities totaled approximately $160.0 million, most of which we expect to incur during the next 12 months. We enter into certain commitments for future purchases of goods and services in connection with the operations of our apartment communities. Those commitments generally have terms of one year or less and reflect expenditure levels comparable to our historical expenditures. Tax Credit Arrangements For various consolidated partnerships served by our Asset Management business, we are required to manage the partnerships and related apartment communities in compliance with various laws, regulations and contractual provisions that apply to historic and low-income housing tax credit syndication arrangements. In some instances, noncompliance with applicable requirements could result in projected tax benefits not being realized by the limited partners in these partnerships and would require a refund or reduction of investor capital contributions, which are reported as deferred income in our condensed consolidated balance sheets, until such time as our obligation to deliver tax benefits is relieved. In connection with the expected third quarter sale of our Asset Management business, this obligation will be assumed by the purchaser. Income Taxes In 2014, the Internal Revenue Service initiated an audit of the Aimco Operating Partnership’s 2011 and 2012 tax years. We do not believe the audit will have any material effect on our unrecognized tax benefits, financial condition or results of operations. Legal Matters In addition to the matters described below, we are a party to various legal actions and administrative proceedings arising in the ordinary course of business, some of which are covered by our general liability insurance program, and none of which we expect to have a material adverse effect on our consolidated financial condition, results of operations or cash flows. Environmental Various federal, state and local laws subject apartment community owners or operators to liability for management, and the costs of removal or remediation, of certain potentially hazardous materials that may be present in the land or buildings of an apartment community. Such laws often impose liability without regard to fault or whether the owner or operator knew of, or was responsible for, the presence of such materials. The presence of, or the failure to manage or remediate properly, these materials may adversely affect occupancy at such apartment communities as well as the ability to sell or finance such apartment communities. In addition, governmental agencies may bring claims for costs associated with investigation and remediation actions. Moreover, private plaintiffs may potentially make claims for investigation and remediation costs they incur or for personal injury, disease, disability or other infirmities related to the alleged presence of hazardous materials. In addition to potential environmental liabilities or costs associated with our current apartment communities, we may also be responsible for such liabilities or costs associated with communities we acquire or manage in the future, or apartment communities we no longer own or operate. We are engaged in discussions with the Environmental Protection Agency, or EPA, and the Indiana Department of Environmental Management, or IDEM, regarding contaminated groundwater in a residential area in the vicinity of an Indiana apartment community that has not been owned by us since 2008. The contamination allegedly derives from a dry cleaner that operated on our former property, prior to our ownership. We have undertaken a voluntary remediation of the dry cleaner contamination under IDEM’s oversight, and in previous years accrued our share of the then-estimated cleanup and abatement costs. In 2016, EPA listed our former community and a number of residential communities in the vicinity on the National Priorities List, or NPL (i.e. as a Superfund site), and IDEM has formally sought to terminate us from the voluntary remediation program. We continue discussions with both agencies on potential long-term solutions. We have filed a formal appeal of the EPA listing and the IDEM termination of us from the voluntary remediation program. Although the outcome of these processes are uncertain, we do not expect their resolution to have a material adverse effect on our consolidated financial condition, results of operations or cash flows. We also have been contacted by regulators and the current owner of a property in Lake Tahoe, California, regarding environmental issues allegedly stemming from the historic operation of a dry cleaner. An entity owned by us was the former general partner of a now-dissolved partnership that previously owned a site that was used for dry cleaning. That entity and the current property owner have been remediating the dry cleaner site since 2009, under the oversight of the Lahontan Regional Water Quality Control Board, or Lahontan. In May 2017, Lahontan issued a final cleanup and abatement order that names four potentially-responsible parties, acknowledges that there may be additional responsible parties, and requires the named parties to perform additional groundwater investigation and corrective actions with respect to onsite and offsite contamination. We are appealing the final order while simultaneously complying with it. Although the outcome of this process is uncertain, we do not expect its resolution to have a material adverse effect on our consolidated financial condition, results of operations or cash flows. We have determined that our legal obligations to remove or remediate certain potentially hazardous materials may be conditional asset retirement obligations, as defined in GAAP. Except in limited circumstances where the asset retirement activities are expected to be performed in connection with a planned construction project or apartment community casualty, we believe that the fair value of our asset retirement obligations cannot be reasonably estimated due to significant uncertainties in the timing and manner of settlement of those obligations. Asset retirement obligations that are reasonably estimable as of March 31, 2018, are immaterial to our consolidated financial condition, results of operations and cash flows.

Commitments and Contingencies

Commitments

In connection with our redevelopment, development and capital improvement activities, we have entered into various construction-related contracts and we have made commitments to complete redevelopment of certain apartment communities, pursuant to financing or other arrangements. As of March 31, 2018, our commitments related to these capital activities totaled approximately $160.0 million, most of which we expect to incur during the next 12 months.

We enter into certain commitments for future purchases of goods and services in connection with the operations of our apartment communities. Those commitments generally have terms of one year or less and reflect expenditure levels comparable to our historical expenditures.

Tax Credit Arrangements

For various consolidated partnerships served by our Asset Management business, we are required to manage the partnerships and related apartment communities in compliance with various laws, regulations and contractual provisions that apply to historic and low-income housing tax credit syndication arrangements. In some instances, noncompliance with applicable requirements could result in projected tax benefits not being realized by the limited partners in these partnerships and would require a refund or reduction of investor capital contributions, which are reported as deferred income in our condensed consolidated balance sheets, until such time as our obligation to deliver tax benefits is relieved. In connection with the expected third quarter sale of our Asset Management business, this obligation will be assumed by the purchaser.

Income Taxes

In 2014, the Internal Revenue Service initiated an audit of the Aimco Operating Partnership’s 2011 and 2012 tax years. We do not believe the audit will have any material effect on our unrecognized tax benefits, financial condition or results of operations.

Legal Matters

In addition to the matters described below, we are a party to various legal actions and administrative proceedings arising in the ordinary course of business, some of which are covered by our general liability insurance program, and none of which we expect to have a material adverse effect on our consolidated financial condition, results of operations or cash flows.

Environmental

Various federal, state and local laws subject apartment community owners or operators to liability for management, and the costs of removal or remediation, of certain potentially hazardous materials that may be present in the land or buildings of an apartment community. Such laws often impose liability without regard to fault or whether the owner or operator knew of, or was responsible for, the presence of such materials. The presence of, or the failure to manage or remediate properly, these materials may adversely affect occupancy at such apartment communities as well as the ability to sell or finance such apartment communities. In addition, governmental agencies may bring claims for costs associated with investigation and remediation actions. Moreover, private plaintiffs may potentially make claims for investigation and remediation costs they incur or for personal injury, disease, disability or other infirmities related to the alleged presence of hazardous materials. In addition to potential environmental liabilities or costs associated with our current apartment communities, we may also be responsible for such liabilities or costs associated with communities we acquire or manage in the future, or apartment communities we no longer own or operate.

We are engaged in discussions with the Environmental Protection Agency, or EPA, and the Indiana Department of Environmental Management, or IDEM, regarding contaminated groundwater in a residential area in the vicinity of an Indiana apartment community that has not been owned by us since 2008. The contamination allegedly derives from a dry cleaner that operated on our former property, prior to our ownership. We have undertaken a voluntary remediation of the dry cleaner contamination under IDEM’s oversight, and in previous years accrued our share of the then-estimated cleanup and abatement costs. In 2016, EPA listed our former community and a number of residential communities in the vicinity on the National Priorities List, or NPL (i.e. as a Superfund site), and IDEM has formally sought to terminate us from the voluntary remediation program. We continue discussions with both agencies on potential long-term solutions. We have filed a formal appeal of the EPA listing and the IDEM termination of us from the voluntary remediation program. Although the outcome of these processes are uncertain, we do not expect their resolution to have a material adverse effect on our consolidated financial condition, results of operations or cash flows.

We also have been contacted by regulators and the current owner of a property in Lake Tahoe, California, regarding environmental issues allegedly stemming from the historic operation of a dry cleaner. An entity owned by us was the former general partner of a now-dissolved partnership that previously owned a site that was used for dry cleaning. That entity and the current property owner have been remediating the dry cleaner site since 2009, under the oversight of the Lahontan Regional Water Quality Control Board, or Lahontan. In May 2017, Lahontan issued a final cleanup and abatement order that names four potentially-responsible parties, acknowledges that there may be additional responsible parties, and requires the named parties to perform additional groundwater investigation and corrective actions with respect to onsite and offsite contamination. We are appealing the final order while simultaneously complying with it. Although the outcome of this process is uncertain, we do not expect its resolution to have a material adverse effect on our consolidated financial condition, results of operations or cash flows.

We have determined that our legal obligations to remove or remediate certain potentially hazardous materials may be conditional asset retirement obligations, as defined in GAAP. Except in limited circumstances where the asset retirement activities are expected to be performed in connection with a planned construction project or apartment community casualty, we believe that the fair value of our asset retirement obligations cannot be reasonably estimated due to significant uncertainties in the timing and manner of settlement of those obligations. Asset retirement obligations that are reasonably estimable as of March 31, 2018, are immaterial to our consolidated financial condition, results of operations and cash flows.