Basis of Presentation (Policies)	6 Months Ended
Jun. 30, 2011
Basis of Presentation (Policies) [Abstract]
Credit quality and the allowance for credit losses	Notes receivable from unconsolidated real estate partnerships and from non-affiliates represent our two portfolio segments (as defined in FASB ASC Topic 310) that we use to evaluate for potential loan loss. Notes receivable from unconsolidated real estate partnerships consist primarily of notes receivable from partnerships in which we are the general partner but do not consolidate the partnership. These loans are typically due on demand, have no stated maturity date and may not require current payments of principal or interest. Notes receivable from non-affiliates have stated maturity dates and may require current payments of principal and interest. Repayment of our notes is subject to a number of variables, including the performance and value of the underlying real estate properties and the claims of unaffiliated mortgage lenders, which are generally senior to our claims. Our notes receivable consist of two classes: loans extended by us that we carry at the face amount plus accrued interest, which we refer to as “par value notes”; and loans extended by predecessors whose positions we generally acquired at a discount, which we refer to as “discounted notes.”
Principles of Consolidation	The accompanying condensed consolidated financial statements include the accounts of Aimco, the Aimco Operating Partnership, and their consolidated entities. We consolidate all variable interest entities for which we are the primary beneficiary. Generally, we consolidate real estate partnerships and other entities that are not variable interest entities when we own, directly or indirectly, a majority voting interest in the entity or are otherwise able to control the entity. All significant intercompany balances and transactions have been eliminated in consolidation.
Variable Interest Entities	We consolidate all variable interest entities for which we are the primary beneficiary. Generally, a variable interest entity, or VIE, is an entity with one or more of the following characteristics: (a) the total equity investment at risk is not sufficient to permit the entity to finance its activities without additional subordinated financial support; (b) as a group, the holders of the equity investment at risk lack (i) the ability to make decisions about an entity’s activities through voting or similar rights, (ii) the obligation to absorb the expected losses of the entity, or (iii) the right to receive the expected residual returns of the entity; or (c) the equity investors have voting rights that are not proportional to their economic interests and substantially all of the entity’s activities either involve, or are conducted on behalf of, an investor that has disproportionately few voting rights. In determining whether we are the primary beneficiary of a VIE, we consider qualitative and quantitative factors, including, but not limited to: which activities most significantly impact the VIE’s economic performance and which party controls such activities; the amount and characteristics of our investment; the obligation or likelihood for us or other investors to provide financial support; and the similarity with and significance to the business activities of us and the other investors. Significant judgments related to these determinations include estimates about the current and future fair values and performance of real estate held by these VIEs and general market conditions.
Derivative Financial Instruments	We have limited exposure to derivative financial instruments. We are contractually obligated on certain of our variable rate debt to limit our exposure to interest rate fluctuations, and we do so by entering into interest rate swap agreements. We primarily use long-term, fixed-rate and self-amortizing non-recourse debt to avoid, among other things, risk related to fluctuating interest rates. For our variable rate debt, we are sometimes required by our lenders to limit our exposure to interest rate fluctuations by entering into interest rate swap agreements, which moderate our exposure to interest rate risk by effectively converting the interest on variable rate debt to a fixed rate. The fair values of the interest rate swaps are reflected as assets or liabilities in the balance sheet, and periodic changes in fair value are included in interest expense or equity, as appropriate.
Fair value Measurements	We measure certain assets and liabilities in our consolidated financial statements at fair value, both on a recurring and nonrecurring basis. Certain of these fair value measurements are based on significant unobservable inputs classified within Level 3 of the valuation hierarchy defined in FASB ASC Topic 820. When a determination is made to classify a fair value measurement within Level 3 of the valuation hierarchy, the determination is based upon the significance of the unobservable factors to the overall fair value measurement. However, Level 3 fair value measurements typically also include observable components that can be validated to observable external sources; accordingly, the changes in fair value in the table below are due in part to observable factors that are part of the valuation methodology.
Income Taxes	In March 2008, we were notified by the Internal Revenue Service, or the IRS, that it intended to examine the 2006 Federal tax return for the Aimco Operating Partnership. During June 2008, the IRS issued AIMCO-GP, Inc., the general partner and tax matters partner of the Aimco Operating Partnership, a summary report including the IRS’s proposed adjustments to the Aimco Operating Partnership’s 2006 Federal tax return. In addition, in May 2009, we were notified by the IRS that it intended to examine the 2007 Federal tax return for the Aimco Operating Partnership. During November 2009, the IRS issued AIMCO-GP, Inc. a summary report including the IRS’s proposed adjustments to the Aimco Operating Partnership’s 2007 Federal tax return. The matter is currently pending administratively before IRS Appeals and the IRS has made no determination. We do not expect the 2006 or 2007 proposed adjustments to have any material effect on our unrecognized tax benefits, financial condition or results of operations.
Use of Estimates	The preparation of our condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts included in the financial statements and accompanying notes thereto. Actual results could differ from those estimates.
Earnings (Loss) Per Share	We calculate earnings (loss) per share based on the weighted average number of shares of Common Stock, participating securities, common stock equivalents and dilutive convertible securities outstanding during the period. The following table illustrates the calculation of basic and diluted earnings (loss) per share for the three and six months ended June 30, 2011 and 2010 (in thousands, except per share data):
Real Estate Dispositions (Discontinued Operations)	We are currently marketing for sale certain real estate properties that are inconsistent with our long-term investment strategy. At the end of each reporting period, we evaluate whether such properties meet the criteria to be classified as held for sale, including whether such properties are expected to be sold within 12 months. Additionally, certain properties that do not meet all of the criteria to be classified as held for sale at the balance sheet date may nevertheless be sold and included in discontinued operations in the subsequent 12 months; thus, the number of properties that may be sold during the subsequent 12 months could exceed the number classified as held for sale. At June 30, 2011 and December 31, 2010, we had two and 29 properties, with an aggregate of 710 and 4,750 units, respectively, classified as held for sale. Amounts classified as held for sale in the accompanying condensed consolidated balance sheets are as follows (in thousands):
Notes Receivable	We assess the collectibility of notes receivable on a periodic basis, which assessment consists primarily of an evaluation of cash flow projections of the borrower to determine whether estimated cash flows are sufficient to repay principal and interest in accordance with the contractual terms of the note. We update our cash flow projections of the borrowers annually, and more frequently for certain loans depending on facts and circumstances. We recognize provisions for losses on notes receivable when it is probable that principal and interest will not be received in accordance with the contractual terms of the loan. Factors that affect this assessment include the fair value of the partnership’s real estate, pending transactions to refinance the partnership’s senior obligations or sell the partnership’s real estate, and market conditions (current and forecasted) related to a particular asset. The amount of the provision to be recognized generally is based on the fair value of the partnership’s real estate that represents the primary source of loan repayment. In certain instances where other sources of cash flow are available to repay the loan, the provision is measured by discounting the estimated cash flows at the loan’s original effective interest rate.
Business Segments	Our chief executive officer, who is our chief operating decision maker, uses various generally accepted industry financial measures to assess the performance and financial condition of the business, including: Net Asset Value, which is the estimated fair value of our assets, net of liabilities and preferred equity; Pro forma Funds From Operations, which is Funds From Operations excluding operating real estate impairment losses and preferred equity redemption related amounts; Adjusted Funds From Operations, which is Pro forma Funds From Operations less spending for Capital Replacements; property net operating income, which is rental and other property revenues less direct property operating expenses, including real estate taxes; proportionate property net operating income, which reflects our share of property net operating income of our consolidated and unconsolidated properties; same store property operating results; Free Cash Flow, which is net operating income less spending for Capital Replacements; Free Cash Flow internal rate of return; financial coverage ratios; and leverage as shown on our balance sheet. Our chief operating decision maker emphasizes proportionate property net operating income as a key measurement of segment profit or loss.
Basis of Presentation	The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, have been condensed or omitted in accordance with such rules and regulations, although management believes the disclosures are adequate to prevent the information presented from being misleading. In the opinion of management, all adjustments (consisting of normal recurring items) considered necessary for a fair presentation have been included. Operating results for the three and six months ended June 30, 2011, are not necessarily indicative of the results that may be expected for the year ending December 31, 2011.

Basis of Presentation (Policies)

6 Months Ended

Jun. 30, 2011

Basis of Presentation (Policies) [Abstract]

Credit quality and the allowance for credit losses

Notes receivable from unconsolidated real estate partnerships and from non-affiliates represent our two portfolio segments (as defined in FASB ASC Topic 310) that we use to evaluate for potential loan loss. Notes receivable from unconsolidated real estate partnerships consist primarily of notes receivable from partnerships in which we are the general partner but do not consolidate the partnership. These loans are typically due on demand, have no stated maturity date and may not require current payments of principal or interest. Notes receivable from non-affiliates have stated maturity dates and may require current payments of principal and interest. Repayment of our notes is subject to a number of variables, including the performance and value of the underlying real estate properties and the claims of unaffiliated mortgage lenders, which are generally senior to our claims. Our notes receivable consist of two classes: loans extended by us that we carry at the face amount plus accrued interest, which we refer to as “par value notes”; and loans extended by predecessors whose positions we generally acquired at a discount, which we refer to as “discounted notes.”

Principles of Consolidation

The accompanying condensed consolidated financial statements include the accounts of Aimco, the Aimco Operating Partnership, and their consolidated entities. We consolidate all variable interest entities for which we are the primary beneficiary. Generally, we consolidate real estate partnerships and other entities that are not variable interest entities when we own, directly or indirectly, a majority voting interest in the entity or are otherwise able to control the entity. All significant intercompany balances and transactions have been eliminated in consolidation.

Variable Interest Entities

We consolidate all variable interest entities for which we are the primary beneficiary. Generally, a variable interest entity, or VIE, is an entity with one or more of the following characteristics: (a) the total equity investment at risk is not sufficient to permit the entity to finance its activities without additional subordinated financial support; (b) as a group, the holders of the equity investment at risk lack (i) the ability to make decisions about an entity’s activities through voting or similar rights, (ii) the obligation to absorb the expected losses of the entity, or (iii) the right to receive the expected residual returns of the entity; or (c) the equity investors have voting rights that are not proportional to their economic interests and substantially all of the entity’s activities either involve, or are conducted on behalf of, an investor that has disproportionately few voting rights.

In determining whether we are the primary beneficiary of a VIE, we consider qualitative and quantitative factors, including, but not limited to: which activities most significantly impact the VIE’s economic performance and which party controls such activities; the amount and characteristics of our investment; the obligation or likelihood for us or other investors to provide financial support; and the similarity with and significance to the business activities of us and the other investors. Significant judgments related to these determinations include estimates about the current and future fair values and performance of real estate held by these VIEs and general market conditions.

Derivative Financial Instruments

We have limited exposure to derivative financial instruments. We are contractually obligated on certain of our variable rate debt to limit our exposure to interest rate fluctuations, and we do so by entering into interest rate swap agreements. We primarily use long-term, fixed-rate and self-amortizing non-recourse debt to avoid, among other things, risk related to fluctuating interest rates. For our variable rate debt, we are sometimes required by our lenders to limit our exposure to interest rate fluctuations by entering into interest rate swap agreements, which moderate our exposure to interest rate risk by effectively converting the interest on variable rate debt to a fixed rate. The fair values of the interest rate swaps are reflected as assets or liabilities in the balance sheet, and periodic changes in fair value are included in interest expense or equity, as appropriate.

Fair value Measurements

We measure certain assets and liabilities in our consolidated financial statements at fair value, both on a recurring and nonrecurring basis. Certain of these fair value measurements are based on significant unobservable inputs classified within Level 3 of the valuation hierarchy defined in FASB ASC Topic 820. When a determination is made to classify a fair value measurement within Level 3 of the valuation hierarchy, the determination is based upon the significance of the unobservable factors to the overall fair value measurement. However, Level 3 fair value measurements typically also include observable components that can be validated to observable external sources; accordingly, the changes in fair value in the table below are due in part to observable factors that are part of the valuation methodology.

Income Taxes

In March 2008, we were notified by the Internal Revenue Service, or the IRS, that it intended to examine the 2006 Federal tax return for the Aimco Operating Partnership. During June 2008, the IRS issued AIMCO-GP, Inc., the general partner and tax matters partner of the Aimco Operating Partnership, a summary report including the IRS’s proposed adjustments to the Aimco Operating Partnership’s 2006 Federal tax return. In addition, in May 2009, we were notified by the IRS that it intended to examine the 2007 Federal tax return for the Aimco Operating Partnership. During November 2009, the IRS issued AIMCO-GP, Inc. a summary report including the IRS’s proposed adjustments to the Aimco Operating Partnership’s 2007 Federal tax return. The matter is currently pending administratively before IRS Appeals and the IRS has made no determination. We do not expect the 2006 or 2007 proposed adjustments to have any material effect on our unrecognized tax benefits, financial condition or results of operations.

Use of Estimates

The preparation of our condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts included in the financial statements and accompanying notes thereto. Actual results could differ from those estimates.

Earnings (Loss) Per Share

We calculate earnings (loss) per share based on the weighted average number of shares of Common Stock, participating securities, common stock equivalents and dilutive convertible securities outstanding during the period. The following table illustrates the calculation of basic and diluted earnings (loss) per share for the three and six months ended June 30, 2011 and 2010 (in thousands, except per share data):

Real Estate Dispositions (Discontinued Operations)

We are currently marketing for sale certain real estate properties that are inconsistent with our long-term investment strategy. At the end of each reporting period, we evaluate whether such properties meet the criteria to be classified as held for sale, including whether such properties are expected to be sold within 12 months. Additionally, certain properties that do not meet all of the criteria to be classified as held for sale at the balance sheet date may nevertheless be sold and included in discontinued operations in the subsequent 12 months; thus, the number of properties that may be sold during the subsequent 12 months could exceed the number classified as held for sale. At June 30, 2011 and December 31, 2010, we had two and 29 properties, with an aggregate of 710 and 4,750 units, respectively, classified as held for sale. Amounts classified as held for sale in the accompanying condensed consolidated balance sheets are as follows (in thousands):

Notes Receivable

We assess the collectibility of notes receivable on a periodic basis, which assessment consists primarily of an evaluation of cash flow projections of the borrower to determine whether estimated cash flows are sufficient to repay principal and interest in accordance with the contractual terms of the note. We update our cash flow projections of the borrowers annually, and more frequently for certain loans depending on facts and circumstances. We recognize provisions for losses on notes receivable when it is probable that principal and interest will not be received in accordance with the contractual terms of the loan. Factors that affect this assessment include the fair value of the partnership’s real estate, pending transactions to refinance the partnership’s senior obligations or sell the partnership’s real estate, and market conditions (current and forecasted) related to a particular asset. The amount of the provision to be recognized generally is based on the fair value of the partnership’s real estate that represents the primary source of loan repayment. In certain instances where other sources of cash flow are available to repay the loan, the provision is measured by discounting the estimated cash flows at the loan’s original effective interest rate.

Business Segments

Our chief executive officer, who is our chief operating decision maker, uses various generally accepted industry financial measures to assess the performance and financial condition of the business, including: Net Asset Value, which is the estimated fair value of our assets, net of liabilities and preferred equity; Pro forma Funds From Operations, which is Funds From Operations excluding operating real estate impairment losses and preferred equity redemption related amounts; Adjusted Funds From Operations, which is Pro forma Funds From Operations less spending for Capital Replacements; property net operating income, which is rental and other property revenues less direct property operating expenses, including real estate taxes; proportionate property net operating income, which reflects our share of property net operating income of our consolidated and unconsolidated properties; same store property operating results; Free Cash Flow, which is net operating income less spending for Capital Replacements; Free Cash Flow internal rate of return; financial coverage ratios; and leverage as shown on our balance sheet. Our chief operating decision maker emphasizes proportionate property net operating income as a key measurement of segment profit or loss.

Basis of Presentation

The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America, or GAAP, have been condensed or omitted in accordance with such rules and regulations, although management believes the disclosures are adequate to prevent the information presented from being misleading. In the opinion of management, all adjustments (consisting of normal recurring items) considered necessary for a fair presentation have been included. Operating results for the three and six months ended June 30, 2011, are not necessarily indicative of the results that may be expected for the year ending December 31, 2011.