Apartment Investment and Management (AIV) 10-K 12 Mar 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2020	Mar. 10, 2021	Jun. 30, 2020
Document Information [Line Items]
Entity Registrant Name	Apartment Investment and Management Company
Entity Central Index Key	0000922864
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Small Business	false
Entity Shell Company	false
Trading Symbol	AIV
Entity File Number	1-13232
Entity Tax Identification Number	84-1259577
Entity Address, State or Province	MD
Entity Address, Address Line One	4582 South Ulster Street
Entity Address, Address Line Two	Suite 1450
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80237
City Area Code	303
Local Phone Number	224-7900
Entity Common Stock, Shares Outstanding		149,208,479
Title of 12(b) Security	Class A Common Stock (Apartment Investment and Management Company)
Security Exchange Name	NYSE
Document Annual Report	true
Document Transition Report	false
ICFR Auditor Attestation Flag	false
Documents Incorporated by Reference	Portions of Part III will be incorporated by reference in accordance with Instruction G (3) to Form 10-K no later than 120 days after the end of the registrant’s fiscal year.
Entity Public Float			$ 5.6
Aimco OP L.P. [Member]
Document Information [Line Items]
Entity Registrant Name	Aimco OP L.P.
Entity Central Index Key	0001820878
Document Type	10-K
Document Period End Date	Dec. 31, 2020
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Small Business	false
Entity Shell Company	false
Entity File Number	0-56223
Entity Tax Identification Number	85-2460835
Entity Address, State or Province	DE
Entity Address, Address Line One	4582 South Ulster Street
Entity Address, Address Line Two	Suite 1450
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80237
City Area Code	303
Local Phone Number	224-7900
ICFR Auditor Attestation Flag	true

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
ASSETS
Buildings and improvements	$ 995,116	$ 937,532
Land	505,153	447,880
Total real estate	1,500,269	1,385,412
Accumulated depreciation	(495,010)	(449,444)
Net real estate	1,005,259	935,968
Cash and cash equivalents	289,582	5,403
Restricted cash	9,153	4,717
Mezzanine investment	307,362	280,258
Unconsolidated real estate partnerships	12,829	12,741
Notes receivable	37,045	0
Right-of-use lease assets	98,280	0
Due from affiliates	4,333	0
Other assets, net	63,334	21,038
Total assets	1,840,492	1,260,125
LIABILITIES AND EQUITY
Non-recourse property debt, net	447,967	492,638
Notes Payable to AIR	534,127	66,295
Total indebtedness	982,094	558,933
Deferred tax liabilities, net	131,560	148,227
Lease liabilities	100,496	0
Due to affiliates	5,897	0
Accrued liabilities and other	57,091	34,685
Total liabilities	1,277,138	741,845
Redeemable noncontrolling interest in consolidated real estate partnership	4,263	4,720
Commitments and contingencies (Note 15)
Equity:
Aimco Predecessor equity	0	513,264
Common Stock, $0.01 par value, 510,587,500 and 0 shares authorized at December 31, 2020 and 2019, respectively, and 149,036,263 and 0 shares issued and outstanding at December 31, 2020 and 2019, respectively	1,490	0
Additional paid-in capital	515,127	0
Accumulated deficit	(16,839)	0
Total Aimco equity	499,778	513,264
Noncontrolling interests in consolidated real estate partnerships	31,877	108
Common noncontrolling interests in Aimco Operating Partnership	27,436	188
Total equity	559,091	513,560
Total liabilities and equity	1,840,492	1,260,125
Aimco OP L.P. [Member]
ASSETS
Buildings and improvements	995,116	937,532
Land	505,153	447,880
Total real estate	1,500,269	1,385,412
Accumulated depreciation	(495,010)	(449,444)
Net real estate	1,005,259	935,968
Cash and cash equivalents	289,582	5,403
Restricted cash	9,153	4,717
Mezzanine investment	307,362	280,258
Unconsolidated real estate partnerships	12,829	12,741
Notes receivable	37,045	0
Right-of-use lease assets	98,280	0
Due from affiliates	4,333	0
Other assets, net	63,334	21,038
Total assets	1,840,492	1,260,125
LIABILITIES AND EQUITY
Non-recourse property debt, net	447,967	492,638
Notes Payable to AIR	534,127	66,295
Total indebtedness	982,094	558,933
Deferred tax liabilities, net	131,560	148,227
Lease liabilities	100,496	0
Due to affiliates	5,897	0
Accrued liabilities and other	57,091	34,685
Total liabilities	1,277,138	741,845
Redeemable noncontrolling interest in consolidated real estate partnership	4,263	4,720
Commitments and contingencies (Note 15)	0	0
Equity:
Aimco Predecessor equity	0	513,264
Noncontrolling interests in consolidated real estate partnerships	31,877	108
General Partner and Special Limited Partner	499,778	0
Limited Partners	27,436	188
Partners' capital attributable to Aimco Operating Partnership	527,214	513,452
Total partners' capital attributable to Aimco Operating Partnership	559,091	513,560
Total liabilities and partners' capital	1,840,492	1,260,125
Interest Rate Options
ASSETS
Interest rate option	13,315	0
Interest Rate Options | Aimco OP L.P. [Member]
ASSETS
Interest rate option	$ 13,315	$ 0

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Dec. 31, 2020	Dec. 31, 2019
Statement Of Financial Position [Abstract]
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (in shares)	510,587,500	0
Common Stock, shares issued (in shares)	149,036,263	0
Common Stock, shares outstanding (in shares)	149,036,263	0

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REVENUES:
Rental and other property revenues	$ 151,451	$ 143,692	$ 132,163
OPERATING EXPENSES:
Property operating expenses	61,514	57,541	53,552
Depreciation and amortization	77,965	64,030	49,375
Impairment	15,860
General and administrative expenses	10,469	7,062	5,766
Total operating expenses	165,808	128,633	108,693
Interest income	110	26	8
Interest expense	(27,512)	(18,598)	(19,643)
Mezzanine investment income, net	27,576	1,531
Income from unconsolidated real estate partnerships	808	935	940
Other expenses, net	(2,545)	(2,141)	(1,103)
(Loss) income before income tax benefit (expense)	(15,920)	(3,188)	3,672
Income tax benefit (expense)	10,149	3,301	(261)
Net (loss) income	(5,771)	113	3,411
Net loss attributable to redeemable noncontrolling interest in consolidated real estate partnership	457	191
Net loss attributable to noncontrolling interests in consolidated real estate partnerships	4	15	5
Net loss (income) attributable to common noncontrolling interests in Aimco Operating Partnership	269	(15)	(173)
Net (loss) income attributable to common stockholders	$ (5,041)	$ 304	$ 3,243
Net (loss) income per common share – basic	$ (0.03)	$ 0	$ 0.02
Net (loss) income per common share – diluted	$ (0.03)	$ 0	$ 0.02
Weighted-average common shares outstanding – basic	148,569,000	148,549,000	148,549,000
Weighted-average common shares outstanding – diluted	148,569,000	148,569,000	148,569,000
AIMCO Properties, LP [Member]
REVENUES:
Rental and other property revenues	$ 151,451	$ 143,692	$ 132,163
OPERATING EXPENSES:
Property operating expenses	61,514	57,541	53,552
Depreciation and amortization	77,965	64,030	49,375
Impairment	15,860
General and administrative expenses	10,469	7,062	5,766
Total operating expenses	165,808	128,633	108,693
Interest income	110	26	8
Interest expense	(27,512)	(18,598)	(19,643)
Mezzanine investment income, net	27,576	1,531
Other expenses, net	(2,545)	(2,141)	(1,103)
(Loss) income before income tax benefit (expense)	(15,920)	(3,188)	3,672
Income tax benefit (expense)	10,149	3,301	(261)
Net (loss) income	(5,771)	113	3,411
Net loss attributable to noncontrolling interests in consolidated real estate partnerships	4	15	5
Net loss (income) attributable to common noncontrolling interests in Aimco Operating Partnership	457	191
Net (loss) income attributable to common stockholders	$ (5,310)	$ 319	$ 3,416
Net (loss) income per common share – basic	$ (0.03)	$ 0	$ 0.02
Net (loss) income per common share – diluted	$ (0.03)	$ 0	$ 0.02
Weighted-average common shares outstanding – basic	156,500,000	156,480,000	156,480,000
Weighted-average common shares outstanding – diluted	156,500,000	156,500,000	156,500,000
AIMCO Properties, LP [Member] | Unconsolidated Real Estate Partnerships [Member]
OPERATING EXPENSES:
Mezzanine investment income, net	$ 808	$ 935	$ 940

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	AIMCO Properties, LP [Member]	Common Stock	Common Noncontrolling Interests In Aimco Operating Partnership	Common Noncontrolling Interests In Aimco Operating Partnership	Additional Paid-in Capital	Aimco Predecessor Equity	Aimco Predecessor EquityAIMCO Properties, LP [Member]	Accumulated Deficit
Balances at Dec. 31, 2017	$ 284,306			$ 128			$ 284,178
Net income attributable to Aimco Predecessor, net	3,243	$ 3,243						$ 3,243
Net loss attributable to noncontrolling interests in consolidated real estate partnerships	(5)			(5)
Net loss attributable to common noncontrolling interests in Aimco Operating Partnership	173				$ 173
Contribution (Distributions) to Predecessor, net	(60,241)	(60,241)					(60,241)
Balances at Dec. 31, 2018	227,476			123	173		227,180
Net income attributable to Aimco Predecessor, net	304	304						304
Net loss attributable to noncontrolling interests in consolidated real estate partnerships	(15)			(15)
Net loss attributable to common noncontrolling interests in Aimco Operating Partnership	15				15
Contribution (Distributions) to Predecessor, net	285,780	285,780					285,780
Balances at Dec. 31, 2019	513,560			108	188		513,264
Net income attributable to Aimco Predecessor, net	(5,041)	11,798						$ 11,798
Net loss attributable to Aimco common stockholders	(16,839)								$ (16,839)
Net loss attributable to noncontrolling interests in consolidated real estate partnerships	(4)			(4)
Net loss attributable to common noncontrolling interests in Aimco Operating Partnership	(269)				(269)
Contribution (Distributions) to Predecessor, net	18,249	18,249					18,249
Issuance of equity in connection with Separation			$ 1,488		27,517	$ 514,306	$ (543,311)
Issuance of Common Stock in connection with separation (In share)			148,866
Contributions from noncontrolling interests	31,773	$ 31,773		31,773
Other Common Stock issuances	823		$ 2			821
Other Common Stock issuances (In share)			170
Balances at Dec. 31, 2020	$ 559,091		$ 1,490	$ 31,877	$ 27,436	$ 515,127			$ (16,839)
Balances (in shares) at Dec. 31, 2020			149,036

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	$ (5,771)	$ 113	$ 3,411
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	77,965	64,030	49,375
Income from unconsolidated real estate partnerships	(27,576)	(1,531)
Income tax (benefit) expense	(10,149)	(3,301)	261
Impairment	15,860
Amortization of debt issuance costs and other	368	446	647
Mezzanine investment, net	(27,576)	(1,531)
Unrealized gain on interest rate option	1,058
Changes in operating assets and operating liabilities:
Accounts receivable and other	(1,873)	1,652	427
Accounts payable, accrued liabilities and other	(1,228)	(2,545)	305
Total adjustments	53,617	57,816	50,075
Net cash provided by operating activities	47,846	57,929	53,486
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate	(107,908)	(95,895)
Capital expenditures	(23,889)	(39,334)	(37,844)
Payment for mezzanine investment and related transaction costs		(277,627)
Other investing activities	2,472
Net cash used in investing activities	(129,325)	(412,856)	(37,844)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from non-recourse property debt	40,000	62,480	93,280
Principal repayments on non-recourse property debt	(84,193)	(57,875)	(118,009)
Proceeds from Notes Payable to AIR		66,295
Purchase of interest rate option	(12,245)
Change in Aimco Predecessor investment, net	420,929	285,745	11,073
Contribution from noncontrolling interests in consolidated real estate partnerships	20,106	4,911
Other financing activities	(14,503)	(1,314)	(2,267)
Net cash provided by (used in) financing activities	370,094	360,242	(15,923)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	288,615	5,315	(281)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD	10,120	4,805	5,086
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	298,735	10,120	4,805
AIMCO Properties, LP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net (loss) income	(5,771)	113	3,411
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Depreciation and amortization	77,965	64,030	49,375
Income from unconsolidated real estate partnerships	(27,576)	(1,531)
Income tax (benefit) expense	(10,149)	(3,301)	261
Impairment	15,860
Amortization of debt issuance costs and other	368	446	647
Mezzanine investment, net	(27,576)	(1,531)
Unrealized gain on interest rate option	1,058
Changes in operating assets and operating liabilities:
Accounts receivable and other	(1,873)	1,652	427
Accounts payable, accrued liabilities and other	(1,228)	(2,545)	305
Total adjustments	53,617	57,816	50,075
Net cash provided by operating activities	47,846	57,929	53,486
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate	(107,908)	(95,895)
Capital expenditures	(23,889)	(39,334)	(37,844)
Payment for mezzanine investment and related transaction costs		(277,627)
Other investing activities	2,472
Net cash used in investing activities	(129,325)	(412,856)	(37,844)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from non-recourse property debt	40,000	62,480	93,280
Principal repayments on non-recourse property debt	(84,193)	(57,875)	(118,009)
Proceeds from Note Payable to AIR		66,295
Purchase of interest rate option	(12,245)
Change in Aimco Predecessor investment, net	420,929	285,745	11,073
Contribution from noncontrolling interests in consolidated real estate partnerships	20,106	4,911
Other financing activities	(14,503)	(1,314)	(2,267)
Net cash provided by (used in) financing activities	370,094	360,242	(15,923)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	288,615	5,315	(281)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD	10,120	4,805	5,086
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	298,735	10,120	4,805
Unconsolidated Real Estate Partnerships [Member]
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Income from unconsolidated real estate partnerships	(808)	(935)	(940)
Unconsolidated Real Estate Partnerships [Member] | AIMCO Properties, LP [Member]
Adjustments to reconcile net (loss) income to net cash provided by operating activities:
Income from unconsolidated real estate partnerships	$ (808)	$ (935)	$ (940)

Consolidated Statements of Part

Consolidated Statements of Partners' Capital - USD ($) $ in Thousands	Total	AIMCO Properties, LP [Member]	General Partner and Special Limited Partner [Member]AIMCO Properties, LP [Member]	Limited Partners [Member]AIMCO Properties, LP [Member]	Partners Capital Attributable To The Partnership [Member]AIMCO Properties, LP [Member]	Common Noncontrolling Interests In Aimco Operating PartnershipAIMCO Properties, LP [Member]	Aimco Predecessor Capital [Member]AIMCO Properties, LP [Member]
Balances at Dec. 31, 2017		$ 284,306				$ 128	$ 284,178
Net income attributable to Aimco Predecessor		3,416		$ 173	$ 173		3,243
Net loss attributable to noncontrolling interests in consolidated real estate partnerships		(5)				(5)
Contribution (Distributions) to Predecessor, net	$ (60,241)	(60,241)					(60,241)
Balances at Dec. 31, 2018		227,476		173	173	123	227,180
Net income attributable to Aimco Predecessor		319		15	15		304
Net loss attributable to noncontrolling interests in consolidated real estate partnerships		(15)				(15)
Contribution (Distributions) to Predecessor, net	285,780	285,780					285,780
Balances at Dec. 31, 2019		513,560		188	188	108	513,264
Net income attributable to Aimco Predecessor		12,460		662	662		11,798
Net Ioss		(17,770)	$ (16,839)	(931)	(17,770)
Net loss attributable to noncontrolling interests in consolidated real estate partnerships		(4)				(4)
Contribution (Distributions) to Predecessor, net	18,249	18,249					18,249
Issuance of partners' capital in connection with Separation			515,794	27,517	543,311		$ (543,311)
Contributions from noncontrolling interests	$ 31,773	31,773				31,773
Other issuances of common partnership units to Aimco		823	823		823
Balances at Dec. 31, 2020		$ 559,091	$ 499,778	$ 27,436	$ 527,214	$ 31,877

Basis of Presentation and Organ

Basis of Presentation and Organization	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Organization	Note 1 — Basis of Presentation and Organization Basis of Presentation The accompanying consolidated financial statements include the accounts of Apartment Investment and Management Company (“Aimco”), AIMCO OP L.P. (“Aimco Operating Partnership”) and their consolidated subsidiaries. The Aimco Operating Partnership’s consolidated financial statements include the accounts of the Aimco Operating Partnership and its consolidated subsidiaries. All significant intercompany balances have been eliminated in consolidation. Except as the context otherwise requires, “we,” “us,” and “our,” refer to Aimco, the Aimco Operating Partnership, and their consolidated entities. The Separation On December 15, 2020, Aimco completed the separation of its businesses (the “Separation”), creating two, separate and distinct, publicly traded companies, Aimco and Apartment Income REIT Corp. (“AIR”). Notwithstanding the legal form of the Separation, for accounting and financial reporting purposes, Aimco is presented as being spun-off from AIR. This presentation is in accordance with generally accepted accounting principles in the U.S. (“GAAP”), and is due primarily to the relative significance of Aimco’s business, as measured in terms of revenues, net income, assets, and other relevant indicators, as compared to those indicators for AIR before the Separation. Therefore, Aimco is the accounting spinnee and AIR is considered the divesting entity and is treated as the accounting spinnor (Aimco and AIR together, as they existed prior to the Separation, “Aimco Predecessor”). P rior to the Separation, the consolidated financial statements were prepared on a carve-out basis and reflect significant assumptions and allocations. The consolidated financial statements reflect our historical consolidated financial position, results of operations, and cash flows in conformity with U.S. GAAP. The historical financial statements of Aimco do not represent the financial position and results of operations of one legal entity, but r All separation related transactions between Aimco and Aimco Predecessor are considered effectively settled through partners’ capital in our consolidated financial statements, other than the Notes Payable to AIR as discussed in Note 8. The settlement of these transactions is reflected as net contributions from and distributions to Aimco Predecessor in our consolidated statements of equity and partners’ capital and net change in Aimco Predecessor invesment in our consolidated statements of cash flows as financing activities. Organization and Business Aimco, a Maryland corporation incorporated on January 10, 1994, is a self-administered and self-managed real estate investment trust (“REIT”). Aimco, through a wholly-owned subsidiary, is the general and special limited partner of the Aimco Operating Partnership. As of December 31, 2020, Aimco owned approximately 93.2% of the legal interest in the common partnership units of the Aimco Operating Partnership and 94.8% of the economic interest in the Aimco Operating Partnership. The remaining 6.8% legal interest is owned by limited partners. As the sole general partner of the Aimco Operating Partnership, Aimco has exclusive control of the Aimco Operating Partnership’s day-to-day management. Following the completion of the Separation, we retained the development and redevelopment business of Aimco, 25 consolidated communities including 16 multi-family communities securing $534.1 million of Notes Payable to AIR, and four partially-owned communities that we do not consolidate. In the fourth quarter of 2020 we entered into a joint venture for the development of a property located in the Washington, D.C. area. In addition, we hold other opportunistic investments including 1001 Brickell Bay Drive; our indirect interest in the loan to, and the equity option in, Maximus PM Mezzanine A LLC, the partnership that owns Parkmerced Apartments (the “Mezzanine Investment”); and our IQHQ, Inc. (“IQHQ”) investment. We own and operate a portfolio of apartment communities, diversified by both geography and price point in 12 states and the District of Columbia. As of December 31, 2020, our portfolio included 27 properties with 6,342 apartment homes. Any reference to the number of apartment communities and homes, square footage, or occupancy percentage in these notes to our consolidated financial statements are unaudited.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Note 2 — Basis of Presentation and Summary of Significant Accounting Policies Principles of Consolidation We consolidate variable interest entities (“VIE”), in which we are considered the primary beneficiary. The primary beneficiary is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. As used herein, and except where the context otherwise requires, “partnership” refers to a limited partnership or a limited liability company and “partner” refers to a partner in a limited partnership or a member of a limited liability company. Certain reclassifications have been made to prior period amounts to conform to the current period financial statement presentation with no effect on the Company’s previously reported results of operations, financial position, or cash flows. Allocations The consolidated statements of operations include allocations of general and administrative expenses from Aimco Predecessor, as discussed in Note 5 —Transactions with AIR. We consider the basis on which expenses have been allocated to be a reasonable reflection of the utilization of services provided to or the benefit received by us during the periods presented. However, the allocations may not include all the actual expenses that we would have incurred and may not reflect our consolidated results of operations, financial position, and cash flows had it been a stand-alone company during the periods presented. Actual costs that might have been incurred had we been a stand-alone company would depend on a number of factors, including the chosen organizational structure, what functions we might have performed ourselves or outsourced, and strategic decisions we might have made in areas such as information technology and infrastructure. Following the Separation, AIR, through its subsidiaries, provides Aimco with certain property management and other services, and we perform certain functions using our own resources or purchase services from third parties. Common Noncontrolling Interests in Aimco Operating Partnership Common noncontrolling interests in Aimco Operating Partnership consist of common OP Units and are reflected in Aimco’s accompanying consolidated balance sheets as common noncontrolling interests in Aimco Operating Partnership. The Aimco Operating Partnership’s income or loss is allocated to the holders of common OP Units, other than Aimco, based on the weighted-average number of common OP Units (including Aimco) outstanding during the period. During the years ended December 31, 2020, 2019, and 2018, the holders of common OP Units had a weighted-average economic ownership interest in the Aimco Operating Partnership of 5.4% Redeemable Noncontrolling Interest in Consolidated Real Estate Partnerships Redeemable noncontrolling interest consists of equity interests held by a limited partner in a consolidated real estate partnership that has a finite life. We generally attribute to noncontrolling interests their share of income or loss of consolidated partnerships based on their proportionate interest in the results of operations of the partnerships, including their share of losses even if such attribution results in a deficit noncontrolling interest balance within our equity accounts. If a real estate partnership includes redemption rights that are not within our control, the noncontrolling interest is included as temporary equity. If the redemption right is not currently redeemable but probable of being redeemable in the future, changes in redemption value are recognized each quarter with the change in value being reflected in additional paid-in-capital. The assets of our consolidated real estate partnerships must first be used to settle the liabilities of the consolidated real estate partnerships. The consolidated real estate partnership’s creditors do not have recourse to the general credit of the Aimco Operating Partnership. The following table represents a reconciliation of our redeemable noncontrolling interest in consolidated real estate partnerships during the year ended December 31, 2020 (in thousands): Balance at December 31, 2019 $ 4,720 Net loss (457 ) Balance at December 31, 2020 $ 4,263 Investments in Unconsolidated Real Estate Partnerships We own general and limited partner interests in partnerships that either directly, or through interests in other real estate partnerships, own apartment communities. We generally account for investments in real estate partnerships that we do not consolidate under the equity method. Accordingly, we recognize our share of the earnings or losses of the entity for the periods presented, inclusive of our share of any impairments and disposition gains or losses recognized by and related to such entities, and we present such amounts within income from unconsolidated real estate partnerships in our c onsolidated statements of operations. The excess of our cost of the acquired partnership interests over our share of the partners’ equity or deficit is generally ascribed to the fair values of land and buildings owned by the partnerships. We amortize the excess cost ascribed to the buildings over the related estimated useful lives. Such amortization is recorded as an adjustment of the amounts of earnings or losses we recognize from such unconsolidated real estate partnerships. We may also originate loans for real estate acquisitions or developments where we either expect, or have the opportunity, to participate in the residual profits from such projects. When the risks and rewards of these arrangements are similar to an equity investor or joint venture partner, we account for these arrangements as real estate investments using the equity method of accounting. We recognize as income changes in our share of net assets, adjusted for any basis differential, in mezzanine investment income, net, in our consolidated . We assess the recoverability of our equity method investments if there are indicators of potential impairment. We did not recognize any such impairments of our equity method investments during the years ended December 31, 2020, 2019, and 2018. Mezzanine Investment The Separation Agreement provides for AIR to transfer ownership of the subsidiaries that originated and hold the mezzanine loan to the partnership owning Parkmerced Apartments, the related equity option and the interest rate option, or swaption, that provides partial protection against future refinancing risk through 2024 once required consents to transfer are received. At the time of the Separation and as of March 12, 2021, AIR retained legal ownership of these subsidiaries. Until ownership of the subsidiaries is transferred, AIR is obligated to pass payments on such loan to us, and we are obligated to indemnify AIR against any costs and expenses related thereto. We have the risks and rewards of ownership of the Mezzanine Investment and have recognized an asset related to our right to receive the Mezzanine Investment from AIR. Prior to the Separation, consistent with the presentation of the consolidated financial statements on a carve out basis and considering intent to legally transfer the subsidiaries holding the mezzanine investment and related assets in connection with the Separation, the Mezzanine Investment was accounted for as an equity method investment. Accordingly, we recognized as income changes in our share of net assets, adjusted for any basis differential, in mezzanine investment income, net, in our consolidated statements of operations. Subsequent to the Separation, we recognize as income the net amounts recognized by AIR on its equity investment that are due to be paid to us when collected, which primarily represent the interest accrued under the terms of the underlying mezzanine loan. As of December 31, 2020, the Mezzanine Investment in our consolidated balance sheets represents the assets associated with our indirect interest in the subsidiary that owns Parkmerced Apartments, which we do not consolidate. Real Estate Acquisitions Upon the acquisition of real estate, we determine whether the purchase qualifies as an asset acquisition or, less frequently, meets the definition of an acquisition of a business. We generally recognize the acquisition of real estate or interests in partnerships that own real estate at our cost, including the related transaction costs, as asset acquisitions. We allocate the cost of real estate acquired based on the relative fair value of the assets acquired and liabilities assumed. The fair value of these assets and liabilities is determined using valuation techniques that rely on Level 2 and Level 3 inputs within the fair value framework. We determine the fair value of tangible assets, such as land, buildings, furniture, fixtures, and equipment using valuation techniques that consider comparable market transactions, replacement costs, and other available information. We determine the fair value of identified intangible assets or liabilities, which typically relate to in-place leases, using valuation techniques that consider the terms of the in-place leases, current market data for comparable leases, and our experience in leasing similar real estate. The intangible assets or liabilities related to in-place leases are comprised of: (a) the value of the above- and below-market leases in-place, measured over the period, including probable lease renewals for below-market leases, for which the leases are expected to remain in effect; (b) the estimated unamortized portion of avoided leasing commissions and other costs that Capital Additions We capitalize costs, including certain indirect costs, incurred in connection with our capital additions activities, including redevelopments, other tangible apartment community improvements, and replacements of existing community components. Included in these capitalized costs are payroll costs associated with time spent by employees in connection with the planning, execution, and control of all capital addition activities at our communities. We characterize as “indirect costs” an allocation of certain department costs, including payroll, at the area operations and corporate levels that clearly relate to capital addition activities. We also capitalize interest, property taxes, and insurance during periods in which construction projects are in progress. We commence capitalization of costs, including certain indirect costs, incurred in connection with our capital addition activities, at the point in time when activities necessary to get communities, apartment homes, or leased spaces ready for their intended use begin. These activities include when communities, apartment homes or leased spaces are undergoing physical construction, as well as when homes or leased spaces are held vacant in advance of planned construction, provided that other activities such as permitting, planning, and design are in progress. We cease the capitalization of costs when the communities or components thereof are substantially complete and ready for their intended use, which is typically when construction has been completed and homes or leased spaces are available for occupancy. We charge costs including ordinary repairs, maintenance, and resident turnover costs to property operating expense, as incurred . For the each of the years ended December 31, 2020, 2019, and 2018, we capitalized to buildings and improvements $1.0 million, $0.2 million, and $0.3 million of interest costs, respectively. For the years ended December 31, 2020, 2019, and 2018, we capitalized to buildings and improvements $2.7 million, $4.1 million, and $4.9 million of indirect costs, respectively. Gain or Loss on Dispositions Gain or loss on dispositions are recognized when we no longer hold a controlling financial interest in the real estate and sufficient consideration has been received. Upon disposition, the related assets and liabilities are derecognized, and the gain or loss on disposition is recognized as the difference between the carrying amount of those assets and liabilities and the value of consideration received. There were no dispositions in the years ended December 31, 2020, 2019, and 2018. Impairment Real estate and other long-lived assets to be held and used are stated at cost, less accumulated depreciation and amortization, unless the carrying amount of the asset is not recoverable. If events or circumstances indicate that the carrying amount of an asset may not be recoverable, we assess its recoverability by comparing the carrying amount to our estimate of the undiscounted future cash flows, excluding interest charges, of the community. If the carrying amount exceeds the aggregate undiscounted future cash flows, we recognize an impairment loss to the extent the carrying amount exceeds the estimated fair value of the community. In connection with the Separation, we entered into a sublease of office space within our corporate offices to AIR at then-current market rents. Based on an analysis of the estimated undiscounted cash flows relative to the sublease arrangement, we evaluated the recoverability of the assets associated with the subleased space, including, the right-of-use asset, tenant improvements and furniture, fixtures and equipment and concluded the subleased assets were impaired. We recorded an impairment charge of $11.0 million in our consolidated statements of operations for the year ended December 31, 2020. There were no such impairments for the years ended December 31, 2019 and 2018. In connection with the Separation, we entered into a software license agreement with AIR to provide for the use of certain internally developed software at then-current market rates. Based on an analysis of the estimated undiscounted cash flows relative to the carrying value of the internally developed software, we concluded the assets were impaired. Additionally, following an evaluation of the future service potential of certain other internal software that was under development, we ceased development and impaired the associated carrying value. We recorded an aggregate impairment charge of $4.9 million in our consolidated statements of operations for the year ended December 31, 2020. There were no such impairments for the years ended December 31, 2019 and 2018. Cash Equivalents We classify highly liquid investments with an original maturity of three months or less as cash equivalents. We maintain cash equivalents in financial institutions in excess of insured limits. We have not experienced any losses in these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions. Supplemental cash flow information for the years ended December 31, 2020, 2019 and 2018 is as follows: 2020 2019 2018 SUPPLEMENTAL CASH FLOW INFORMATION: Interest paid, net of amounts capitalized $ 22,152 $ 17,748 $ 19,296 Cash paid for income taxes 9,216 1,773 284 Non-cash transactions associated with the acquisition of real estate: Non-recourse property debt assumed in connection with the acquisition of real estate — 66,779 — Contributions from Aimco Predecessor 955 — — Contribution from noncontrolling interest in consolidated real estate partnerships 11,667 — — Deferred tax liability assumed in connection with the acquisition of real estate — 148,809 — Other non-cash transactions: Accrued capital expenditures (at end of period) 1,641 1,966 3,964 Non-recourse property debt assumed with collateral substitution — — 72,296 Issuance of Notes Payable to AIR in connection with the Separation 534,127 — — Contributions from Aimco Predecessor, net 131,447 — — Restricted Cash Restricted cash consists of tenant security deposits, capital replacement reserves, insurance reserves, and cash restricted as required by our debt agreements. O ther Assets As of December 31, 2020, and 2019, other assets were comprised of the following amounts (in thousands): 2020 2019 Intangible lease assets, net $ 7,264 $ 13,380 Accounts receivable, net of allowances of $1,467 and $80 as of December 31, 2020 and 2019, respectively 2,660 2,313 Prepaid expenses and real estate taxes 10,493 2,991 Investment in IQHQ 12,500 — Corporate fixed assets 12,860 — Deferred costs, deposits, and other 17,557 2,354 Total other assets, net $ 63,334 $ 21,038 Intangibles Intangible lease assets are included in other assets, net and intangible lease liabilities are included in accrued liabilities and other on the consolidated balance sheets. The following table details intangible lease assets and liabilities, net of accumulated amortization, for the years ended December 31, 2020, and 2019 (in thousands). 2020 2019 In-place leases and leasing costs $ 17,203 $ 16,355 Above-market leases 146 145 Less: accumulated amortization (10,085 ) (3,120 ) Intangible lease assets, net $ 7,264 $ 13,380 Below-market leases $ 4,886 $ 4,219 Less: accumulated amortization (2,366 ) (633 ) Intangible lease liabilities, net $ 2,520 $ 3,586 Based on the balance of intangible lease assets and liabilities as of December 31, 2020, the net aggregate amortization for the next five years and thereafter is expected to be as follows (in thousands). In-place leases and leasing costs Below-market leases 2021 $ 3,938 $ 1,201 2022 1,944 676 2023 830 321 2024 346 176 2025 206 146 Thereafter — — Total future amortization $ 7,264 $ 2,520 Accounts Receivable, net and Straight-line rent We present our accounts receivable and straight-line rent receivable net of allowances for amounts that may not be collected. The allowance is determined based on an assessment on whether substantially all of the amounts due from the resident or tenant is probable of collection. This includes a specific tenant analysis and aging analysis. Deferred Leasing Costs Beginning in 2019, in accordance with the adoption of Accounting Standard Codification (“ASC”) 842, we defer leasing costs incremental to a lease that we would not have incurred if the contract had not been obtained. Amortization of these costs is included in depreciation and amortization. Prior to 2019, we deferred leasing commissions and other direct costs incurred in connection with successful leasing efforts and amortized the costs over the terms of the related leases. Revenue from Leases We are a lessor for residential and commercial leases. Our operating leases with residents may provide that the resident reimburse us for certain costs, primarily the resident’s share of utilities expenses, incurred by the apartment community. Our operating leases with commercial tenants may provide that the tenant reimburse us for common area maintenance, real estate taxes, and other recoverable costs incurred by the commercial property. Beginning in 2019, with the adoption of ASC 842, we concluded that residential and commercial reimbursements represent revenue attributable to non-lease components for which the timing and pattern of recognition is the same as the revenue for the lease components. We adopted the practical expedient that allows us to account for the lease and non-lease components as a single component. Reimbursements and the related expenses are presented on a gross basis in our consolidated statements of operations, with the reimbursements included in rental and other property revenues in our consolidated statements of operations in the period the recoverable costs are incurred. We recognize rental revenue attributed to lease components, net of any concessions, on a straight-line basis over the term of the lease. Debt Issuance Costs We defer, as debt issuance costs, lender fees and other direct costs incurred in obtaining new financing and amortize the amounts over the terms of the related loan agreements. In connection with the modification of existing financing arrangements, we defer lender fees and amortize these costs and any unamortized debt issuance costs over the term of the modified loan agreement. Debt issuance costs associated with non-recourse property debt are presented as a direct deduction from the related liabilities in our consolidated balance sheets. For debt issuance costs associated with our revolving credit facilities and construction loans that have not been drawn we record the costs in other assets, net in our consolidated balance sheets and amortize the costs to interest expense, on a straight-line basis over the term of the arrangement. Debt issuance costs associated with construction loans are reclassified as a direct deduction to the construction loan liability in proportion to any draws on the loans in our consolidated balance sheets and subsequently amortized to interest expense on a straight-line basis over the remaining term of the arrangement in our consolidated statements of operations. When financing arrangements are repaid or otherwise extinguished prior to maturity, unamortized debt issuance costs are written off. Any lender fees or other costs incurred in connection with an extinguishment are recognized as expense. Amortization and write-off of debt issuance costs and other extinguishment costs are included in interest expense in our consolidated statements of operations. Depreciation and Amortization Depreciation for all tangible assets is calculated using the straight-line method over their estimated useful lives. Acquired buildings and improvements are depreciated over a useful life based on the age, condition, and other physical characteristics of the asset. Furniture, fixtures, and equipment are generally depreciated over five years. We depreciate capitalized costs using the straight-line method over the estimated useful life of the related improvement, which is generally 5, 15, or 30 years. We also capitalize payroll and other indirect costs incurred in connection with preparing an asset for its intended use. These costs include corporate-level costs that clearly relate to the capital addition activities, which we allocate to the applicable assets. All capitalized payroll costs and indirect costs are allocated to capital additions proportionately based on direct costs and depreciated over the estimated useful lives of such capital additions. Purchased equipment is recognized at cost and depreciated using the straight-line method over the estimated useful life of the asset, which is generally five years. Leasehold improvements are also recorded at cost and depreciated on a straight-line basis over the shorter of the asset’s estimated useful life or the term of the related lease. Certain homogeneous items that are purchased in bulk on a recurring basis, such as appliances, are depreciated using group methods that reflect the average estimated useful life of the items in each group. Except in the case of casualties, where the net book value of the lost asset is written off in the determination of casualty gains or losses, we generally do not recognize any loss in connection with the replacement of an existing community component because normal replacements are considered in determining the estimated useful lives used in connection with our composite and group depreciation methods. Income Taxes Aimco has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), commencing with its taxable year ended December 31, 1994, and it intends to continue to operate in such a manner. Our current and continuing qualification as a REIT depends on its ability to meet the various requirements imposed by the Internal Revenue Code, which are related to organizational structure, distribution levels, diversity of stock ownership and certain restrictions with regard to owned assets and categories of income. If Aimco qualifies for taxation as a REIT, it will generally not be subject to United States federal corporate income tax on our taxable income that is currently distributed to stockholders. This treatment substantially eliminates the “double taxation” (at the corporate and stockholder levels) that generally results from an investment in a corporation. Even if Aimco qualifies as a REIT, it may be subject to United States federal income and excise taxes in various situations, such as on undistributed income. Aimco also will be required to pay a 100% tax on any net income on non-arm’s length transactions between it and a TRS (described below) and on any net income from sales of apartment communities that were held for sale in the ordinary course. The state and local tax laws may not conform to the United States federal income tax treatment, and Aimco may be subject to state or local taxation in various state or local jurisdictions, including those in which we transact business. Any taxes imposed on us reduce our operating cash flow and net income. Certain of Aimco’s operations or a portion thereof, including property management and risk management, are conducted through taxable REIT subsidiaries, which are our subsidiaries of the Aimco Operating Partnership, and each of which we refer to as a TRS. A TRS is a subsidiary C-corporation that has not elected REIT status and, as such, is subject to United States federal corporate income tax. We use TRS entities to facilitate our ability to offer certain services and activities to our residents and investment partners that cannot be offered directly by a REIT. We also use TRS entities to hold investments in certain apartment communities. For our TRS entities, deferred income taxes result from temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for United States federal income tax purposes, and are measured using the enacted tax rates and laws that are expected to be in effect when the differences reverse. We reduce deferred tax assets by recording a valuation allowance when we determine, based on available evidence, that it is more likely than not that the assets will not be realized. We recognize the tax consequences associated with intercompany transfers between the A imco Operating Partnership and TRS entities when such transactions occur. Please refer to Note 9 for further information about our income taxes. Earnings per Share and per Unit We and the Aimco Operating Partnership calculate earnings per share and unit based on the weighted-average number of shares of common stock or common OP units, participating securities, common stock or common unit equivalents and dilutive convertible securities outstanding during the period. The Aimco Operating Partnership considers both common OP units and equivalents, which have identical rights to distributions and undistributed earnings, to be common units for purposes of the earnings per unit computations. Please refer to Note 12 for further information regarding earnings per share and unit computations. Use of Estimates The preparation of our consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts included in the consolidated financial statements and accompanying notes thereto. Actual results could differ from those estimates. Accounting Pronouncements Adopted in the Current Year Effective January 1, 2020, we adopted ASC 326, Financial Instruments-Credit Losses, Recent Accounting Pronouncements On January 2020, the FASB issued Accounting Standard Update (“ASU”) 2020-01, Investment – Equity Securities Investments – Equity Method and Joint Venture Derivatives and Hedging On August 2020, the FASB issued ASU 2020-06, Debt - Debt with Conversion and Other Options Derivatives and Hedging – Contracts in Entity’s Own Equity

Significant Transactions

Significant Transactions	12 Months Ended
	Dec. 31, 2020
Significant Transactions [Abstract]
Significant Transactions	Note 3 — Significant Transactions Acquisition of Upton Place On December 4, 2020, we entered into a joint venture partnership with AIR (the “Upton Place Holding JV”) to acquire a 90% interest in a joint venture partnership (the “Upton Place JV”) with a third party developer (“Developer”). The Upton Place JV was formed to acquire Upton Place, a mixed-use development project which will create 689 apartment homes and approximately 100,000 square feet of commercial space in upper-northwest Washington, D.C. Upton Place Holding JV We issued an $85.0 million promissory note (representing a commitment to fund equity) for an approximate 81% interest and AIR contributed $20.0 million for an approximate 19% interest in the Upton Place Holding JV. As of December 31, 2020, $5.2 million of the $85 million was funded. Following the formation of the Upton Place Holding JV, contemporaneous with the Separation, Aimco and AIR also entered into a membership interest lease agreement in which AIR assigned all its economic rights in the Upton Place Holding JV to Aimco in exchange for annual payments of $1.15 million. We evaluated the joint venture, concluded that we are the primary beneficiary and therefore consolidate the Upton Place Holding JV . AIR’s equity interest in the joint venture is presented as noncontrolling interest s in consolidated real estate partnerships in the consolidated balance sheets. Upton Place JV Contemporaneous with the formation of the joint venture, the Developer provided a guaranty of cost overruns which requires the Developer to fund all costs and expenses in excess of certain guaranteed cost amounts. The Developer has also guaranteed the project’s construction, delivery and will be responsible for managing the lease up and management of the retail units. We will be responsible for the lease-up and management of the residential units. The Developer has a 10% interest in the Upton Place JV as well as rights to receive a promote distribution contingent on certain internal rates of return. Upon final completion of the project and following 360 days after stabilization (“Stabilization”, defined as at least 95% of apartment units and 90% of retail space being leased with tenants having taken possession), the Developer has the option to require the Upton Place JV to redeem its promote based on the then fair value of the project. We evaluated the joint venture, concluded that we are the primary beneficiary and therefore consolidate the Upton Place JV. The Developer’s equity interest in the joint venture is presented as noncontrolling interests in consolidated real estate partnerships in the consolidated balance sheets. The Developer’s contingent option relative to its promote distribution is a liability. As of December 31, 2020, the Developer’s noncontrolling interest and promote distribution liability was $11.7 million and $0, respectively. In conjunction with the acquisition of Upton Place, we entered into two 99-year ground leases with a third party for the land underlying the property. Upon the signing of the Upton Place JV we paid customary acquisition costs including a broker fee to a related party in the amount of $1.8 million. Acquisition of Hamilton on the Bay On August 25, 2020, we acquired Hamilton on the Bay, an apartment community and an adjacent land parcel located in Miami, Florida. Summarized information regarding these acquisitions is set forth in the table below (in thousands): Purchase price 115,394 Capitalized transaction costs 5,136 Total consideration $ 120,530 Land 56,649 Building and improvements 56,171 Right-of-use lease assets 92,787 Due from affiliates 705 Lease liabilities (86,348 ) Intangible assets (1) 1,517 Below-market lease liabilities (2) (951 ) Total consideration $ 120,530 ( 1) Intangible assets include in-place leases and leasing costs with a weighted-average term of 0.5 years. (2) Below-market leases have a weighted-average term of 0.6 years. Life Science Developer Investment As of December 31, 2020, we have a $12.5 million investment in and a $37.5 million commitment to IQHQ, a privately-held life-sciences real estate development company. In addition, Aimco has the right to collaborate with IQHQ on any multifamily component at its future development sites.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Note 4 — Leases Lessor Arrangements The majority of payments we receive for our residential and commercial leases are fixed. We receive variable payments from our residents and commercial tenants primarily for utility reimbursements and other services. We determine if an arrangement is or a lease at inception. Our total lease income was comprised of the following amounts for all operating leases for the year ended December 31, 2020 (in thousands): 2020 2019 Fixed lease income $ 140,140 $ 133,180 Variable lease income 11,192 9,929 Total lease income $ 151,332 $ 143,109 In general, our commercial leases have options to extend for a certain period of time at the tenant’s option. Future minimum annual rental payments we will receive under commercial leases, excluding such extension options, are as follows as of December 31, 2020 (in thousands): 2021 $ 10,866 2022 9,047 2023 5,761 2024 3,664 2025 2,551 Thereafter 1,315 Total $ 33,204 Generally, our residential leases do not provide extension options so the average remaining term is less than one year. Our commercial leases, as of December 31, 2020, have an average remaining term of 2.8 years. Lessee Arrangements We estimated the value of our lease liabilities using discount rates equivalent to the rates we would pay on a secured borrowing with terms similar to the leases. We determine if an arrangement is or contains a lease at inception. We have lease agreements with lease and non-lease components and have elected to not separate these components for all classes of underlying assets. Leases with an initial term of 12 months or less are not recorded on the consolidated balance sheet. Leases with initial terms greater than 12 months are recorded as operating or financing leases on the consolidated balance sheets. During the year ended December 31, 2020, we entered into two 99-year ground leases for the land underlying the development site at Upton Place and initially recorded right-of-use lease assets and lease liabilities of $92.8 million and $86.3 million, respectively. We also have a lease for our corporate office. Substantially, all of the payments under our ground and office leases are fixed. We exclude o ptions to extend the leases in our minimum lease terms unless the options are reasonably certain to be exercised. As of December 31, 2020, the ground and office leases have weighted-average remaining terms of 99 years and 8.4 years, respectively, and weighted-average discount rates of 6.0% and 3.2%, respectively. Minimum annual rental payments under these operating and financing leases, reconciled to the lease liabilities in our consolidated balance sheets, are as follows (in thousands): Sublease Income Operating Lease Future Minimum Rent Financing Leases Future Minimum Payments 2021 $ 1,380 $ 1,472 $ 1,200 2022 1,393 1,841 1,600 2023 1,403 1,871 2,000 2024 1,413 1,900 3,000 2025 1,423 1,930 3,500 Thereafter 4,959 6,814 1,151,782 Total $ 11,971 $ 15,828 $ 1,163,082 Less: Discount (2,113 ) (1,076,301 ) Total lease liabilities $ 13,715 $ 86,781

Transactions with AIR

Transactions with AIR	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Transactions with AIR	Note 5 — Transactions with AIR After the Separation, we and AIR are operating as two, focused and independent companies. We entered into various separation and transition services agreements with AIR that provide for a framework of our relationship with AIR after the Separation, including: (i) a separation agreement setting forth the mechanics of the Separation, the key provisions relating to the separation of our assets and liabilities from those of AIR, and certain organizational matters and conditions; (ii) an employee matters agreement to allocate liabilities and responsibilities relating to employment matters, employee compensation, and benefits plans and programs, and other related matters; (iii) agreements pursuant to which AIR will provide property management and related services to us (collectively, the “Property Management Agreements”); (iv) an agreement pursuant to which AIR will provide us with customary administrative and support services on an ongoing basis (the “Master Services Agreement”); and (v) a Master Leasing Agreement where we may enter into leases with AIR with the option to redevelop, develop, or lease-up, and under which we will have certain lease termination rights (the “Master Leasing Agreement”). Property Management Agreements We entered into several Property Management Agreements with AIR, pursuant to which AIR will provide us with certain property management/property accounting and related services for the majority of our operating properties, and we will pay AIR a property management fee of 3% of each respective property’s revenue collected and such other fees as may be mutually agreed for various other services. The initial term of each property management/property accounting agreement is one-year, with automatic one-year renewal periods, unless either party elects to terminate at any time upon delivery of 60 days’ prior written notice to the other party. Neither party is obligated to pay to the other party a termination fee or other penalty upon such termination. Subsequent to the Separation, we recorded property management/property accounting fees of $0.2 million, which is included in property operating expenses in our consolidated statements of operations. Master Services Agreement We and AIR entered into a Master Services Agreement, in which AIR will provide us with customary administrative and support services. We are obligated to pay AIR the fully burdened costs (including internal allocated costs) in performing the services. We may terminate any or all services on 60 days’ prior written notice, and AIR may terminate individual services, at any time after December 31, 2023. Master Leasing Agreement The Master Leasing Agreement governs the current and any future leasing arrangements between us, as lessee and AIR, as lessor; the initial term of the Master Leasing Agreement is 18 months, with automatic annual extensions (subject to each party’s right to terminate upon notice prior to the end of any such extension term). The Master Leasing Agreement provides that each time the parties thereto wish to execute a lease for a particular property, such parties will cause their applicable affiliates to execute a stand-alone lease (each, a “Lease”.) The initial annual rent for any leased property is based on the then-current fair market value of the subject property and market NOI cap rates, subject to certain adjustments, and is further subject to periodic escalation as set forth in the applicable Lease, and the other terms thereof, including the initial term and extensions. We have the right to terminate any such Lease prior to the end of its term once the leased property is stabilized. In connection with such an early termination, AIR will generally have an option (and not an obligation) to pay us an amount equal to the difference between the then-current fair market value of such property and the initial fair market value of such property at the time of Lease inception, at a five percent discount thereto; if AIR does not exercise such option, we will have the right to cause such property to be sold to a third party, with AIR guaranteed to receive an amount equal to the fair market value of the property at the time of the Lease inception and we will retain any excess proceeds. In the event of such sale of the property, we may also elect to purchase the property at a purchase price equal to the fair market value as agreed upon at the time of Lease inception (and may subsequently sell the property to a third party, subject to AIR’s right of first refusal during the first year following our acquisition). If AIR elects not to pay the fee for the development or redevelopment-related improvements, and we decline to purchase the property or cause its sale to a third party, we may elect to rescind its termination of the applicable lease and instead continue such lease in effect in accordance with its terms. See Note—17 for further details related to properties leased on January 1, 2021. Notes Payable to AIR On December 14, 2020, we entered into $534.1 million of Notes Payable to AIR that are secured by a pledge of the equity interest in the entity that holds a portfolio of assets, however, the assets secure existing senior loans of $215.4 million as of December 31, 2020. The notes will mature on January 31, 2024 and bear interest at 5.2%, with accrued interest payable quarterly on January 1, April 1, July 1 and October 1, and commencing on April 1, 2021. For the year ended December 31, 2020, we recognized interest expense of $1.3 million associated with the Notes Payable to AIR. See Note—8 for further details. Expense Allocation In preparing our consolidated financial statements for the periods prior to the Separation, certain expenses, including property operating expenses, depreciation and amortization, and general and administrative expenses, incurred at the corporate level that are attributable to us have been allocated on a carve-out basis. Expenses allocated for the years ended December 31, 2020, 2019, and 2018, were $9.8 million, $9.5 million, and $7.6 million, respectively. Depending on the nature of the expense, the allocation was based on Aimco’s relative share of total gross potential revenue and the relative gross asset value of our communities as compared to the total gross potential revenue and gross asset value of all communities held by Aimco Predecessor, which we believe to be reasonable methodologies. These allocated expenses are centralized corporate costs for management and other services, including, but not limited to, executive oversight, treasury, finance, human resources, tax, accounting, financial reporting, information technology, and investor relations. Sublease with AIR In December 2020, we entered into a sublease arrangement with AIR to provide space within our corporate office, including tenant improvements and furniture, fixtures and equipment, at then-current market rents. The sublease provides for fixed rents, which commenced on January 1, 2021 and expire on May 31, 2029. Please refer to Note 4 for further information about our sublease income. As of December 31, 2020, we have amounts due to and due from AIR of $5.9 million and $3.6 million, respectively. The due to AIR primarily consist of invoices paid on our behalf and accrued interest on the Notes Payable to AIR. The due from AIR primarily consist of prepaid rents. Guarantee Liability Legal liabilities that relate to occurrences prior to the Separation, including environmental liabilities related to properties that were no longer owned by Aimco or AIR at the time of the Separation, pursuant to the terms of the Separation Agreement, Aimco Operating Partnership will bear the first $17.5 million of such liabilities, in the aggregate, and AIR Operating Partnership will bear any such liabilities in excess of $17.5 million. On the date of Separation, we recognized a guarantee liability of $16.4 million based on an estimate of the expected future cash flows required to settle the legal liabilities, including, but not limited to, remediation, settlement and legal costs, discounted by an estimated market discount rate of 4.25%. The guarantee liability will be systematically reduced in proportion to the estimated liability as costs related to the legal liabilities are incurred, which we estimate will occur through 2023. As of December 31, 2020, the guarantee liability of $ 16.3 million is included in accrued liabilities and other in our consolidated balance sheets.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Variable Interest Entities	Note 6 — Variable Interest Entities Generally, a VIE is a legal entity in which the equity investors do not have the characteristics of a controlling financial interest or the equity investors lack sufficient equity at risk for the entity to finance its activities without additional financial support. A limited partnership is considered a VIE when the majority of the limited partners unrelated to the general partner possess neither the right to remove the general partner without cause, nor certain rights to participate in the decisions that most significantly affect the financial results of the partnership. 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 our business activities and the business activities of 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. The VIEs we consolidate own interests in real estate. We are the primary beneficiary for the VIEs because we have the power to direct the activities that most significantly impact the entities’ economic performance and have a substantial economic interest. We have six unconsolidated VIEs for which we are not the primary beneficiary because we are not the decision maker. The details of our consolidated and unconsolidated VIEs are summarized in the table below as of December 31, 2020 and 2019 (in thousands, except for VIE count). December 31, 2020 December 31, 2019 Consolidated Unconsolidated Consolidated Unconsolidated Count of VIEs 2 6 1 5 Assets: Real estate, net $ 310,552 $ — $ 299,387 $ — Mezzanine investment — 307,362 — 280,258 Right-of-use lease assets 92,709 — — — Unconsolidated real estate partnerships — 12,829 — 12,741 Other assets 16,949 12,500 14,645 — Liabilities: Notes Payable to AIR — — 66,295 — Deferred tax liability 133,842 — 143,934 — Accrued liabilities and other 7,106 — 8,873 — Lease liabilities 86,781 — — — Assets of our consolidated VIEs must first be used to settle the liabilities of the VIE. The consolidated VIEs’ creditors do not have recourse to our general credit. Unconsolidated Real Estate Partnerships We own an interest in four apartment communities in San Diego, California, of which we are not the primary beneficiary. Our investment balance of $12.8 million and $12.7 million as of December 31, 2020 and 2019, respectively, represents our maximum exposure to loss in these VIEs. Our other unconsolidated VIE is insignificant to our consolidated balance sheets for both periods presented. As discussed in Note 2, AIR owns an interest in a partnership that owns Parkmerced Apartments, of which it is not the primary beneficiary, and under the terms of the Separation Agreement, AIR is obligated to transfer ownership of the subsidiaries that hold this interest to us upon receipt of applicable third-party consent. Our investment balance of $307.4 million as of December 31, 2020, reflected in Mezzanine Investment in our consolidated balance sheets, represents our indirect interest in notes receivable through our agreement with AIR and represents our maximum exposure to loss in this VIE. Please refer to Note 7 for further details.

Mezzanine Investment

Mezzanine Investment	12 Months Ended
	Dec. 31, 2020
Equity Method Investments And Joint Ventures [Abstract]
Mezzanine Investment	Note 7 – Mezzanine Investment The Mezzanine Investment, accounted for as an equity method investment prior to Separation, is significant as defined by the Securities and Exchange Commission. Accordingly, we have included the audited financial statements of Parkmerced Apartments for the year ended December 31, 2020. The following table provides summarized balance sheet information of the Parkmerced Apartments as of December 31, 2019 (in thousands): December 31, 2019 Assets: Real estate, net $ 580,242 Cash and cash equivalents 25,078 Restricted cash 917 Other assets 22,510 Liabilities and equity: Notes payable, net 1,545,587 Other liabilities 15,149 Deficit $ (931,989 ) The following table provides a summarized statement of operations information of the Parkmerced Apartments from the date of our investment, November 26, 2019, through December 31, 2019 (in thousands): REVENUES: Rental and other property revenues $ 10,089 OPERATING EXPENSES: Property operating expenses 4,365 Depreciation and amortization 2,116 General and administrative expenses 1,250 Total operating expenses 7,731 Interest expense (9,657 ) Other income, net 2,920 Net loss $ (4,379 ) The following table provides a summarized statement of cash flow information of the Parkmerced Apartments from the date of our investment, November 26, 2019, through December 31, 2019 (in thousands): CASH FLOWS FROM OPERATING ACTIVITIES: Net cash used in operating activities $ (12,869 ) CASH FLOWS FROM INVESTING ACTIVITIES: Purchases of improvements, furniture, fixtures, and equipment (986 ) Net cash used in investing activities $ (986 ) CASH FLOWS FROM FINANCING ACTIVITIES: Proceeds from mortgage note payable 1,500,000 Proceeds from mezzanine note payable 275,000 Payments of mortgage financing costs (146,250 ) Payment of interest rate swap (15,900 ) Repayment of mortgage note payable (450,000 ) Repayment of mezzanine notes payable (1,047,927 ) Distributions (98,777 ) Net cash provided by investing activities $ 16,146 NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH 2,291 CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD 23,704 CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT END OF PERIOD $ 25,995

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Note 8 —Debt Revolving Credit Facility On December 16, 2020, we entered into a credit agreement with PNC Bank. The credit agreement provides for a new $150.0 million secured credit facility, a $20.0 million swingline loan sub-facility and a $30.0 million letter of credit sub-facility. We can request incremental commitments under the credit agreement up to an aggregate principal amount of $300.0 million. The credit facility expires on December 2023 As of December 31, 2020, we had no outstanding balance related to the credit facility, the swingline sub-facility or the letter of credit Sub-facility. Total debt issuance costs of approximately $1.9 million have been deferred and are presented within other assets, net in our consolidated balance sheets. Under our revolving secured credit facility, we are required to maintain a fixed charge coverage ratio of 1.25x, minimum adjusted tangible net worth of $625.0 million, and maximum leverage of 60% as defined in the credit agreement, among other customary covenants. We are currently in compliance with these covenants. Notes Payable to AIR On December 14, 2020, our subsidiary, Aimco JO Intermediate Holdings LLC (“Aimco JO”) entered into two notes aggregating to $534.1 million (the “Notes Payable to AIR” or “Notes”) in exchange for an equity interest in James-Oxford Limited Partnership (“James Oxford”) a consolidated subsidiary of Aimco that indirectly owns a portfolio of consolidated real estate assets. The Notes are secured by a pledge of the equity interests in James Oxford, however, James Oxford’s assets secure existing senior loans of $215.4 million as of December 31, 2020. The Notes mature on January 31, 2024 and bear interest at 5.2%, with accrued interest payable quarterly on January 1, April 1, July 1 and October 1, commencing on April 1, 2021. For the year ended December 31, 2020, we recognized interest expense of $1.3 million associated with the Notes Payable to AIR, which is included in interest expense and due to affiliates on the consolidated statements of operations and consolidated balance sheets, respectively. Upon a disposition, consolidation, or similar event or transaction, Aimco JO is obligated to prepay the Notes in an amount equal to the net cash proceeds received in connection with such transaction or casualty event. Any such prepayment shall be accompanied by accrued and unpaid interest and a make-whole amount representing all remaining unpaid interest over the term of the Notes. However, if after giving effect to such transaction or casualty event, the fair market value of all real estate assets owned by James Oxford and its subsidiaries, less senior secured indebtedness (e.g., nonrecourse property debt), exceeds the then-outstanding principal balance of the Notes, we have the option to reinvest the net cash proceeds within 180 days of such transaction or casualty event by acquiring, leasing, constructing, or improving real property useful in the business of Aimco JO or its subsidiaries that we believe in good faith will enhance or create value. We are not otherwise permitted to prepay the Notes prior to the maturity date. The Notes Payable to AIR are senior secured obligations of Aimco JO and rank senior to all other senior obligations of Aimco JO to the extent of the value of the underlying collateral and rank pari passu with all other senior unsubordinated obligations of Aimco JO to the extent the amount of such obligations exceed the value of the underlying collateral. The Notes are not guaranteed and as a result, recourse is limited to Aimco JO, its assets and the underlying collateral pledged to secure Aimco JO’s obligations under the Notes. The Notes also contain customary representations, warranties, non-financial covenants and events of default. Upton Construction Loan On December 23, 2020, our Upton Place joint venture entered into a construction loan with Bank OZK for up to $174.2 million, which was undrawn at December 31, 2020. The construction loan is secured by the 99-year leasehold interest in the development site and by improvements to be constructed on the development site. Interest will accrue on the construction loan only when the funds are drawn upon. Funds drawn upon will bear interest at a rate equal to one month Libor (“Libor”) plus 450 basis points subject to a minimum all-in per annum interest rate of 4.75%. The initial term of the construction loan is fifty-four months, beginning December 23, 2020. The Upton Place joint venture has the option to extend the term for two additional periods of one year each, subject to the satisfaction of certain events and covenant metrics. Total debt issuance costs of approximately $7.5 million have been deferred and are presented within other assets, net in our consolidated balance sheets. Property-Level Debt We finance apartment communities in our portfolio primarily using property-level, non-recourse, long-dated, fixed-rate, amortizing debt. The following table summarizes non-recourse property debt a s of December 31, 2020 and 2019 (in thousands): Outstanding Balance as of December 31, Latest Maturity Date Interest Rate Range Weighted-Average Interest Rate 2020 2019 Fixed-rate property debt November 22, 2032 1.00% to 4.08% 3.38% $ 394,510 $ 438,886 Variable-rate property debt December 31, 2023 1.34% 1.34% 55,000 55,000 Total non-recourse property debt $ 449,510 $ 493,886 Assumed debt fair value adjustment, net of accumulated amortization 1,850 2,153 Debt issuance costs, net of accumulated amortization (3,393 ) (3,401 ) Non-recourse property debt, net $ 447,967 $ 492,638 Principal and interest on our non-recourse property debt are generally payable monthly. As of December 31, 2020, our property debt was secured by 11 apartment communities. These debt instruments contain no financial covenants. As of December 31, 2020, the scheduled principal amortization and maturity payments for the non-recourse property debt were as follows (in thousands): Amortization Maturities Total 2021 $ 8,648 $ — $ 8,648 2022 9,087 15,773 24,860 2023 9,144 55,000 64,144 2024 7,099 81,940 89,039 2025 7,361 — 7,361 Thereafter 17,363 238,095 255,458 Total $ 58,702 $ 390,808 $ 449,510

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Note 9 — Income Taxes Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities of our taxable entities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax liabilities and assets are as follows (in thousands): December 31, 2020 2019 Deferred tax liabilities: Real estate and real estate partnership basis differences $ 132,599 $ 148,842 Deferred tax assets: Management contracts and other 999 615 Net operating, capital, and other loss carryforwards 40 — Net deferred tax liability $ 131,560 $ 148,227 During the year ended December 31, 2019, we recognized a $148.8 million deferred tax liability in connection with the acquisition of 1001 Brickell Bay Drive. Our policy is to include any interest and penalties related to income taxes within income tax benefit (expense) in our consolidated statements of operations. Significant components of the income tax benefit (expense) are as follows and are classified within income tax benefit (expense) in our consolidated statements of operations for the years ended December 31, 2020, 2019, and 2018 (in thousands): 2020 2019 2018 Current: Federal $ 857 $ 1,313 $ — State 660 536 284 Total current 1,517 1,849 284 Deferred: Federal (10,470 ) (4,658 ) 16 State (1,196 ) (492 ) (39 ) Total deferred (11,666 ) (5,150 ) (23 ) Total income tax (benefit) expense $ (10,149 ) $ (3,301 ) $ 261 Consolidated income or loss subject to tax consists of pretax income or loss of our taxable entities and income and gains retained by the REIT. For the years ended December 31, 2020, 2019, and 2018, we had consolidated net loss subject to tax of $25.5 million, consolidated net loss subject to tax of $7.5 million, and consolidated net income subject to tax of $0.1 million, respectively. The reconciliation of income tax attributable to operations computed at the United States statutory rate to income tax benefit (expense) for the years ended December 31, 2020, 2019, and 2018 is shown below (in thousands): 2020 2019 2018 Amount Percent Amount Percent Amount Percent Tax (benefit) expense at United States statutory rates on consolidated income or loss subject to tax $ (5,361 ) 21.0 % $ (1,582 ) 21.0 % $ 16 21.0 % US branch profits tax on earnings of foreign subsidiary (4,195 ) 16.4 % (1,779 ) 23.6 % — — State income tax, net of federal (benefit) expense (536 ) 2.1 % 34 (0.5 %) 245 326.6 % Effects of permanent differences 1 (0.0 %) — — — — Other (58 ) 0.2 % 26 (0.3 %) — — Total income tax (benefit) expense $ (10,149 ) 39.7 % $ (3,301 ) 43.8 % $ 261 347.6 % Income taxes paid totaled approximately $9.2 million, $1.8 million, and $0.3 million for the years ended December 31, 2020, 2019, and 2018, respectively. For income tax purposes, dividends paid to holders of Common Stock primarily consist of ordinary income, capital gains, qualified dividends and unrecaptured Section 1250 gains, or a combination thereof. For the years ended December 31, 2020, 2019 and 2018, tax attributes of dividends per share held for the entire year were estimated to be as follows (unaudited): 2020 2019 2018 Amount Percent Amount Percent Amount Percent Ordinary income $ 3.17 6.7 % $ 0.66 20.6 % $ 0.51 33.5 % Capital gains 19.43 40.9 % 1.29 40.4 % 0.93 61.2 % Qualified dividends 0.62 1.3 % 0.66 20.7 % — 0 % Unrecaptured § 1250 gain 8.80 18.5 % 0.58 18.3 % 0.08 5.4 % Return of capital 15.48 32.6 % — — — — Balance at December 31 $ 47.50 100 % $ 3.19 100 % $ 1.52 100 % A reconciliation of the beginning and ending balance of our unrecognized tax benefits is presented below and is included in accrued liabilities and other in the consolidated balance sheets (in thousands): December 31, 2020 2019 Balance at January 1 $ — $ — Liability assumed at Separation 6,889 — Additions based on tax positions in prior years 187 — Balance at December 31 $ 7,076 $ — Because the statute of limitations has not yet elapsed, our United States federal income tax returns for the year ended December 31, 2017, and subsequent years and certain of our State income tax returns for the year ended December 31, 2017, and subsequent years are currently subject to examination by the IRS or other taxing authorities. If recognized, the unrecognized benefit would affect the effective rate. In accordance with the accounting requirements for stock-based compensation, we may recognize tax benefits in connection with the exercise of stock options by employees of our TRS entities and the vesting of restricted stock awards. We recognize the tax effects related to stock-based compensation through earnings in the period the compensation is recognized.

Aimco Equity

Aimco Equity	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Aimco Equity	Note 10 — Aimco Equity On December 15, 2020, we completed the previously announced separation of our business into two, separate and distinct, publicly traded companies, Aimco and AIR. The Separation was effected by way of a pro rata distribution, in which stockholders of Aimco received one share of Class A common stock of AIR for every one share of Class A common stock of Aimco held as of the close of business on December 5, 2020. AIR Operating Partnership also completed a pro rata distribution of all of the outstanding common limited partnership units of Aimco Operating Partnership to holders of AIR Operating Partnership common limited partnership units and AIR Operating Partnership Class I High Performance partnership units as of the close of business on December 5, 2020. Notwithstanding the legal form of the Separation, for accounting and financial reporting purposes, Aimco is presented as being spun-off from AIR. Therefore, we are the accounting spinee and AIR is considered the divesting entity and treated as the accounting spinnor, or accounting predecessor. Since the assets, liabilities and operations of Aimco prior to the Separation were spread across multiple legal entities, a separate capital structure did not exist. Immediately following the Separation, our Board of Directors was authorized to issue up to 510,587,500 shares of common stock.

Partners' Capital

Partners' Capital	12 Months Ended
	Dec. 31, 2020
Partners Capital [Abstract]
Partners' Capital	Note 11 — Partners’ Capital Separation from AIR On December 15, 2020, Aimco Operating Partnership completed the Separation, which was effected, in part, through a pro rata distribution of all of the outstanding common limited partnership units of Aimco Operating Partnership to holders of AIR Operating Partnership common limited partnership units and AIR Operating Partnership Class I High Performance partnership units as of the close of business on December 5, 2020. In addition, stockholders of Aimco received one share of Class A common stock of AIR for every one share of Class A common stock of Aimco held as of the close of business on the record date, and received cash in lieu of fractional shares of Class A common stock of AIR. Aimco Operating Partnership Partners’ Capital Common Partnership Units In the Aimco Operating Partnership’s consolidated balance sheets, the common partnership units held by Aimco are classified within Partners’ Capital as General Partner and Special Limited Partner capital and the common OP Units are classified within Limited Partners’ capital. In Aimco’s consolidated balance sheets, the common OP Units are classified within permanent equity as common noncontrolling interests in Aimco Operating Partnership. Common partnership units held by Aimco are not redeemable whereas common OP Units are redeemable at the holders’ option, subject to certain restrictions, on the basis of one common OP Unit for either one share of Common Stock or cash equal to the fair value of a share of Common Stock at the time of redemption. Aimco has the option to deliver shares of Common Stock in exchange for all or any portion of the common OP Units tendered for redemption. When a limited partner redeems a common OP Unit for Common Stock, Limited Partners’ capital is reduced, and the General Partner and Special Limited Partners’ capital is increased. The holders of the common OP Units receive distributions in an amount equivalent to the dividends paid to holders of Common Stock.

Earnings per Share and per Unit

Earnings per Share and per Unit	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings per Share and per Unit	Note 12 — Earnings per Share and per Unit Aimco and the Aimco Operating Partnership calculate basic earnings per common share and basic earnings per common unit based on the weighted-average number of shares of Common Stock and common partnership units outstanding. We calculate diluted earnings per share and diluted earnings per unit taking into consideration dilutive common stock and common partnership unit equivalents and dilutive convertible securities outstanding during the period. The common shares and common partnership units outstanding at the Separation date are reflected as outstanding for all periods prior to the Separation for purposes of determining earnings per share and per unit. Our Common Stock and common partnership unit equivalents include options to purchase shares of Common Stock, which, if exercised, would result in Aimco’s issuance of additional shares and the Aimco Operating Partnership’s issuance to Aimco of additional common partnership units equal to the number of shares purchased under the options. These equivalents also include unvested TSR Restricted Stock awards that do not meet the definition of participating securities, which would result in an increase in the number of shares of Common Stock and common partnership units outstanding equal to the number of the shares that vest. Common partnership unit equivalents also include unvested long-term incentive partnership units. We include in the denominator securities with dilutive effect in calculating diluted earnings per share and per unit during these periods. Our Time-Based Restricted Stock awards receive non-forfeitable dividends similar to shares of Common Stock and common partnership units prior to vesting, and our TSR LTIP I units and TSR LTIP II units receive non-forfeitable distributions based on specified percentages of the distributions paid to common partnership units prior to vesting and conversion. The unvested restricted shares and units related to these awards are participating securities. We include the effect of participating securities in basic and diluted earnings per share and unit computations using the two-class method of allocating distributed and undistributed earnings when the two-class method is more dilutive than the treasury stock method. Reconciliations of the numerator and denominator in the calculations of basic and diluted earnings per share and per unit for the years ended December 31, 2020, 2019, and 2018 are as follows (in thousands, except per share and per unit data): Year Ended December 31, 2020 Income (Numerator) Shares (Denominator) Per Share Amount Basic and Diluted Earnings per Share: Net loss attributable to Aimco common stockholders $ (5,041 ) 148,569 $ (0.03 ) Year Ended December 31, 2019 Income (Numerator) Shares (Denominator) Per Share Amount Basic and Diluted Earnings per Share: Net income attributable to Aimco common stockholders $ 304 148,549 $ — Diluted Earnings per Share: Effect of dilutive securities — 20 — Net income attributable to Aimco common stockholders $ 304 148,569 $ — Year Ended December 31, 2018 Income (Numerator) Shares (Denominator) Per Share Amount Basic and Diluted Earnings per Share: Net income attributable to Aimco common stockholders $ 3,243 148,549 $ 0.02 Diluted Earnings per Share: Effect of dilutive securities — 20 — Net income attributable to Aimco common stockholders $ 3,243 148,569 $ 0.02 Year Ended December 31, 2020 Income (Numerator) Shares (Denominator) Per Unit Amount Basic and Diluted Earnings per unit: Net loss attributable to Aimco Operating Partnership's common unitholders $ (5,310 ) 156,500 $ (0.03 ) Year Ended December 31, 2019 Income (Numerator) Shares (Denominator) Per Unit Amount Basic and Diluted Earnings per unit: Net income attributable to Aimco Operating Partnership's common unitholders $ 319 156,480 $ — Diluted Earnings per unit: Effect of dilutive securities — 20 — Net income attributable to Aimco Operating Partnership's common unitholders $ 319 156,500 $ — Year Ended December 31, 2018 Income (Numerator) Shares (Denominator) Per Unit Amount Basic and Diluted Earnings per unit: Net income attributable to Aimco Operating Partnership's common unitholders $ 3,416 156,480 $ 0.02 Diluted Earnings per unit: Effect of dilutive securities — 20 — Net income attributable to Aimco Operating Partnership's common unitholders $ 3,416 156,500 $ 0.02

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	Note 13 — Share-Based Compensation We have a stock award and incentive program to attract and retain officers and independent directors. As of December 31, 2020, approximately 29.8 million shares were available for issuance under the Second Amended and Restated 2015 Stock Award and Incentive Plan (the “2015 Plan”). The total number of shares available for issuance under this plan may increase due to any forfeiture, cancellation, exchange, surrender, termination or expiration of an award outstanding under the 2015 Plan. Awards under the 2015 Plan may be in the form of incentive stock options, non-qualified stock options, or other types of awards as authorized under the Plan. Our plans are administered by the Compensation and Human Resources Committee of the Board of Directors. In connection with the Separation, we entered into an agreement to modify all outstanding awards granted to the holders of such awards. Each outstanding time or performance-based Aimco award was converted into one share of Aimco common stock and one share of AIR common stock. Generally, all such Aimco equity awards retain the same terms and vesting conditions as the original Aimco equity awards immediately before the Separation. Following the Separation, compensation expense related to these modified awards for the employees retained by Aimco is incurred by Aimco. The compensation expense related to these modified awards for employees of AIR is incurred by AIR. For the year ended December 31, 2020, total compensation cost recognized for share-based awards was (in thousands): 2020 (4) Share-based compensation expense (1) $ 1,070 Capitalized share-based compensation (2) 138 Total share-based compensation (3) $ 1,208 (1) Amounts are recorded in general and administrative expenses in our consolidated statements of operations. (2) Amounts are recorded in buildings and improvements on the consolidated balance sheets. (3) Amounts are recorded in additional paid-in capital and common noncontrolling interests in the Aimco Operating Partnership on the Aimco consolidated balance sheets, and in general partner and special limited partner and limited partners on the Aimco Operating Partnership consolidated balance sheets. (4) Amounts include share-based compensation costs allocated by Aimco Predecessor of $1.2 million. As of December 31, 2020, our share of total unvested compensation cost not yet recognized was $1.5 million. We expect to recognize this compensation cost over a weighted-average period of approximately 1.5 years. We grant stock options and restricted stock awards that are subject to time-based vesting and require continuous employment, typically over a period of four years from the grant date, and we refer to these awards as Time-Based Stock Options and Time-Based Restricted Stock, respectively. We also grant stock options, restricted stock awards, and two forms of long-term incentive partnership units (“LTIP units”), that vest conditioned on Aimco’s total shareholder return (“TSR”), relative to the NAREIT Equity Apartment Index (60% weighting) and the MSCI US REIT Index (40% weighting) over a forward-looking performance period of three years . We refer to these awards as TSR Stock Options, TSR Restricted Stock, TSR LTIP I units, and TSR LTIP II units. Vested LTIP II units may be converted at the holders’ option to LTIP Units for a conversion price over a term of 10 years . Earned TSR-based awards, if any, will vest 50 % on each of the third anniversary and fourth anniversary of the grant date, based on continued employment. Our Time-Based Stock Options and TSR Stock Options expire generally 10 years from the date of grant. We recognize compensation cost associated with time-based awards ratably over the requisite service periods, which are typically four years. We recognize compensation cost related to the TSR-based awards, which have graded vesting periods, over the requisite service period for each separate vesting tranche of the award, commencing on the grant date. The value of the TSR-based awards takes into consideration the probability that the market condition will be achieved; therefore, previously recorded compensation cost is not adjusted in the event that the market condition is not achieved, and awards do not vest. We had Time-Based Stock Options, Time-Based Restricted Stock, TSR Stock Options, TSR Restricted Stock, TSR LTIP I units and TSR LTIP II units outstanding as of December 31, 2020. The following table summarizes the unvested or outstanding shares issued to employees of Aimco and AIR, and are potentially dilutive to Aimco and Aimco Operating Partnership as of December 31, 2020. Unvested Compensation Unvested shares Not Yet Recognized (2) Awards Aimco AIR (in thousands) Time-Based Stock Options (Outstanding shares) — 238,530 $ — TSR Stock Options (Outstanding shares) — 589,323 — Time-Based Restricted Stock Awards 21,473 73,190 608 TSR Restricted Stock Awards (1) 33,912 188,936 393 TSR LTIP I units 22,911 112,739 439 TSR LTIP II units 8,334 1,104,008 50 Total awards 86,630 2,306,726 $ 1,490 (1) The unvested awards are based on the target performance payout. (2) Unvested compensation not yet recognized represents Aimco’s compensation cost for Aimco employees. Compensation costs related to shares issued to AIR employees is recognized by AIR.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 14 — Fair Value Measurements Recurring Fair Value Measurements During the year ended December 31, 2020, Aimco Predecessor paid an upfront premium of $12.1 million for the option to enter into a cash-settled interest rate swap at a future date. This interest rate option, or swaption, provides partial protection against our refinancing interest rate risk and is intended to mitigate interest rate increases between now and 2024. We receive a cash settlement in the future if the prevailing interest rate is higher than the 1.68% strike price. The amount of future cash settlement is capped if the prevailing interest rate exceeds 2.78%. Alternatively, if interest rates were to decrease below the specified strike price, we would not receive a cash settlement. We measure at fair value on a recurring basis our interest rate option, which is presented in other assets, net in our consolidated balance sheets. Our interest rate option is classified within Level 2 of the GAAP fair value hierarchy, and we estimate its fair value using pricing models that rely on observable market information, including contractual terms, market prices, and interest rate yield curves. The fair value adjustment is included in earnings in other expense, net, in our consolidated statements of operations. Changes in fair value are reflected as a non-cash transaction in adjustments to arrive at cash flows from operations, and the upfront premium is reflected in other financing activities in our consolidated statements of cash flows. As of December 31, 2020, we have investments of $2.3 million in RET Ventures consisting of three privately held entities that develop technology related to the real estate industry. These investments are measured at net asset value (“NAV”) as a practical expedient under ASC 820. See Note 15 for further details for RET Ventures unfunded commitments. The following table summarizes the fair value of our interest rate option and our investment in RET Ventures as of December 31, 2020 and 2019 (in thousands): As of December 31, 2020 As of December 31, 2019 Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Interest rate option $ 13,315 $ — $ 13,315 $ — $ — $ — $ — $ — Investment in RET Ventures (1) 2,293 — — — 752 — — — (1) Investments measured at fair value using the NAV practical expedient are not classified in the fair value hierarchy. Financial Assets and Liabilities Not Measured at Fair Value We believe that the carrying value of the consolidated amounts of cash and cash equivalents, accounts receivables and payables approximated their fair value as of December 31, 2020 and 2019, due to their relatively short-term nature and high probability of realization. We estimate the fair value of our non-recourse property debt and Notes Payable to AIR using an income and market approach, including comparison of the contractual terms to observable and unobservable inputs such as market interest rate risk spreads, contractual interest rates, remaining periods to maturity, and loan to value ratios on similarly encumbered apartment communities within our portfolio. We classify the fair value of our non-recourse property debt and Notes Payable to AIR within Level 2 of the GAAP valuation hierarchy based on the significance of certain observable inputs used to estimate its fair value. The carrying amount of the Notes Payable to AIR approximated their fair value at both December 31, 2020 and 2019. The following table summarizes carrying value and fair value of our non-recourse property debt as of December 31, 2020 and 2019 (in thousands): As of December 31, 2020 2019 Carrying Value Fair Value Carrying Value Fair Value Non-recourse property debt $ 449,510 $ 467,010 $ 493,886 $ 499,841 Nonrecurring Fair Value Measurements Immediately following the Separation, we tested our right of use assets, tenant improvements, furniture, fixtures and equipment and our internally developed software for impairment. We concluded that the estimated fair value of the related assets no longer exceeded their carrying values and recorded an aggregate impairment of $15.9 million. The fair value determination included assumptions based on Level 3 inputs. See Note 2 for further details. There were no such impairments in 2019.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 15 — Commitments and Contingencies Commitments In connection with our redevelopment and other capital activities, we have entered into various construction-related contracts and we have made commitments to complete certain projects. As of December 31, 2020, our commitments related to these projects totaled approximately $3.2 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. We have a commitment to fund an additional $37.5 million to IQHQ and currently expect to incur this investment over the next two years. We also have unfunded commitments related to RET Ventures in the amount of $1.1 million, the timing of which is uncertain. Legal Matters For legal liabilities that relate to occurrences prior to the Separation, including environmental liabilities related to properties that were no longer owned by Aimco or AIR at the time of the Separation, pursuant to the terms of the Separation Agreement, Aimco Operating Partnership will bear the first $17.5 million of such liabilities, in the aggregate, and AIR Operating Partnership will bear any such liabilities in excess of $17.5 million. See Note 5 for further details.

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Business Segments	Note 16 — Business Segments We evaluated the information reviewed by our chief executive officer, who is our chief operating decision maker (“CODM”), to assess our operating performance. We have determined we have three segments: (i) Development and redevelopment, (ii) Operating Portfolio, and (iii) Other. Our Development and redevelopment segment includes residential apartment communities, including associated commercial space, that are under construction or have not achieved stabilization. Our Operating Portfolio segment includes majority owned residential communities that have a achieved stabilized level of operations as of January 1, 2019 and maintained it throughout the current year and comparable period. We aggregate all our apartment communities that have reached a stabilization into our Operating Portfolio. Our Other segment consists of 1001 Brickell Bay Drive, our only commercial real estate property. We realigned our segments during the fourth quarter 2020 and have restated historical periods to conform with current segment presentation. Our CODM uses cash flow, construction timeline to completion and actual versus budgeted results to evaluate our properties in our Development and redevelopment segment. Our CODM uses proportionate property net operating income to assess the operating performance of our Operating Portfolio. Proportionate property net operating income is defined as our share of rental and other property revenues, excluding reimbursements, less direct property operating expenses, net of utility reimbursements, for consolidated communities. In our consolidated statements of operations, utility reimbursements are included in rental and other property revenues, in accordance with GAAP. As of December 31, 2020, our Development and redevelopment segment includes two communities under development or redevelopment, Upton Place and Hamilton on the Bay. Our Operating Portfolio segment includes twenty four consolidated communities with 6,067 apartment homes (apartment homes unaudited). Our Other segment includes one office building. The following tables present the revenues, proportionate property net operating income, and income before income tax benefit (expense) of our segments on a proportionate basis, excluding amounts related to our proportionate share of four apartment communities with 142 apartment homes that we neither managed nor consolidated, for the years ended December 31, 2020, 2019, and 2018 (in thousands): Development and Redevelopment Operating Portfolio Other Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments Consolidated Year ended December 31, 2020: Rental and other property revenues $ 1,515 $ 130,689 $ 12,986 $ 6,196 $ 65 $ 151,451 Property operating expenses 981 43,891 4,148 5,702 6,792 61,514 Other operating expenses not allocated to segments (2) — — — — 104,294 104,294 Total operating expenses 981 43,891 4,148 5,702 111,086 165,808 Proportionate property net operating income 534 86,798 8,838 494 (111,021 ) (14,357 ) Other items included in loss before income tax benefit (3) — — — — (1,563 ) (1,563 ) Loss before income tax benefit $ 534 $ 86,798 $ 8,838 $ 494 $ (112,584 ) $ (15,920 ) Development and Redevelopment Operating Portfolio Other Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments Consolidated Year ended December 31, 2019: Rental and other property revenues $ — $ 131,346 $ 6,888 $ 5,458 $ — $ 143,692 Property operating expenses — 42,962 1,931 5,202 7,446 57,541 Other operating expenses not allocated to segments (2) — — — — 71,092 71,092 Total operating expenses — 42,962 1,931 5,202 78,538 128,633 Proportionate property net operating income — 88,384 4,957 256 (78,538 ) 15,059 Other items included in loss before income tax benefit (3) — — — — (18,247 ) (18,247 ) Loss before income tax benefit $ — $ 88,384 $ 4,957 $ 256 $ (96,785 ) $ (3,188 ) Development and Redevelopment Operating Portfolio Other Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments Consolidated Year ended December 31, 2018: Rental and other property revenues $ — $ 127,368 $ — $ 4,795 $ — $ 132,163 Property operating expenses — 41,778 — 4,795 6,979 53,552 Other operating expenses not allocated to segments (2) — — — — 55,141 55,141 Total operating expenses — 41,778 — 4,795 62,120 108,693 Proportionate property net operating income — 85,590 — — (62,120 ) 23,470 Other items included in income before income tax expense (3) — — — — (19,798 ) (19,798 ) Income before income tax expense $ — $ 85,590 $ — $ — $ (81,918 ) $ 3,672 (1) Represents adjustments for the redeemable noncontrolling interests in consolidated real estate partnership ’s share of the results of consolidated communities in our segment s , which are included in the related co nsolidated amounts, but excluded from proportionate property net operating income for our segment evaluation. Also includes the reclassification of utility reimbursements from revenues to property operating expenses for the purpose of evaluating segment results. Utility reimbursements are included in rental and other property revenues i n our co nsolidated statements of operations prepared in accordance with GAAP. (2) Other operating expenses not allocated to segments consists of depreciation and amortization, general and administrative expense, and other operating expenses which may include provision for real estate impairment loss, which are not included in our measure of segment performance. (3) Other items included in income before income tax benefit (expense) consists primarily of interest expense for the years ended December 31, 2020, 2019, and 2018, and mezzanine investment income, net, for the year ended December 31, 2020 and 2019. Our properties in the Development and redevelopment segment were not acquired until the year ended December 31, 2020 and therefore, the segment had no assets for the year ended December 31, 2019. Net real estate and non-recourse property debt, net, of our segments as of December 31, 2020 and 2019 were as follows (in thousands): Development and Redevelopment Operating Other Total As of December 31, 2020: Buildings and improvements $ 61,813 $ 772,786 $ 160,517 $ 995,116 Land 56,676 298,459 150,018 505,153 Total real estate 118,489 1,071,245 310,535 1,500,269 Accumulated depreciation (447 ) (469,873 ) (24,690 ) (495,010 ) Net real estate $ 118,042 $ 601,372 $ 285,845 $ 1,005,259 Non-recourse property debt, net $ — $ 447,967 $ — $ 447,967 Development and Redevelopment Operating Portfolio Other Total As of December 31, 2019: Buildings and improvements $ — $ 779,513 $ 158,019 $ 937,532 Land — 298,458 149,422 447,880 Total real estate — 1,077,971 307,441 1,385,412 Accumulated depreciation — (441,390 ) (8,054 ) (449,444 ) Net real estate $ — $ 636,581 $ 299,387 $ 935,968 Non-recourse property debt, net $ — $ 492,638 $ — $ 492,638

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Note 17 — Subsequent Events We, as lessee, and AIR, as lessor, entered into leases of four properties currently under construction or in lease-up. The four properties include (i) North Tower at Flamingo Point in Miami Beach, Florida, (ii) The Fremont Residences on the Anschutz Medical Campus in Aurora, Colorado, (iii) Prism in Cambridge, Massachusetts, and (iv) 707 Leahy Apartments in Redwood City, California. According to the terms of the lease agreements, we have the option to complete the on-going development and redevelopment of such properties and their lease-ups. If we elect such options, following the successful completion of the contemplated development and redevelopments, AIR has the option (and not an obligation) to pay us an amount equal to the difference between the then-current fair market value of the properties and the initial fair market value of the properties at the time of lease inception, at a five percent discount thereto.

Summarized Consolidated Quarter

Summarized Consolidated Quarterly Information (Unaudited)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Summarized Consolidated Quarterly Information (Unaudited)	Note 18 — Summarized Consolidated Quarterly Financial Information (Unaudited) Aimco’s and Aimco Operating Partnership’s summarized consolidated quarterly financial information (unaudited) for the years ended December 31, 2020 and 2019, is provided below (in thousands): In the fourth quarter 2020, we recorded an impairment charge of $15.9 million. See Note 2 for further details. Aimco Year ended December 31, 2020 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenues $ 38,309 $ 37,165 $ 37,328 $ 38,649 Net income (loss) 3,785 3,883 1,996 (15,435 ) Net income (loss) attributable to Aimco common stockholders 3,897 3,994 2,118 (15,050 ) Earnings (loss) per share - basic and diluted $ 0.03 $ 0.03 $ 0.01 $ (0.10 ) Aimco year ended December 31, 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenues $ 35,789 $ 31,889 $ 37,813 $ 38,201 Net income (loss) 1,310 1,178 (1,107 ) (1,268 ) Net income (loss) attributable to Aimco common stockholders 1,322 1,178 (958 ) (1,238 ) Earnings (loss) attributable to Aimco per common share - basic $ 0.01 $ 0.01 $ (0.01 ) $ (0.01 ) Earnings (loss) attributable to Aimco per common share - diluted $ 0.01 $ 0.01 $ (0.01 ) $ (0.01 ) Aimco OP L.P. Year ended December 31, 2020 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenues $ 38,309 $ 37,165 $ 37,328 $ 38,649 Net income (loss) 3,785 3,883 1,996 (15,435 ) Net income (loss) attributable to the Aimco Operating Partnership's common unitholders 4,073 4,175 2,211 (15,769 ) Earnings (loss) attributable to the Aimco Operating Partnership per common unit - basic and diluted $ 0.03 $ 0.03 $ 0.01 $ (0.10 ) Aimco OP L.P. year ended December 31, 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenues $ 35,789 $ 31,889 $ 37,813 $ 38,201 Net income (loss) 1,310 1,178 (1,107 ) (1,268 ) Net income (loss) attributable to the Aimco Operating Partnership's common unitholders 1,493 1,332 (1,102 ) (1,404 ) Earnings (loss) attributable to the Aimco Operating Partnership per common unit - basic $ 0.01 $ 0.01 $ (0.01 ) $ (0.01 ) Earnings (loss) attributable to the Aimco Operating Partnership per common unit - diluted $ 0.01 $ 0.01 $ (0.01 ) $ (0.01 )

Schedule III_ Real Estate and

Schedule III: Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2020
Real Estate And Accumulated Depreciation Disclosure [Abstract]
Schedule III: Real Estate and Accumulated Depreciation	APARTMENT INVESTMENT AND MANAGEMENT COMPANY AIMCO OP L.P. SCHEDULE III: REAL ESTATE AND ACCUMULATED DEPRECIATION December 31, 2020 (In Thousands Except Apartment Home Data) (2) As of December 31, 2020 (1) Initial Cost Cost Capitalized (4) Apartment Community Apartment Date Year Apartment Buildings and Subsequent to Buildings and (3) Accumulated Total Cost (5) Name Type Acquired Location Built Homes Land Improvements Acquisition Land Improvements Total Depreciation (AD) Net of AD Encumbrances Operating: 118-122 West 23rd Street High Rise Jun 2012 New York, NY 1987 42 $ 14,985 $ 23,459 $ 7,291 $ 14,985 $ 30,750 $ 45,735 $ (11,677 ) $ 34,058 $ 16,523 1045 on the Park Apartments Homes Mid Rise Jul 2013 Atlanta, GA 2012 30 2,793 6,662 866 2,793 7,528 10,321 (2,066 ) 8,255 — 2200 Grace High Rise Aug 2018 Lombard, IL 1971 72 642 7,788 480 642 8,268 8,910 (5,098 ) 3,812 7,311 2900 on First Apartments Mid Rise Oct 2008 Seattle, WA 1989 135 19,070 17,518 33,767 19,070 51,285 70,355 (30,596 ) 39,759 — 173 E. 90th Street High Rise May 2004 New York, NY 1910 72 12,066 4,535 8,910 12,066 13,445 25,511 (5,389 ) 20,122 — 237-239 Ninth Avenue High Rise Mar 2005 New York, NY 1900 36 8,495 1,866 3,010 8,495 4,876 13,371 (3,331 ) 10,040 — Bank Lofts High Rise Apr 2001 Denver, CO 1920 125 3,525 9,045 5,698 3,525 14,743 18,268 (8,400 ) 9,868 — Bluffs at Pacifica, The Garden Oct 2006 Pacifica, CA 1963 64 8,108 4,132 16,952 8,108 21,084 29,192 (11,964 ) 17,228 — Cedar Rim Garden Apr 2000 Newcastle, WA 1980 104 761 5,218 14,706 761 19,924 20,685 (15,201 ) 5,484 — Elm Creek Mid Rise Dec 1997 Elmhurst, IL 1987 400 5,910 30,830 31,941 5,910 62,771 68,681 (37,480 ) 31,201 49,119 Evanston Place High Rise Dec 1997 Evanston, IL 1990 190 3,232 25,546 17,069 3,232 42,615 45,847 (22,539 ) 23,308 — Hillmeade Garden Nov 1994 Nashville, TN 1986 288 2,872 16,070 21,782 2,872 37,852 40,724 (23,900 ) 16,824 26,121 Hyde Park Tower High Rise Oct 2004 Chicago, IL 1990 155 4,731 14,927 16,415 4,731 31,342 36,073 (13,452 ) 22,621 — Pathfinder Village Garden Jan 2006 Fremont, CA 1973 246 19,595 14,838 21,463 19,595 36,301 55,896 (20,344 ) 35,552 55,000 Plantation Gardens Garden Oct 1999 Plantation ,FL 1971 372 3,773 19,443 21,803 3,773 41,246 45,019 (26,499 ) 18,520 31,719 Royal Crest Estates Garden Aug 2002 Warwick, RI 1972 492 22,433 24,095 5,552 22,433 29,647 52,080 (21,366 ) 30,714 — Royal Crest Estates Garden Aug 2002 Nashua, NH 1970 902 68,230 45,562 16,122 68,230 61,684 129,914 (46,931 ) 82,983 88,446 Royal Crest Estates Garden Aug 2002 Marlborough, MA 1970 473 25,178 28,786 16,040 25,178 44,826 70,004 (32,266 ) 37,738 60,828 St. George Villas Garden Jan 2006 St. George, SC 1984 40 108 1,024 423 108 1,447 1,555 (1,330 ) 225 283 Waterford Village Garden Aug 2002 Bridgewater, MA 1971 588 29,110 28,101 11,511 29,110 39,612 68,722 (31,341 ) 37,381 — Wexford Village Garden Aug 2002 Worcester, MA 1974 264 6,349 17,939 5,039 6,349 22,978 29,327 (15,007 ) 14,320 — Willow Bend Garden May 1998 Rolling Meadows, IL 1969 328 2,717 15,437 19,975 2,717 35,412 38,129 (26,224 ) 11,905 — Yacht Club at Brickell High Rise Dec 2003 Miami, FL 1998 357 31,362 32,214 18,583 31,362 50,797 82,159 (22,022 ) 60,137 84,548 Yorktown Apartments High Rise Dec 1999 Lombard, IL 1971 292 2,413 10,374 51,981 2,413 62,355 64,768 (35,453 ) 29,315 29,612 Total Operating Portfolio 6,067 298,458 405,409 367,379 298,458 772,788 1,071,246 (469,876 ) 601,370 449,510 Development and redevelopment: Hamilton on the Bay High Rise Aug 2020 Miami, FL 1985 275 56,649 34,891 2,242 56,677 37,105 93,782 (446 ) 93,336 — Upton Place Dec 2020 Washington, DC — — 21,280 3,426 — 24,706 24,706 — 24,706 — Total Development and redevelopment 275 56,649 56,171 5,668 56,677 61,811 118,488 (446 ) 118,042 — Other: 1001 Brickell Bay Drive High Rise Jul 2019 Miami, FL 1985 — 149,422 152,791 8,321 150,018 160,517 310,535 (24,688 ) 285,847 — Total Portfolio 6,342 504,529 614,371 381,368 505,153 995,116 1,500,269 (495,010 ) 1,005,259 449,510 (1) Date we acquired the apartment community or first acquired the partnership that owns the community. (2) Includes costs capitalized since acquisition or date of initial acquisition of the community. (3) The aggregate cost of land and depreciable property for federal income tax purposes was approximately $1.2 billion as of December 31, 2020. (4) Depreciable life for buildings and improvements ranges from five to 30 years and is calculated on a straight-line basis. (5) Encumbrances are presented before reduction for debt issuance costs and the impact of assumed debt fair value adjustment.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation We consolidate variable interest entities (“VIE”), in which we are considered the primary beneficiary. The primary beneficiary is the entity that has (i) the power to direct the activities that most significantly impact the entity's economic performance and (ii) the obligation to absorb losses of the VIE or the right to receive benefits from the VIE that could be significant to the VIE. As used herein, and except where the context otherwise requires, “partnership” refers to a limited partnership or a limited liability company and “partner” refers to a partner in a limited partnership or a member of a limited liability company. Certain reclassifications have been made to prior period amounts to conform to the current period financial statement presentation with no effect on the Company’s previously reported results of operations, financial position, or cash flows.
Allocations	Allocations The consolidated statements of operations include allocations of general and administrative expenses from Aimco Predecessor, as discussed in Note 5 —Transactions with AIR. We consider the basis on which expenses have been allocated to be a reasonable reflection of the utilization of services provided to or the benefit received by us during the periods presented. However, the allocations may not include all the actual expenses that we would have incurred and may not reflect our consolidated results of operations, financial position, and cash flows had it been a stand-alone company during the periods presented. Actual costs that might have been incurred had we been a stand-alone company would depend on a number of factors, including the chosen organizational structure, what functions we might have performed ourselves or outsourced, and strategic decisions we might have made in areas such as information technology and infrastructure. Following the Separation, AIR, through its subsidiaries, provides Aimco with certain property management and other services, and we perform certain functions using our own resources or purchase services from third parties.
Common Noncontrolling Interest in Aimco Operating Partnership	Common Noncontrolling Interests in Aimco Operating Partnership Common noncontrolling interests in Aimco Operating Partnership consist of common OP Units and are reflected in Aimco’s accompanying consolidated balance sheets as common noncontrolling interests in Aimco Operating Partnership. The Aimco Operating Partnership’s income or loss is allocated to the holders of common OP Units, other than Aimco, based on the weighted-average number of common OP Units (including Aimco) outstanding during the period. During the years ended December 31, 2020, 2019, and 2018, the holders of common OP Units had a weighted-average economic ownership interest in the Aimco Operating Partnership of 5.4% Redeemable Noncontrolling Interest in Consolidated Real Estate Partnerships Redeemable noncontrolling interest consists of equity interests held by a limited partner in a consolidated real estate partnership that has a finite life. We generally attribute to noncontrolling interests their share of income or loss of consolidated partnerships based on their proportionate interest in the results of operations of the partnerships, including their share of losses even if such attribution results in a deficit noncontrolling interest balance within our equity accounts. If a real estate partnership includes redemption rights that are not within our control, the noncontrolling interest is included as temporary equity. If the redemption right is not currently redeemable but probable of being redeemable in the future, changes in redemption value are recognized each quarter with the change in value being reflected in additional paid-in-capital. The assets of our consolidated real estate partnerships must first be used to settle the liabilities of the consolidated real estate partnerships. The consolidated real estate partnership’s creditors do not have recourse to the general credit of the Aimco Operating Partnership. The following table represents a reconciliation of our redeemable noncontrolling interest in consolidated real estate partnerships during the year ended December 31, 2020 (in thousands): Balance at December 31, 2019 $ 4,720 Net loss (457 ) Balance at December 31, 2020 $ 4,263
Investments in Unconsolidated Real Estate Partnership	Investments in Unconsolidated Real Estate Partnerships We own general and limited partner interests in partnerships that either directly, or through interests in other real estate partnerships, own apartment communities. We generally account for investments in real estate partnerships that we do not consolidate under the equity method. Accordingly, we recognize our share of the earnings or losses of the entity for the periods presented, inclusive of our share of any impairments and disposition gains or losses recognized by and related to such entities, and we present such amounts within income from unconsolidated real estate partnerships in our c onsolidated statements of operations. The excess of our cost of the acquired partnership interests over our share of the partners’ equity or deficit is generally ascribed to the fair values of land and buildings owned by the partnerships. We amortize the excess cost ascribed to the buildings over the related estimated useful lives. Such amortization is recorded as an adjustment of the amounts of earnings or losses we recognize from such unconsolidated real estate partnerships. We may also originate loans for real estate acquisitions or developments where we either expect, or have the opportunity, to participate in the residual profits from such projects. When the risks and rewards of these arrangements are similar to an equity investor or joint venture partner, we account for these arrangements as real estate investments using the equity method of accounting. We recognize as income changes in our share of net assets, adjusted for any basis differential, in mezzanine investment income, net, in our consolidated . We assess the recoverability of our equity method investments if there are indicators of potential impairment. We did not recognize any such impairments of our equity method investments during the years ended December 31, 2020, 2019, and 2018. Mezzanine Investment The Separation Agreement provides for AIR to transfer ownership of the subsidiaries that originated and hold the mezzanine loan to the partnership owning Parkmerced Apartments, the related equity option and the interest rate option, or swaption, that provides partial protection against future refinancing risk through 2024 once required consents to transfer are received. At the time of the Separation and as of March 12, 2021, AIR retained legal ownership of these subsidiaries. Until ownership of the subsidiaries is transferred, AIR is obligated to pass payments on such loan to us, and we are obligated to indemnify AIR against any costs and expenses related thereto. We have the risks and rewards of ownership of the Mezzanine Investment and have recognized an asset related to our right to receive the Mezzanine Investment from AIR. Prior to the Separation, consistent with the presentation of the consolidated financial statements on a carve out basis and considering intent to legally transfer the subsidiaries holding the mezzanine investment and related assets in connection with the Separation, the Mezzanine Investment was accounted for as an equity method investment. Accordingly, we recognized as income changes in our share of net assets, adjusted for any basis differential, in mezzanine investment income, net, in our consolidated statements of operations. Subsequent to the Separation, we recognize as income the net amounts recognized by AIR on its equity investment that are due to be paid to us when collected, which primarily represent the interest accrued under the terms of the underlying mezzanine loan. As of December 31, 2020, the Mezzanine Investment in our consolidated balance sheets represents the assets associated with our indirect interest in the subsidiary that owns Parkmerced Apartments, which we do not consolidate.
Real Estate	Real Estate Acquisitions Upon the acquisition of real estate, we determine whether the purchase qualifies as an asset acquisition or, less frequently, meets the definition of an acquisition of a business. We generally recognize the acquisition of real estate or interests in partnerships that own real estate at our cost, including the related transaction costs, as asset acquisitions. We allocate the cost of real estate acquired based on the relative fair value of the assets acquired and liabilities assumed. The fair value of these assets and liabilities is determined using valuation techniques that rely on Level 2 and Level 3 inputs within the fair value framework. We determine the fair value of tangible assets, such as land, buildings, furniture, fixtures, and equipment using valuation techniques that consider comparable market transactions, replacement costs, and other available information. We determine the fair value of identified intangible assets or liabilities, which typically relate to in-place leases, using valuation techniques that consider the terms of the in-place leases, current market data for comparable leases, and our experience in leasing similar real estate. The intangible assets or liabilities related to in-place leases are comprised of: (a) the value of the above- and below-market leases in-place, measured over the period, including probable lease renewals for below-market leases, for which the leases are expected to remain in effect; (b) the estimated unamortized portion of avoided leasing commissions and other costs that Capital Additions We capitalize costs, including certain indirect costs, incurred in connection with our capital additions activities, including redevelopments, other tangible apartment community improvements, and replacements of existing community components. Included in these capitalized costs are payroll costs associated with time spent by employees in connection with the planning, execution, and control of all capital addition activities at our communities. We characterize as “indirect costs” an allocation of certain department costs, including payroll, at the area operations and corporate levels that clearly relate to capital addition activities. We also capitalize interest, property taxes, and insurance during periods in which construction projects are in progress. We commence capitalization of costs, including certain indirect costs, incurred in connection with our capital addition activities, at the point in time when activities necessary to get communities, apartment homes, or leased spaces ready for their intended use begin. These activities include when communities, apartment homes or leased spaces are undergoing physical construction, as well as when homes or leased spaces are held vacant in advance of planned construction, provided that other activities such as permitting, planning, and design are in progress. We cease the capitalization of costs when the communities or components thereof are substantially complete and ready for their intended use, which is typically when construction has been completed and homes or leased spaces are available for occupancy. We charge costs including ordinary repairs, maintenance, and resident turnover costs to property operating expense, as incurred . For the each of the years ended December 31, 2020, 2019, and 2018, we capitalized to buildings and improvements $1.0 million, $0.2 million, and $0.3 million of interest costs, respectively. For the years ended December 31, 2020, 2019, and 2018, we capitalized to buildings and improvements $2.7 million, $4.1 million, and $4.9 million of indirect costs, respectively. Gain or Loss on Dispositions Gain or loss on dispositions are recognized when we no longer hold a controlling financial interest in the real estate and sufficient consideration has been received. Upon disposition, the related assets and liabilities are derecognized, and the gain or loss on disposition is recognized as the difference between the carrying amount of those assets and liabilities and the value of consideration received. There were no dispositions in the years ended December 31, 2020, 2019, and 2018.
Impairment	Impairment Real estate and other long-lived assets to be held and used are stated at cost, less accumulated depreciation and amortization, unless the carrying amount of the asset is not recoverable. If events or circumstances indicate that the carrying amount of an asset may not be recoverable, we assess its recoverability by comparing the carrying amount to our estimate of the undiscounted future cash flows, excluding interest charges, of the community. If the carrying amount exceeds the aggregate undiscounted future cash flows, we recognize an impairment loss to the extent the carrying amount exceeds the estimated fair value of the community. In connection with the Separation, we entered into a sublease of office space within our corporate offices to AIR at then-current market rents. Based on an analysis of the estimated undiscounted cash flows relative to the sublease arrangement, we evaluated the recoverability of the assets associated with the subleased space, including, the right-of-use asset, tenant improvements and furniture, fixtures and equipment and concluded the subleased assets were impaired. We recorded an impairment charge of $11.0 million in our consolidated statements of operations for the year ended December 31, 2020. There were no such impairments for the years ended December 31, 2019 and 2018. In connection with the Separation, we entered into a software license agreement with AIR to provide for the use of certain internally developed software at then-current market rates. Based on an analysis of the estimated undiscounted cash flows relative to the carrying value of the internally developed software, we concluded the assets were impaired. Additionally, following an evaluation of the future service potential of certain other internal software that was under development, we ceased development and impaired the associated carrying value. We recorded an aggregate impairment charge of $4.9 million in our consolidated statements of operations for the year ended December 31, 2020. There were no such impairments for the years ended December 31, 2019 and 2018.
Cash Equivalents	Cash Equivalents We classify highly liquid investments with an original maturity of three months or less as cash equivalents. We maintain cash equivalents in financial institutions in excess of insured limits. We have not experienced any losses in these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions. Supplemental cash flow information for the years ended December 31, 2020, 2019 and 2018 is as follows: 2020 2019 2018 SUPPLEMENTAL CASH FLOW INFORMATION: Interest paid, net of amounts capitalized $ 22,152 $ 17,748 $ 19,296 Cash paid for income taxes 9,216 1,773 284 Non-cash transactions associated with the acquisition of real estate: Non-recourse property debt assumed in connection with the acquisition of real estate — 66,779 — Contributions from Aimco Predecessor 955 — — Contribution from noncontrolling interest in consolidated real estate partnerships 11,667 — — Deferred tax liability assumed in connection with the acquisition of real estate — 148,809 — Other non-cash transactions: Accrued capital expenditures (at end of period) 1,641 1,966 3,964 Non-recourse property debt assumed with collateral substitution — — 72,296 Issuance of Notes Payable to AIR in connection with the Separation 534,127 — — Contributions from Aimco Predecessor, net 131,447 — — Restricted Cash Restricted cash consists of tenant security deposits, capital replacement reserves, insurance reserves, and cash restricted as required by our debt agreements.
Other Assets	O ther Assets As of December 31, 2020, and 2019, other assets were comprised of the following amounts (in thousands): 2020 2019 Intangible lease assets, net $ 7,264 $ 13,380 Accounts receivable, net of allowances of $1,467 and $80 as of December 31, 2020 and 2019, respectively 2,660 2,313 Prepaid expenses and real estate taxes 10,493 2,991 Investment in IQHQ 12,500 — Corporate fixed assets 12,860 — Deferred costs, deposits, and other 17,557 2,354 Total other assets, net $ 63,334 $ 21,038
Intangibles	Intangibles Intangible lease assets are included in other assets, net and intangible lease liabilities are included in accrued liabilities and other on the consolidated balance sheets. The following table details intangible lease assets and liabilities, net of accumulated amortization, for the years ended December 31, 2020, and 2019 (in thousands). 2020 2019 In-place leases and leasing costs $ 17,203 $ 16,355 Above-market leases 146 145 Less: accumulated amortization (10,085 ) (3,120 ) Intangible lease assets, net $ 7,264 $ 13,380 Below-market leases $ 4,886 $ 4,219 Less: accumulated amortization (2,366 ) (633 ) Intangible lease liabilities, net $ 2,520 $ 3,586 Based on the balance of intangible lease assets and liabilities as of December 31, 2020, the net aggregate amortization for the next five years and thereafter is expected to be as follows (in thousands). In-place leases and leasing costs Below-market leases 2021 $ 3,938 $ 1,201 2022 1,944 676 2023 830 321 2024 346 176 2025 206 146 Thereafter — — Total future amortization $ 7,264 $ 2,520
Accounts Receivable, net and Straight-line rent	Accounts Receivable, net and Straight-line rent We present our accounts receivable and straight-line rent receivable net of allowances for amounts that may not be collected. The allowance is determined based on an assessment on whether substantially all of the amounts due from the resident or tenant is probable of collection. This includes a specific tenant analysis and aging analysis.
Deferred Leasing Costs	Deferred Leasing Costs Beginning in 2019, in accordance with the adoption of Accounting Standard Codification (“ASC”) 842, we defer leasing costs incremental to a lease that we would not have incurred if the contract had not been obtained. Amortization of these costs is included in depreciation and amortization. Prior to 2019, we deferred leasing commissions and other direct costs incurred in connection with successful leasing efforts and amortized the costs over the terms of the related leases.
Revenue from Leases	Revenue from Leases We are a lessor for residential and commercial leases. Our operating leases with residents may provide that the resident reimburse us for certain costs, primarily the resident’s share of utilities expenses, incurred by the apartment community. Our operating leases with commercial tenants may provide that the tenant reimburse us for common area maintenance, real estate taxes, and other recoverable costs incurred by the commercial property. Beginning in 2019, with the adoption of ASC 842, we concluded that residential and commercial reimbursements represent revenue attributable to non-lease components for which the timing and pattern of recognition is the same as the revenue for the lease components. We adopted the practical expedient that allows us to account for the lease and non-lease components as a single component. Reimbursements and the related expenses are presented on a gross basis in our consolidated statements of operations, with the reimbursements included in rental and other property revenues in our consolidated statements of operations in the period the recoverable costs are incurred. We recognize rental revenue attributed to lease components, net of any concessions, on a straight-line basis over the term of the lease.
Debt Issuance Costs	Debt Issuance Costs We defer, as debt issuance costs, lender fees and other direct costs incurred in obtaining new financing and amortize the amounts over the terms of the related loan agreements. In connection with the modification of existing financing arrangements, we defer lender fees and amortize these costs and any unamortized debt issuance costs over the term of the modified loan agreement. Debt issuance costs associated with non-recourse property debt are presented as a direct deduction from the related liabilities in our consolidated balance sheets. For debt issuance costs associated with our revolving credit facilities and construction loans that have not been drawn we record the costs in other assets, net in our consolidated balance sheets and amortize the costs to interest expense, on a straight-line basis over the term of the arrangement. Debt issuance costs associated with construction loans are reclassified as a direct deduction to the construction loan liability in proportion to any draws on the loans in our consolidated balance sheets and subsequently amortized to interest expense on a straight-line basis over the remaining term of the arrangement in our consolidated statements of operations. When financing arrangements are repaid or otherwise extinguished prior to maturity, unamortized debt issuance costs are written off. Any lender fees or other costs incurred in connection with an extinguishment are recognized as expense. Amortization and write-off of debt issuance costs and other extinguishment costs are included in interest expense in our consolidated statements of operations.
Depreciation And Amortization	Depreciation and Amortization Depreciation for all tangible assets is calculated using the straight-line method over their estimated useful lives. Acquired buildings and improvements are depreciated over a useful life based on the age, condition, and other physical characteristics of the asset. Furniture, fixtures, and equipment are generally depreciated over five years. We depreciate capitalized costs using the straight-line method over the estimated useful life of the related improvement, which is generally 5, 15, or 30 years. We also capitalize payroll and other indirect costs incurred in connection with preparing an asset for its intended use. These costs include corporate-level costs that clearly relate to the capital addition activities, which we allocate to the applicable assets. All capitalized payroll costs and indirect costs are allocated to capital additions proportionately based on direct costs and depreciated over the estimated useful lives of such capital additions. Purchased equipment is recognized at cost and depreciated using the straight-line method over the estimated useful life of the asset, which is generally five years. Leasehold improvements are also recorded at cost and depreciated on a straight-line basis over the shorter of the asset’s estimated useful life or the term of the related lease. Certain homogeneous items that are purchased in bulk on a recurring basis, such as appliances, are depreciated using group methods that reflect the average estimated useful life of the items in each group. Except in the case of casualties, where the net book value of the lost asset is written off in the determination of casualty gains or losses, we generally do not recognize any loss in connection with the replacement of an existing community component because normal replacements are considered in determining the estimated useful lives used in connection with our composite and group depreciation methods.
Income Tax	Income Taxes Aimco has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), commencing with its taxable year ended December 31, 1994, and it intends to continue to operate in such a manner. Our current and continuing qualification as a REIT depends on its ability to meet the various requirements imposed by the Internal Revenue Code, which are related to organizational structure, distribution levels, diversity of stock ownership and certain restrictions with regard to owned assets and categories of income. If Aimco qualifies for taxation as a REIT, it will generally not be subject to United States federal corporate income tax on our taxable income that is currently distributed to stockholders. This treatment substantially eliminates the “double taxation” (at the corporate and stockholder levels) that generally results from an investment in a corporation. Even if Aimco qualifies as a REIT, it may be subject to United States federal income and excise taxes in various situations, such as on undistributed income. Aimco also will be required to pay a 100% tax on any net income on non-arm’s length transactions between it and a TRS (described below) and on any net income from sales of apartment communities that were held for sale in the ordinary course. The state and local tax laws may not conform to the United States federal income tax treatment, and Aimco may be subject to state or local taxation in various state or local jurisdictions, including those in which we transact business. Any taxes imposed on us reduce our operating cash flow and net income. Certain of Aimco’s operations or a portion thereof, including property management and risk management, are conducted through taxable REIT subsidiaries, which are our subsidiaries of the Aimco Operating Partnership, and each of which we refer to as a TRS. A TRS is a subsidiary C-corporation that has not elected REIT status and, as such, is subject to United States federal corporate income tax. We use TRS entities to facilitate our ability to offer certain services and activities to our residents and investment partners that cannot be offered directly by a REIT. We also use TRS entities to hold investments in certain apartment communities. For our TRS entities, deferred income taxes result from temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for United States federal income tax purposes, and are measured using the enacted tax rates and laws that are expected to be in effect when the differences reverse. We reduce deferred tax assets by recording a valuation allowance when we determine, based on available evidence, that it is more likely than not that the assets will not be realized. We recognize the tax consequences associated with intercompany transfers between the A imco Operating Partnership and TRS entities when such transactions occur. Please refer to Note 9 for further information about our income taxes.
Earnings Per Share And Per Unit	Earnings per Share and per Unit We and the Aimco Operating Partnership calculate earnings per share and unit based on the weighted-average number of shares of common stock or common OP units, participating securities, common stock or common unit equivalents and dilutive convertible securities outstanding during the period. The Aimco Operating Partnership considers both common OP units and equivalents, which have identical rights to distributions and undistributed earnings, to be common units for purposes of the earnings per unit computations. Please refer to Note 12 for further information regarding earnings per share and unit computations.
Use of Estimates	Use of Estimates The preparation of our consolidated financial statements in conformity with US GAAP requires management to make estimates and assumptions that affect the reported amounts included in the consolidated financial statements and accompanying notes thereto. Actual results could differ from those estimates.
Accounting Pronouncements Adopted in the Current Year	Accounting Pronouncements Adopted in the Current Year Effective January 1, 2020, we adopted ASC 326, Financial Instruments-Credit Losses,
Recent Accounting Pronouncements	Recent Accounting Pronouncements On January 2020, the FASB issued Accounting Standard Update (“ASU”) 2020-01, Investment – Equity Securities Investments – Equity Method and Joint Venture Derivatives and Hedging Debt - Debt with Conversion and Other Options Derivatives and Hedging – Contracts in Entity’s Own Equity
Fair Value of Financial Instruments	We measure at fair value on a recurring basis our interest rate option, which is presented in other assets, net in our consolidated balance sheets. Our interest rate option is classified within Level 2 of the GAAP fair value hierarchy, and we estimate its fair value using pricing models that rely on observable market information, including contractual terms, market prices, and interest rate yield curves. The fair value adjustment is included in earnings in other expense, net, in our consolidated statements of operations. Changes in fair value are reflected as a non-cash transaction in adjustments to arrive at cash flows from operations, and the upfront premium is reflected in other financing activities in our consolidated statements of cash flows Financial Assets and Liabilities Not Measured at Fair Value

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Schedule of Supplemental Cash Flow Information	Supplemental cash flow information for the years ended December 31, 2020, 2019 and 2018 is as follows: 2020 2019 2018 SUPPLEMENTAL CASH FLOW INFORMATION: Interest paid, net of amounts capitalized $ 22,152 $ 17,748 $ 19,296 Cash paid for income taxes 9,216 1,773 284 Non-cash transactions associated with the acquisition of real estate: Non-recourse property debt assumed in connection with the acquisition of real estate — 66,779 — Contributions from Aimco Predecessor 955 — — Contribution from noncontrolling interest in consolidated real estate partnerships 11,667 — — Deferred tax liability assumed in connection with the acquisition of real estate — 148,809 — Other non-cash transactions: Accrued capital expenditures (at end of period) 1,641 1,966 3,964 Non-recourse property debt assumed with collateral substitution — — 72,296 Issuance of Notes Payable to AIR in connection with the Separation 534,127 — — Contributions from Aimco Predecessor, net 131,447 — —
Summary of Other Assets	As of December 31, 2020, and 2019, other assets were comprised of the following amounts (in thousands): 2020 2019 Intangible lease assets, net $ 7,264 $ 13,380 Accounts receivable, net of allowances of $1,467 and $80 as of December 31, 2020 and 2019, respectively 2,660 2,313 Prepaid expenses and real estate taxes 10,493 2,991 Investment in IQHQ 12,500 — Corporate fixed assets 12,860 — Deferred costs, deposits, and other 17,557 2,354 Total other assets, net $ 63,334 $ 21,038
Summary of Lease Intangible Assets and Liabilities Net of Accumulated Amortization	Intangible lease assets are included in other assets, net and intangible lease liabilities are included in accrued liabilities and other on the consolidated balance sheets. The following table details intangible lease assets and liabilities, net of accumulated amortization, for the years ended December 31, 2020, and 2019 (in thousands). 2020 2019 In-place leases and leasing costs $ 17,203 $ 16,355 Above-market leases 146 145 Less: accumulated amortization (10,085 ) (3,120 ) Intangible lease assets, net $ 7,264 $ 13,380 Below-market leases $ 4,886 $ 4,219 Less: accumulated amortization (2,366 ) (633 ) Intangible lease liabilities, net $ 2,520 $ 3,586
Schedule of Estimated Aggregate Annual Amortization Expense	Based on the balance of intangible lease assets and liabilities as of December 31, 2020, the net aggregate amortization for the next five years and thereafter is expected to be as follows (in thousands). In-place leases and leasing costs Below-market leases 2021 $ 3,938 $ 1,201 2022 1,944 676 2023 830 321 2024 346 176 2025 206 146 Thereafter — — Total future amortization $ 7,264 $ 2,520
Real Estate Partnership [Member]
Summary of Reconciliation of Redeemable Noncontrolling Interests in Real Estate Partnership	The following table represents a reconciliation of our redeemable noncontrolling interest in consolidated real estate partnerships during the year ended December 31, 2020 (in thousands): Balance at December 31, 2019 $ 4,720 Net loss (457 ) Balance at December 31, 2020 $ 4,263

Significant Transactions (Table

Significant Transactions (Tables)	12 Months Ended
	Dec. 31, 2020
Asset Acquisitions [Member]
Summarized Information Regarding Acquisition	Summarized information regarding these acquisitions is set forth in the table below (in thousands): Purchase price 115,394 Capitalized transaction costs 5,136 Total consideration $ 120,530 Land 56,649 Building and improvements 56,171 Right-of-use lease assets 92,787 Due from affiliates 705 Lease liabilities (86,348 ) Intangible assets (1) 1,517 Below-market lease liabilities (2) (951 ) Total consideration $ 120,530 ( 1) Intangible assets include in-place leases and leasing costs with a weighted-average term of 0.5 years. (2) Below-market leases have a weighted-average term of 0.6 years.

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Lease Income for Operating Leases	Our total lease income was comprised of the following amounts for all operating leases for the year ended December 31, 2020 (in thousands): 2020 2019 Fixed lease income $ 140,140 $ 133,180 Variable lease income 11,192 9,929 Total lease income $ 151,332 $ 143,109
Future Minimum Annual Rental Payments Receivable Under Residential and Commercial Leases	Future minimum annual rental payments we will receive under commercial leases, excluding such extension options, are as follows as of December 31, 2020 (in thousands): 2021 $ 10,866 2022 9,047 2023 5,761 2024 3,664 2025 2,551 Thereafter 1,315 Total $ 33,204
Minimum Annual Rental Payments Under Operating and Financing Leases	Minimum annual rental payments under these operating and financing leases, reconciled to the lease liabilities in our consolidated balance sheets, are as follows (in thousands): Sublease Income Operating Lease Future Minimum Rent Financing Leases Future Minimum Payments 2021 $ 1,380 $ 1,472 $ 1,200 2022 1,393 1,841 1,600 2023 1,403 1,871 2,000 2024 1,413 1,900 3,000 2025 1,423 1,930 3,500 Thereafter 4,959 6,814 1,151,782 Total $ 11,971 $ 15,828 $ 1,163,082 Less: Discount (2,113 ) (1,076,301 ) Total lease liabilities $ 13,715 $ 86,781

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Variable Interest Entities	The details of our consolidated and unconsolidated VIEs are summarized in the table below as of December 31, 2020 and 2019 (in thousands, except for VIE count). December 31, 2020 December 31, 2019 Consolidated Unconsolidated Consolidated Unconsolidated Count of VIEs 2 6 1 5 Assets: Real estate, net $ 310,552 $ — $ 299,387 $ — Mezzanine investment — 307,362 — 280,258 Right-of-use lease assets 92,709 — — — Unconsolidated real estate partnerships — 12,829 — 12,741 Other assets 16,949 12,500 14,645 — Liabilities: Notes Payable to AIR — — 66,295 — Deferred tax liability 133,842 — 143,934 — Accrued liabilities and other 7,106 — 8,873 — Lease liabilities 86,781 — — —

Mezzanine Investment (Tables)

Mezzanine Investment (Tables) - Parkmerced Investment [Member]	12 Months Ended
	Dec. 31, 2020
Schedule of Condensed Balance Sheet	The following table provides summarized balance sheet information of the Parkmerced Apartments as of December 31, 2019 (in thousands): December 31, 2019 Assets: Real estate, net $ 580,242 Cash and cash equivalents 25,078 Restricted cash 917 Other assets 22,510 Liabilities and equity: Notes payable, net 1,545,587 Other liabilities 15,149 Deficit $ (931,989 )
Schedule of Condensed Income Statement	The following table provides a summarized statement of operations information of the Parkmerced Apartments from the date of our investment, November 26, 2019, through December 31, 2019 (in thousands): REVENUES: Rental and other property revenues $ 10,089 OPERATING EXPENSES: Property operating expenses 4,365 Depreciation and amortization 2,116 General and administrative expenses 1,250 Total operating expenses 7,731 Interest expense (9,657 ) Other income, net 2,920 Net loss $ (4,379 )
Schedule of Condensed Cash Flow Statement	The following table provides a summarized statement of cash flow information of the Parkmerced Apartments from the date of our investment, November 26, 2019, through December 31, 2019 (in thousands): CASH FLOWS FROM OPERATING ACTIVITIES: Net cash used in operating activities $ (12,869 ) CASH FLOWS FROM INVESTING ACTIVITIES: Purchases of improvements, furniture, fixtures, and equipment (986 ) Net cash used in investing activities $ (986 ) CASH FLOWS FROM FINANCING ACTIVITIES: Proceeds from mortgage note payable 1,500,000 Proceeds from mezzanine note payable 275,000 Payments of mortgage financing costs (146,250 ) Payment of interest rate swap (15,900 ) Repayment of mortgage note payable (450,000 ) Repayment of mezzanine notes payable (1,047,927 ) Distributions (98,777 ) Net cash provided by investing activities $ 16,146 NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH 2,291 CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD 23,704 CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT END OF PERIOD $ 25,995

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Summary of Non-Recourse Property Debt	The following table summarizes non-recourse property debt a s of December 31, 2020 and 2019 (in thousands): Outstanding Balance as of December 31, Latest Maturity Date Interest Rate Range Weighted-Average Interest Rate 2020 2019 Fixed-rate property debt November 22, 2032 1.00% to 4.08% 3.38% $ 394,510 $ 438,886 Variable-rate property debt December 31, 2023 1.34% 1.34% 55,000 55,000 Total non-recourse property debt $ 449,510 $ 493,886 Assumed debt fair value adjustment, net of accumulated amortization 1,850 2,153 Debt issuance costs, net of accumulated amortization (3,393 ) (3,401 ) Non-recourse property debt, net $ 447,967 $ 492,638
Scheduled Principal Amortization and Maturity Payments for Non-Recourse Property Debt	As of December 31, 2020, the scheduled principal amortization and maturity payments for the non-recourse property debt were as follows (in thousands): Amortization Maturities Total 2021 $ 8,648 $ — $ 8,648 2022 9,087 15,773 24,860 2023 9,144 55,000 64,144 2024 7,099 81,940 89,039 2025 7,361 — 7,361 Thereafter 17,363 238,095 255,458 Total $ 58,702 $ 390,808 $ 449,510

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Components of Deferred tax Liabilities and Assets	Significant components of our deferred tax liabilities and assets are as follows (in thousands): December 31, 2020 2019 Deferred tax liabilities: Real estate and real estate partnership basis differences $ 132,599 $ 148,842 Deferred tax assets: Management contracts and other 999 615 Net operating, capital, and other loss carryforwards 40 — Net deferred tax liability $ 131,560 $ 148,227
Components of Income Tax Benefit or Expense	Significant components of the income tax benefit (expense) are as follows and are classified within income tax benefit (expense) in our consolidated statements of operations for the years ended December 31, 2020, 2019, and 2018 (in thousands): 2020 2019 2018 Current: Federal $ 857 $ 1,313 $ — State 660 536 284 Total current 1,517 1,849 284 Deferred: Federal (10,470 ) (4,658 ) 16 State (1,196 ) (492 ) (39 ) Total deferred (11,666 ) (5,150 ) (23 ) Total income tax (benefit) expense $ (10,149 ) $ (3,301 ) $ 261
Reconciliation of Income Tax Attributable to Operations	The reconciliation of income tax attributable to operations computed at the United States statutory rate to income tax benefit (expense) for the years ended December 31, 2020, 2019, and 2018 is shown below (in thousands): 2020 2019 2018 Amount Percent Amount Percent Amount Percent Tax (benefit) expense at United States statutory rates on consolidated income or loss subject to tax $ (5,361 ) 21.0 % $ (1,582 ) 21.0 % $ 16 21.0 % US branch profits tax on earnings of foreign subsidiary (4,195 ) 16.4 % (1,779 ) 23.6 % — — State income tax, net of federal (benefit) expense (536 ) 2.1 % 34 (0.5 %) 245 326.6 % Effects of permanent differences 1 (0.0 %) — — — — Other (58 ) 0.2 % 26 (0.3 %) — — Total income tax (benefit) expense $ (10,149 ) 39.7 % $ (3,301 ) 43.8 % $ 261 347.6 %
Schedule of Dividends Per Share Held	For the years ended December 31, 2020, 2019 and 2018, tax attributes of dividends per share held for the entire year were estimated to be as follows (unaudited): 2020 2019 2018 Amount Percent Amount Percent Amount Percent Ordinary income $ 3.17 6.7 % $ 0.66 20.6 % $ 0.51 33.5 % Capital gains 19.43 40.9 % 1.29 40.4 % 0.93 61.2 % Qualified dividends 0.62 1.3 % 0.66 20.7 % — 0 % Unrecaptured § 1250 gain 8.80 18.5 % 0.58 18.3 % 0.08 5.4 % Return of capital 15.48 32.6 % — — — — Balance at December 31 $ 47.50 100 % $ 3.19 100 % $ 1.52 100 %
Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending balance of our unrecognized tax benefits is presented below and is included in accrued liabilities and other in the consolidated balance sheets (in thousands): December 31, 2020 2019 Balance at January 1 $ — $ — Liability assumed at Separation 6,889 — Additions based on tax positions in prior years 187 — Balance at December 31 $ 7,076 $ —

Earnings per Share and per Un_2

Earnings per Share and per Unit (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Reconciliations of Numerator and Denominator in Calculations of Basic and Diluted Earnings per Share and per Unit	Reconciliations of the numerator and denominator in the calculations of basic and diluted earnings per share and per unit for the years ended December 31, 2020, 2019, and 2018 are as follows (in thousands, except per share and per unit data): Year Ended December 31, 2020 Income (Numerator) Shares (Denominator) Per Share Amount Basic and Diluted Earnings per Share: Net loss attributable to Aimco common stockholders $ (5,041 ) 148,569 $ (0.03 ) Year Ended December 31, 2019 Income (Numerator) Shares (Denominator) Per Share Amount Basic and Diluted Earnings per Share: Net income attributable to Aimco common stockholders $ 304 148,549 $ — Diluted Earnings per Share: Effect of dilutive securities — 20 — Net income attributable to Aimco common stockholders $ 304 148,569 $ — Year Ended December 31, 2018 Income (Numerator) Shares (Denominator) Per Share Amount Basic and Diluted Earnings per Share: Net income attributable to Aimco common stockholders $ 3,243 148,549 $ 0.02 Diluted Earnings per Share: Effect of dilutive securities — 20 — Net income attributable to Aimco common stockholders $ 3,243 148,569 $ 0.02 Year Ended December 31, 2020 Income (Numerator) Shares (Denominator) Per Unit Amount Basic and Diluted Earnings per unit: Net loss attributable to Aimco Operating Partnership's common unitholders $ (5,310 ) 156,500 $ (0.03 ) Year Ended December 31, 2019 Income (Numerator) Shares (Denominator) Per Unit Amount Basic and Diluted Earnings per unit: Net income attributable to Aimco Operating Partnership's common unitholders $ 319 156,480 $ — Diluted Earnings per unit: Effect of dilutive securities — 20 — Net income attributable to Aimco Operating Partnership's common unitholders $ 319 156,500 $ — Year Ended December 31, 2018 Income (Numerator) Shares (Denominator) Per Unit Amount Basic and Diluted Earnings per unit: Net income attributable to Aimco Operating Partnership's common unitholders $ 3,416 156,480 $ 0.02 Diluted Earnings per unit: Effect of dilutive securities — 20 — Net income attributable to Aimco Operating Partnership's common unitholders $ 3,416 156,500 $ 0.02

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2020
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Total Compensation Cost Recognized for Share-Based Awards	For the year ended December 31, 2020, total compensation cost recognized for share-based awards was (in thousands): 2020 (4) Share-based compensation expense (1) $ 1,070 Capitalized share-based compensation (2) 138 Total share-based compensation (3) $ 1,208 (1) Amounts are recorded in general and administrative expenses in our consolidated statements of operations. (2) Amounts are recorded in buildings and improvements on the consolidated balance sheets. (3) Amounts are recorded in additional paid-in capital and common noncontrolling interests in the Aimco Operating Partnership on the Aimco consolidated balance sheets, and in general partner and special limited partner and limited partners on the Aimco Operating Partnership consolidated balance sheets. (4) Amounts include share-based compensation costs allocated by Aimco Predecessor of $1.2 million.
Summary of Compensation Cost Not Yet Recognized for Share-Based Awards	We had Time-Based Stock Options, Time-Based Restricted Stock, TSR Stock Options, TSR Restricted Stock, TSR LTIP I units and TSR LTIP II units outstanding as of December 31, 2020. The following table summarizes the unvested or outstanding shares issued to employees of Aimco and AIR, and are potentially dilutive to Aimco and Aimco Operating Partnership as of December 31, 2020. Unvested Compensation Unvested shares Not Yet Recognized (2) Awards Aimco AIR (in thousands) Time-Based Stock Options (Outstanding shares) — 238,530 $ — TSR Stock Options (Outstanding shares) — 589,323 — Time-Based Restricted Stock Awards 21,473 73,190 608 TSR Restricted Stock Awards (1) 33,912 188,936 393 TSR LTIP I units 22,911 112,739 439 TSR LTIP II units 8,334 1,104,008 50 Total awards 86,630 2,306,726 $ 1,490 (1) The unvested awards are based on the target performance payout. (2) Unvested compensation not yet recognized represents Aimco’s compensation cost for Aimco employees. Compensation costs related to shares issued to AIR employees is recognized by AIR.

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Summary of fair value of interest rate option and investments in IQHQ and RETV ventures	The following table summarizes the fair value of our interest rate option and our investment in RET Ventures as of December 31, 2020 and 2019 (in thousands): As of December 31, 2020 As of December 31, 2019 Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Interest rate option $ 13,315 $ — $ 13,315 $ — $ — $ — $ — $ — Investment in RET Ventures (1) 2,293 — — — 752 — — — (1) Investments measured at fair value using the NAV practical expedient are not classified in the fair value hierarchy.
Summary of Carrying Value and Fair Value of Non-recourse Property Debt	The following table summarizes carrying value and fair value of our non-recourse property debt as of December 31, 2020 and 2019 (in thousands): As of December 31, 2020 2019 Carrying Value Fair Value Carrying Value Fair Value Non-recourse property debt $ 449,510 $ 467,010 $ 493,886 $ 499,841

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2020
Segment Reporting [Abstract]
Summary of Information for Reportable Segments	The following tables present the revenues, proportionate property net operating income, and income before income tax benefit (expense) of our segments on a proportionate basis, excluding amounts related to our proportionate share of four apartment communities with 142 apartment homes that we neither managed nor consolidated, for the years ended December 31, 2020, 2019, and 2018 (in thousands): Development and Redevelopment Operating Portfolio Other Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments Consolidated Year ended December 31, 2020: Rental and other property revenues $ 1,515 $ 130,689 $ 12,986 $ 6,196 $ 65 $ 151,451 Property operating expenses 981 43,891 4,148 5,702 6,792 61,514 Other operating expenses not allocated to segments (2) — — — — 104,294 104,294 Total operating expenses 981 43,891 4,148 5,702 111,086 165,808 Proportionate property net operating income 534 86,798 8,838 494 (111,021 ) (14,357 ) Other items included in loss before income tax benefit (3) — — — — (1,563 ) (1,563 ) Loss before income tax benefit $ 534 $ 86,798 $ 8,838 $ 494 $ (112,584 ) $ (15,920 ) Development and Redevelopment Operating Portfolio Other Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments Consolidated Year ended December 31, 2019: Rental and other property revenues $ — $ 131,346 $ 6,888 $ 5,458 $ — $ 143,692 Property operating expenses — 42,962 1,931 5,202 7,446 57,541 Other operating expenses not allocated to segments (2) — — — — 71,092 71,092 Total operating expenses — 42,962 1,931 5,202 78,538 128,633 Proportionate property net operating income — 88,384 4,957 256 (78,538 ) 15,059 Other items included in loss before income tax benefit (3) — — — — (18,247 ) (18,247 ) Loss before income tax benefit $ — $ 88,384 $ 4,957 $ 256 $ (96,785 ) $ (3,188 ) Development and Redevelopment Operating Portfolio Other Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments Consolidated Year ended December 31, 2018: Rental and other property revenues $ — $ 127,368 $ — $ 4,795 $ — $ 132,163 Property operating expenses — 41,778 — 4,795 6,979 53,552 Other operating expenses not allocated to segments (2) — — — — 55,141 55,141 Total operating expenses — 41,778 — 4,795 62,120 108,693 Proportionate property net operating income — 85,590 — — (62,120 ) 23,470 Other items included in income before income tax expense (3) — — — — (19,798 ) (19,798 ) Income before income tax expense $ — $ 85,590 $ — $ — $ (81,918 ) $ 3,672 (1) Represents adjustments for the redeemable noncontrolling interests in consolidated real estate partnership ’s share of the results of consolidated communities in our segment s , which are included in the related co nsolidated amounts, but excluded from proportionate property net operating income for our segment evaluation. Also includes the reclassification of utility reimbursements from revenues to property operating expenses for the purpose of evaluating segment results. Utility reimbursements are included in rental and other property revenues i n our co nsolidated statements of operations prepared in accordance with GAAP. (2) Other operating expenses not allocated to segments consists of depreciation and amortization, general and administrative expense, and other operating expenses which may include provision for real estate impairment loss, which are not included in our measure of segment performance. (3) Other items included in income before income tax benefit (expense) consists primarily of interest expense for the years ended December 31, 2020, 2019, and 2018, and mezzanine investment income, net, for the year ended December 31, 2020 and 2019.
Schedule of Net Real Estate and Non-Recourse Property Debt, Net, by Segment	Our properties in the Development and redevelopment segment were not acquired until the year ended December 31, 2020 and therefore, the segment had no assets for the year ended December 31, 2019. Net real estate and non-recourse property debt, net, of our segments as of December 31, 2020 and 2019 were as follows (in thousands): Development and Redevelopment Operating Other Total As of December 31, 2020: Buildings and improvements $ 61,813 $ 772,786 $ 160,517 $ 995,116 Land 56,676 298,459 150,018 505,153 Total real estate 118,489 1,071,245 310,535 1,500,269 Accumulated depreciation (447 ) (469,873 ) (24,690 ) (495,010 ) Net real estate $ 118,042 $ 601,372 $ 285,845 $ 1,005,259 Non-recourse property debt, net $ — $ 447,967 $ — $ 447,967 Development and Redevelopment Operating Portfolio Other Total As of December 31, 2019: Buildings and improvements $ — $ 779,513 $ 158,019 $ 937,532 Land — 298,458 149,422 447,880 Total real estate — 1,077,971 307,441 1,385,412 Accumulated depreciation — (441,390 ) (8,054 ) (449,444 ) Net real estate $ — $ 636,581 $ 299,387 $ 935,968 Non-recourse property debt, net $ — $ 492,638 $ — $ 492,638

Summarized Consolidated Quart_2

Summarized Consolidated Quarterly Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Summarized Unaudited Consolidated Quarterly Information	Aimco’s and Aimco Operating Partnership’s summarized consolidated quarterly financial information (unaudited) for the years ended December 31, 2020 and 2019, is provided below (in thousands): In the fourth quarter 2020, we recorded an impairment charge of $15.9 million. See Note 2 for further details. Aimco Year ended December 31, 2020 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenues $ 38,309 $ 37,165 $ 37,328 $ 38,649 Net income (loss) 3,785 3,883 1,996 (15,435 ) Net income (loss) attributable to Aimco common stockholders 3,897 3,994 2,118 (15,050 ) Earnings (loss) per share - basic and diluted $ 0.03 $ 0.03 $ 0.01 $ (0.10 ) Aimco year ended December 31, 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenues $ 35,789 $ 31,889 $ 37,813 $ 38,201 Net income (loss) 1,310 1,178 (1,107 ) (1,268 ) Net income (loss) attributable to Aimco common stockholders 1,322 1,178 (958 ) (1,238 ) Earnings (loss) attributable to Aimco per common share - basic $ 0.01 $ 0.01 $ (0.01 ) $ (0.01 ) Earnings (loss) attributable to Aimco per common share - diluted $ 0.01 $ 0.01 $ (0.01 ) $ (0.01 ) Aimco OP L.P. Year ended December 31, 2020 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenues $ 38,309 $ 37,165 $ 37,328 $ 38,649 Net income (loss) 3,785 3,883 1,996 (15,435 ) Net income (loss) attributable to the Aimco Operating Partnership's common unitholders 4,073 4,175 2,211 (15,769 ) Earnings (loss) attributable to the Aimco Operating Partnership per common unit - basic and diluted $ 0.03 $ 0.03 $ 0.01 $ (0.10 ) Aimco OP L.P. year ended December 31, 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Total revenues $ 35,789 $ 31,889 $ 37,813 $ 38,201 Net income (loss) 1,310 1,178 (1,107 ) (1,268 ) Net income (loss) attributable to the Aimco Operating Partnership's common unitholders 1,493 1,332 (1,102 ) (1,404 ) Earnings (loss) attributable to the Aimco Operating Partnership per common unit - basic $ 0.01 $ 0.01 $ (0.01 ) $ (0.01 ) Earnings (loss) attributable to the Aimco Operating Partnership per common unit - diluted $ 0.01 $ 0.01 $ (0.01 ) $ (0.01 )

Basis of Presentation and Org_2

Basis of Presentation and Organization (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)PropertyMulti_family_apartmentCommunityapartment_home	Dec. 31, 2019USD ($)
Organization [Line Items]
Notes payable | $	$ 534,127	$ 66,295
Number of units in real estate property | apartment_home	6,067
Continuing Operations [Member]
Organization [Line Items]
Number of consolidated real estate properties | Community	27
Number of units in real estate property | apartment_home	6,342
Aimco Post Separation [Member]
Organization [Line Items]
Number of consolidated real estate properties | Property	25
Aimco Operating Partnership [Member]
Organization [Line Items]
Percentage of the Aimco Operating Partnership common partnership units and equivalents owned by Aimco	93.20%
Percentage of economic interest in Aimco Operating Partnership owned by Aimco	94.80%
Percentage of Aimco Operating Partnership common partnership units and equivalents owned by other limited partners	6.80%
Apartment Income REIT [Member] | Aimco Post Separation [Member] | Multi-Family Communities Securing Note Payable [Member]
Organization [Line Items]
Number of consolidated real estate properties | Multi_family_apartment	16
Apartment Income REIT [Member] | Aimco Post Separation [Member] | Note Payable Secured by Multi-Family Communities [Member]
Organization [Line Items]
Notes payable | $	$ 534,100

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Weighted average ownership interest		5.40%	5.40%	5.40%
Interest costs capitalized		$ 1,000,000	$ 200,000	$ 300,000
Other direct and indirect costs capitalized		2,700,000	4,100,000	4,900,000
Gain (loss) on disposition of business		0	0	0
Impairment	$ 15,900,000	$ 15,860,000
Estimated useful life		15 years
Percentage of income tax on income from non-arms length transactions	100.00%	100.00%
Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		5 years
Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		30 years
Furniture, Fixtures and Equipment [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		5 years
Equipment [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life		5 years
Software License Agreement [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Impairment		$ 4,900,000	0	0
Sublease Office Space [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Impairment		$ 11,000,000	$ 0	$ 0

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Summary of Reconciliation of Redeemable Noncontrolling Interests in Real Estate Partnership (Details) - Real Estate Partnership [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Redeemable Noncontrolling Interest [Line Items]
Balance at December 31, 2019	$ 4,720
Net loss	(457)
Balance at December 31, 2020	$ 4,263

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid, net of amounts capitalized	$ 22,152	$ 17,748	$ 19,296
Cash paid for income taxes	9,216	1,773	284
Non-cash transactions associated with the acquisition of real estate:
Non-recourse property debt assumed in connection with the acquisition of real estate		66,779
Contributions from Aimco Predecessor	955
Contribution from noncontrolling interest in consolidated real estate partnerships	11,667
Deferred tax liability assumed in connection with the acquisition of real estate		148,809
Other non-cash transactions:
Accrued capital expenditures (at end of period)	1,641	$ 1,966	3,964
Non-recourse property debt assumed with collateral substitution			$ 72,296
Issuance of Notes Payable to AIR in connection with the Separation	534,127
Contributions from Aimco Predecessor, net	$ 131,447

Basis of Presentation and Sum_7

Basis of Presentation and Summary of Significant Accounting Policies - Summary of Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Intangible lease assets, net	$ 7,264	$ 13,380
Accounts receivable, net of allowances of $1,467 and $80 as of December 31, 2020 and 2019, respectively	2,660	2,313
Prepaid expenses and real estate taxes	10,493	2,991
Investment in IQHQ	12,500
Corporate fixed assets	12,860
Deferred costs, deposits, and other	17,557	2,354
Total other assets, net	$ 63,334	$ 21,038

Basis of Presentation and Sum_8

Basis of Presentation and Summary of Significant Accounting Policies - Summary of Other Assets (Parenthetical) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Accounts receivable, net of allowances	$ 1,467	$ 80

Basis of Presentation and Sum_9

Basis of Presentation and Summary of Significant Accounting Policies - Summary of Lease Intangible Assets and Liabilities, Net of Accumulated Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Less: accumulated amortization	$ (10,085)	$ (3,120)
Intangible lease assets, net	7,264	13,380
Below-market leases	4,886	4,219
Less: accumulated amortization	(2,366)	(633)
Intangible lease liabilities, net	2,520	3,586
In-Place Leases and Leasing Costs [Member]
Finite Lived Intangible Assets [Line Items]
In-place leases and leasing costs	17,203	16,355
Above Market Leases [Member]
Finite Lived Intangible Assets [Line Items]
In-place leases and leasing costs	$ 146	$ 145

Basis of Presentation and Su_10

Basis of Presentation and Summary of Significant Accounting Policies - Summary of Net Aggregate Amortization (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Finite Lived Intangible Assets [Line Items]
Below-market leases, 2020	$ 1,201
Below-market leases, 2021	676
Below-market leases, 2022	321
Below-market leases, 2023	176
Below-market leases, 2024	146
Intangible lease liabilities, net	2,520	$ 3,586
In-Place Leases and Leasing Costs [Member]
Finite Lived Intangible Assets [Line Items]
2021	3,938
2022	1,944
2023	830
2024	346
2025	206
Total future amortization	$ 7,264

Significant Transactions (Detai

Significant Transactions (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)apartment_home	Dec. 04, 2020ft²apartment_home
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment homes in apartment communities | apartment_home	6,067
Joint venture ownership percentage	81.00%
Promissory note issued	$ 85,000
Cash contribution	5,200
Investment	12,500
IQHQ [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Investment	12,500
Commitment purchase amount	$ 37,500
AIR [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Joint venture ownership percentage	19.00%
Cash contribution	$ 20,000
AIR [Member] | Joint Venture Transaction [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment homes in apartment communities | apartment_home		689
Area of retail space | ft²		100,000
Joint venture ownership percentage		90.00%
Upton Place JV [Member] | Minimum [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Percentage of apartment units leased	95.00%
Percentage of retail space leased	90.00%
Upton Place JV [Member] | Joint Venture Transaction [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Annual payments in exchange of economic rights	$ 1,150
Number of properties subject to ground leases	2
Ground lease period	99 years
Acquisition costs	$ 1,800
Upton Place JV [Member] | Developer [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Joint venture ownership percentage	10.00%
Noncontrolling interest in joint ventures	$ 11,700
Distribution liability in joint venture	$ 0

Significant Transactions - Summ

Significant Transactions - Summarized Information Regarding Acquisition (Details) - USD ($) $ in Thousands	Aug. 25, 2020	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Land		$ 505,153	$ 447,880
Buildings and improvements		995,116	937,532
Lease liabilities		(100,496)	0
Below market lease liabilities		$ (2,520)	$ (3,586)
Hamilton on the Bay [Member]
Business Acquisition [Line Items]
Purchase price	$ 115,394
Capitalized transaction costs	5,136
Total consideration	120,530
Land	56,649
Buildings and improvements	56,171
Right-of-use lease assets	92,787
Due from affiliates	705
Lease liabilities	(86,348)
Intangible assets	1,517
Below market lease liabilities	$ (951)

Significant Transactions - Su_2

Significant Transactions - Summarized Information Regarding Acquisition (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2020
In-Place Leases and Leasing Costs [Member]
Business Acquisition [Line Items]
Acquired intangible assets, weighted average useful life	6 months
Below Market Leases [Member]
Business Acquisition [Line Items]
Acquired intangible assets, weighted average useful life	7 months 6 days

Leases - Lease Income for Opera

Leases - Lease Income for Operating Leases (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Fixed lease income	$ 140,140	$ 133,180
Variable lease income	11,192	9,929
Total lease income	$ 151,332	$ 143,109

Leases - Future Minimum Annual

Leases - Future Minimum Annual Payments Receivable Under Residential and Commercial Leases (Details) - Commercial Real Estate [Member] $ in Thousands	Dec. 31, 2020USD ($)
Lessee Lease Description [Line Items]
2021	$ 10,866
2022	9,047
2023	5,761
2024	3,664
2025	2,551
Thereafter	1,315
Total	$ 33,204

Leases (Details Textual)

Leases (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 04, 2020
Lessee Lease Description [Line Items]
Financing lease, liability	$ 86,781
99 Year Ground Lease [Member]
Lessee Lease Description [Line Items]
Right-of-use lease assets		$ 92,800
Financing lease, liability		$ 86,300
Commercial lease [Member]
Lessee Lease Description [Line Items]
Lease, existence of option to extend	true
Weighted average remaining term	2 years 9 months 18 days
Residential Lease [Member]
Lessee Lease Description [Line Items]
Lease, existence of option to extend	false
Weighted average remaining term	1 year
Lease, option to extend	Generally, our residential leases do not provide extension options
Ground Lease [Member]
Lessee Lease Description [Line Items]
Weighted average remaining term	99 years
Operating lease, weighted average discount rate, percent	6.00%
Office Lease [Member]
Lessee Lease Description [Line Items]
Weighted average remaining term	8 years 4 months 24 days
Operating lease, weighted average discount rate, percent	3.20%

Leases - Minimum Annual Rental

Leases - Minimum Annual Rental Payments Under Operating and Financing Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Sublease Lease, Liability, Payment, Due [Abstract]
2021	$ 1,380
2022	1,393
2023	1,403
2024	1,413
2025	1,423
Thereafter	4,959
Total	11,971
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2021	1,472
2022	1,841
2023	1,871
2024	1,900
2025	1,930
Thereafter	6,814
Total	15,828
Less: Discount	(2,113)
Total lease liabilities	$ 13,715
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesAndOtherLiabilities
Finance Lease, Liability, Payment, Due [Abstract]
2021	$ 1,200
2022	1,600
2023	2,000
2024	3,000
2025	3,500
Thereafter	1,151,782
Total	1,163,082
Less: Discount	(1,076,301)
Financing lease, liability	$ 86,781

Transactions with AIR (Details

Transactions with AIR (Details Textual) - USD ($) $ in Thousands	Jan. 01, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 14, 2020
Related Party Transaction [Line Items]
Expenses from transactions with related party		$ 9,800	$ 9,500	$ 7,600
Due from Affiliates		4,333	0
Due to Affiliate		5,897	$ 0
Guarantee liability		$ 16,400
Estimated market discount rate		4.25%
Accrued Liabilities [Member]
Related Party Transaction [Line Items]
Guarantee liability		$ 16,300
AIR [Member]
Related Party Transaction [Line Items]
Discount on payment for early termination		5.00%
Notes payable principle amount					$ 534,100
Collateralized by portfolio of assets		$ 215,400
Interest rate on related party note payable		5.20%
Debt instrument maturity date		Jan. 31, 2024
Interest expense recognized		$ 1,300
Sub lease commencement date		Jan. 1, 2021
Sublease expiration date		May 31, 2029
Due from Affiliates		$ 5,900
Due to Affiliate		3,600
AIR [Member] | Indemnification Guarantee [Member]
Related Party Transaction [Line Items]
Maximum Indemnified, amount		$ 17,500
AIR [Member] | Related Party Property Management Agreement [Member]
Related Party Transaction [Line Items]
Property management/Property accounting agreements		We entered into several Property Management Agreements with AIR, pursuant to which AIR will provide us with certain property management/property accounting and related services for the majority of our operating properties, and we will pay AIR a property management fee of 3% of each respective property’s revenue collected and such other fees as may be mutually agreed for various other services. The initial term of each property management/property accounting agreement is one-year, with automatic one-year renewal periods, unless either party elects to terminate at any time upon delivery of 60 days’ prior written notice to the other party. Neither party is obligated to pay to the other party a termination fee or other penalty upon such termination.
Property management/ Property accounting fee, percent		3.00%
AIR [Member] | Subsequent Event [Member]
Related Party Transaction [Line Items]
Property management/ Property accounting fees	$ 200

Variable Interest Entities (Det

Variable Interest Entities (Details) $ in Thousands	Dec. 31, 2020USD ($)Entity	Dec. 31, 2019USD ($)Entity
Real estate, net	$ 1,005,259	$ 935,968
Mezzanine investment	307,362	280,258
Unconsolidated real estate partnerships	12,829	12,741
Other assets, net	63,334	21,038
Deferred tax liability	131,560	148,227
Accrued liabilities and other	57,091	$ 34,685
Financing lease, liability	$ 86,781
Consolidated Entities [Member]
Count of VIEs | Entity	2	1
Real estate, net	$ 310,552	$ 299,387
Right-of-use lease assets	92,709
Other assets, net	16,949	14,645
Notes Payable to AIR		66,295
Deferred tax liability	133,842	143,934
Accrued liabilities and other	7,106	$ 8,873
Financing lease, liability	$ 86,781
Unconsolidated Entities [Member]
Count of VIEs | Entity	6	5
Mezzanine investment	$ 307,362	$ 280,258
Unconsolidated real estate partnerships	12,829	$ 12,741
Other assets, net	$ 12,500

Variable Interest Entities (D_2

Variable Interest Entities (Details Textual) $ in Thousands	Dec. 31, 2020USD ($)apartment_home	Dec. 31, 2019USD ($)
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Mezzanine investment	$ 307,362	$ 280,258
San Diego Communities [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Number of apartment communities | apartment_home	4
Mezzanine investment	$ 12,800	$ 12,700
Parkmerced Investment [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Mezzanine investment	$ 307,400

Mezzanine Investment - Schedule

Mezzanine Investment - Schedule of Condensed Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Assets:
Real estate, net	$ 1,005,259	$ 935,968
Cash and cash equivalents	289,582	5,403
Restricted cash	9,153	4,717
Other assets, net	63,334	21,038
Liabilities and equity:
Notes payable, net	534,127	66,295
Deficit	$ (1,840,492)	(1,260,125)
Parkmerced Investment [Member]
Assets:
Real estate, net		580,242
Cash and cash equivalents		25,078
Restricted cash		917
Other assets, net		22,510
Liabilities and equity:
Notes payable, net		1,545,587
Other liabilities		15,149
Deficit		$ (931,989)

Mezzanine Investment - Schedu_2

Mezzanine Investment - Schedule of Condensed Income Statement (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
REVENUES:
Rental and other property revenues		$ 38,649	$ 37,328	$ 37,165	$ 38,309	$ 38,201	$ 37,813	$ 31,889	$ 35,789	$ 151,451	$ 143,692	$ 132,163
OPERATING EXPENSES:
Property operating expenses										61,514	57,541	53,552
Depreciation and amortization										77,965	64,030	49,375
General and administrative expenses										10,469	7,062	5,766
Total operating expenses										165,808	128,633	108,693
Interest expense										(27,512)	(18,598)	(19,643)
Net (loss) income		$ (15,435)	$ 1,996	$ 3,883	$ 3,785	$ (1,268)	$ (1,107)	$ 1,178	$ 1,310	$ (5,771)	$ 113	$ 3,411
Parkmerced Investment [Member]
REVENUES:
Rental and other property revenues	$ 10,089
OPERATING EXPENSES:
Property operating expenses	4,365
Depreciation and amortization	2,116
General and administrative expenses	1,250
Total operating expenses	7,731
Interest expense	(9,657)
Other income, net	2,920
Net (loss) income	$ (4,379)

Mezzanine Investment - Schedu_3

Mezzanine Investment - Schedule of Condensed Cash Flow Statement (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash used in operating activities		$ 47,846	$ 57,929	$ 53,486
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate		(107,908)	(95,895)
Net cash used in investing activities		(129,325)	(412,856)	(37,844)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Notes Payable to AIR			66,295
Net cash provided by (used in) financing activities		370,094	360,242	(15,923)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH		288,615	5,315	(281)
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD		10,120	4,805	5,086
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	$ 10,120	298,735	10,120	$ 4,805
Parkmerced Investment [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net cash used in operating activities	(12,869)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate	(986)
Net cash used in investing activities	(986)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Notes Payable to AIR	275,000
Payments of mortgage financing costs	(146,250)
Payment of interest rate swap	(15,900)
Repayment of mortgage note payable	(1,047,927)
Distributions	(98,777)
Net cash provided by (used in) financing activities	16,146
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	2,291
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD	23,704	$ 25,995
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	25,995		$ 25,995
Parkmerced Investment [Member] | Mortgages [Member]
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from Notes Payable to AIR	1,500,000
Repayment of mortgage note payable	$ (450,000)

Debt (Details Textual)

Debt (Details Textual)	Dec. 23, 2020USD ($)	Dec. 16, 2020USD ($)	Dec. 14, 2020USD ($)	Dec. 31, 2020USD ($)Property	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Debt instrument deemed rate		0.25%
Total debt issuance costs				$ 3,393,000	$ 3,401,000
Loans Payable				$ 215,400
Upton Place JV [Member]
Debt Instrument [Line Items]
Description of variable rate basis				Funds drawn upon will bear interest at a rate equal to one month Libor (“Libor”) plus 450 basis points subject to a minimum all-in per annum interest rate of 4.75%.
Total debt issuance costs				$ 7,500,000
Construction loan, term	99 years
Spread on variable interest rate	4.75%
Construction loan, description				The initial term of the construction loan is fifty-four months, beginning December 23, 2020. The Upton Place joint venture has the option to extend the term for two additional periods of one year each, subject to the satisfaction of certain events and covenant metrics.
Notes Payable to AIR [Member]
Debt Instrument [Line Items]
Notes payable principle amount			$ 534,100,000
Interest rate on related party note payable			5.20%
Quarterly periodic payment interest of notes payable description			accrued interest payable quarterly on January 1, April 1, July 1 and October 1, commencing on April 1, 2021
Note payable, maturity date			Jan. 31, 2024
Notes Payable to AIR [Member] | Interest Expense [Member]
Debt Instrument [Line Items]
Interest expense recognized				$ 1,300,000
Maximum [Member] | Upton Place JV [Member]
Debt Instrument [Line Items]
Construction loan availability	$ 174,200,000
London Interbank Offered Rate (LIBOR) [Member] | Upton Place JV [Member]
Debt Instrument [Line Items]
Spread on variable interest rate	4.50%
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member]
Debt Instrument [Line Items]
Spread on variable interest rate		0.25%
Base Rate [Member]
Debt Instrument [Line Items]
Spread on variable interest rate		0.50%
Description of variable rate basis				The base rate is defined as a fluctuating per annum rate of interest equal to the highest of (x) the overnight bank funding rate as reported by the Federal Reserve Bank of New York, plus 0.5%, (y) PNC Bank, National Association’s prime rate and (z) the daily LIBOR Rate plus 1.00%. If the LIBOR Rate determined under any referenced method would be less than .25%, such rate shall be deemed .25%.
Additional spread on variable interest rate		1
Swingline Loan Sub-Facility [Member]
Debt Instrument [Line Items]
Sub-facility outstanding balance				$ 0
Fixed Rate Property Debt | Pledged as Collateral
Debt Instrument [Line Items]
Number of real estate properties securing non-recourse debt | Property				11
Fixed Rate Property Debt | Minimum [Member]
Debt Instrument [Line Items]
Spread on variable interest rate				1.00%
Fixed Rate Property Debt | Maximum [Member]
Debt Instrument [Line Items]
Spread on variable interest rate				6.79%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility outstanding balance				$ 0
Letters of credit, outstanding amount				0
Total debt issuance costs				$ 1,900,000
Fixed charge coverage ratio				1.25
Minimum tangible net worth				$ 625,000,000
Leverage maximum				60.00%
Revolving Credit Facility [Member] | Loans Payable [Member] | Swingline Loan Sub-Facility [Member] | PNC Bank [Member]
Debt Instrument [Line Items]
Swingline loan sub-facility		$ 20,000,000
Revolving Credit Facility [Member] | Loans Payable [Member] | Swingline Loan Sub-Facility [Member] | PNC Bank [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Spread on variable interest rate		1.00%
Description of variable rate basis				base rate plus a margin of 1.00%.
Revolving Credit Facility [Member] | Secured Debt [Member] | PNC Bank [Member]
Debt Instrument [Line Items]
Secured credit facility		$ 150,000,000
Line of credit facility, maximum borrowing capacity		$ 300,000,000
Line of credit facility, expiration date		Dec. 31, 2023
Line of credit facility, option to extend expiration period, description				The credit facility expires on December 2023, but can be extended, at our option, by up to two twelve-month periods, subject to the satisfaction of certain events and covenant metrics.
Line of credit facility, interest rate description				(a) LIBOR plus a margin of 2.00% or (b) a base rate plus a margin of 1.00%.
Revolving Credit Facility [Member] | Secured Debt [Member] | PNC Bank [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Spread on variable interest rate		2.00%
Revolving Credit Facility [Member] | Secured Debt [Member] | PNC Bank [Member] | Base Rate [Member]
Debt Instrument [Line Items]
Spread on variable interest rate		1.00%
Letter of Credit [Member] | PNC Bank [Member]
Debt Instrument [Line Items]
Debt instrument, face amount		$ 30,000,000

Debt - Summary of Non-Recourse

Debt - Summary of Non-Recourse Property Loans Payable Related to Properties Classified as Held for Use (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Non-recourse property debt, net	$ 447,967	$ 492,638
Total non-recourse property debt	449,510	493,886
Assumed debt fair value adjustment, net of accumulated amortization	1,850	2,153
Debt issuance costs, net of accumulated amortization	(3,393)	(3,401)
Fixed-rate property debt [Member]
Debt Instrument [Line Items]
Non-recourse property debt, net	$ 394,510	438,886
Weighted-Average Interest Rate	3.38%
Fixed-rate property debt [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument maturity date	Nov. 22, 2032
Interest Rate	6.79%
Fixed-rate property debt [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest Rate	1.00%
Variable-rate property debt [Member]
Debt Instrument [Line Items]
Non-recourse property debt, net	$ 55,000	$ 55,000
Interest Rate	1.34%
Weighted-Average Interest Rate	1.34%
Variable-rate property debt [Member] | Maximum [Member]
Debt Instrument [Line Items]
Debt instrument maturity date	Dec. 31, 2023

Debt - Scheduled Principal Amor

Debt - Scheduled Principal Amortization and Maturity Payments for Non-Recourse Property Debt (Details) $ in Thousands	Dec. 31, 2020USD ($)
Amortization
2021	$ 8,648
2022	9,087
2023	9,144
2024	7,099
2025	7,361
Thereafter	17,363
Total	58,702
Maturities
2022	15,773
2023	55,000
2024	81,940
Thereafter	238,095
Total	390,808
Long Term Debt Amortization and Maturities
2021	8,648
2022	24,860
2023	64,144
2024	89,039
2025	7,361
Thereafter	255,458
Total	$ 449,510

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Liabilities and Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax liabilities:
Real estate and real estate partnership basis differences	$ 132,599	$ 148,842
Deferred tax assets:
Management contracts and other	999	615
Net operating, capital, and other loss carryforwards	40
Net deferred tax liabilities	$ 131,560	$ 148,227

Income Taxes (Details Textual)

Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes [Line Items]
Consolidated income (loss) subject to tax	$ (25,500)	$ (7,500)	$ (100)
Cash paid for income taxes	$ 9,216	1,773	$ 284
1001 Brickell Bay Drive [Member]
Income Taxes [Line Items]
Deferred tax liability		$ 148,800

Income Taxes - Components of In

Income Taxes - Components of Income Tax Benefit or Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
Federal	$ 857	$ 1,313	$ 0
State	660	536	284
Total current	1,517	1,849	284
Deferred:
Federal	(10,470)	(4,658)	16
State	(1,196)	(492)	(39)
Total deferred	(11,666)	(5,150)	(23)
Total income tax (benefit) expense	$ (10,149)	$ (3,301)	$ 261

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Income Tax Attributable to Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Amount
Tax (benefit) expense at United States statutory rates on consolidated income or loss subject to tax	$ (5,361)	$ (1,582)	$ 16
US branch profits tax on earnings of foreign subsidiary	(4,195)	(1,779)	0
State income tax, net of federal (benefit) expense	(536)	34	245
Effects of permanent differences	1	0	0
Other	(58)	26	0
Total income tax (benefit) expense	$ (10,149)	$ (3,301)	$ 261
Percent
Tax (benefit) expense at United States statutory rates on consolidated income or loss subject to tax	21.00%	21.00%	21.00%
US branch profits tax on earnings of foreign subsidiary	16.40%	23.60%	0.00%
State income tax, net of federal (benefit) expense	2.10%	(0.50%)	326.60%
Effects of permanent differences	0.00%	0.00%	0.00%
Other	0.20%	(0.30%)	0.00%
Total income tax (benefit) expense	39.70%	43.80%	347.60%

Income Taxes - Schedule of Divi

Income Taxes - Schedule of Dividends Per Share Held (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividends, Common Stock [Abstract]
Ordinary income	$ 3.17	$ 0.66	$ 0.51
Capital gains	19.43	1.29	0.93
Qualified dividends	0.62	0.66
Unrecaptured § 1250 gain	8.80	0.58	0.08
Return of capital	15.48
Total	$ 47.50	$ 3.19	$ 1.52
Dividends Common Stock Percentage [Abstract]
Ordinary income	6.70%	20.60%	33.50%
Capital gains	40.90%	40.40%	61.20%
Qualified dividends	1.30%	20.70%	0.00%
Unrecaptured § 1250 gain	18.50%	18.30%	5.40%
Return of capital	32.60%
Total	100.00%	100.00%	100.00%

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Income Tax Disclosure [Abstract]
Liability assumed at Separation	$ 6,889
Additions based on tax positions in prior years	187
Balance at December 31	$ 7,076

Aimco Equity (Details Textual)

Aimco Equity (Details Textual) - shares	12 Months Ended
	Dec. 31, 2020	Dec. 14, 2020	Dec. 31, 2019
Equity [Abstract]
Limited Liability Company or Limited Partnership, Equity Activities and Description	On December 15, 2020, we completed the previously announced separation of our business into two, separate and distinct, publicly traded companies, Aimco and AIR. The Separation was effected by way of a pro rata distribution, in which stockholders of Aimco received one share of Class A common stock of AIR for every one share of Class A common stock of Aimco held as of the close of business on December 5, 2020. AIR Operating Partnership also completed a pro rata distribution of all of the outstanding common limited partnership units of Aimco Operating Partnership to holders of AIR Operating Partnership common limited partnership units and AIR Operating Partnership Class I High Performance partnership units as of the close of business on December 5, 2020.
Common Stock, shares issued (in shares)	149,036,263	510,587,500	0

Partners' Capital - Narrative (

Partners' Capital - Narrative (Details)	Dec. 15, 2020shares
AIMCO PROPERTIES, L.P. [Member]
Related Party Transaction [Line Items]
Allotment Through Pro Rata Distribution	1

Earnings per Share and per Un_3

Earnings per Share and per Unit - Reconciliations of Numerator and Denominator in Calculations of Basic and Diluted Earnings per Share and per Unit (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Basic and Diluted Earnings per Share:
Net income attributable to Aimco Predecessor, net									$ (5,041)	$ 304	$ 3,243
Diluted Earnings per Share:
Net income attributable to Aimco common stockholders	$ (15,050)	$ 2,118	$ 3,994	$ 3,897	$ (1,238)	$ (958)	$ 1,178	$ 1,322	$ (5,041)	$ 304	$ 3,243
Basic weighted-average Common Stock outstanding									148,569	148,569	148,569
Basic weighted-average Common Stock outstanding, Gross										148,549	148,549
Dilutive share equivalents outstanding										20	20
Basic weighted-average Common Stock outstanding									148,569	148,569	148,569
Net (loss) income per common share – basic					$ (0.01)	$ (0.01)	$ 0.01	$ 0.01	$ (0.03)	$ 0	$ 0.02
Earnings per share – basic and diluted	$ (0.10)	$ 0.01	$ 0.03	$ 0.03
Aimco OP L.P. [Member]
Diluted Earnings per Share:
Basic weighted-average Common Stock outstanding									156,500	156,500	156,500
Basic weighted-average Common Stock outstanding, Gross										156,480	156,480
Dilutive share equivalents outstanding										20	20
Basic weighted-average Common Stock outstanding									156,500	156,500	156,500
Earnings per share – basic and diluted									$ (0.03)		$ 0.02
Net loss attributable to Aimco Operating Partnership's common unitholders									$ (5,310)	$ 319	$ 3,416

Share-Based Compensation (Detai

Share-Based Compensation (Details Textual) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unvested compensation cost not yet recognized for options and restricted stock awards | $	$ 1.5
Weighted average period over which unvested compensation cost expected to be recognized	1 year 6 months
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest period	4 years
Employee Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest period	4 years
Term of stock options	10 years
TSR Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
TSR restricted shares performance measurement period	3 years
Term of stock options	10 years
TSR Stock Awards [Member] | NAREIT Apartment Index [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted percentage of index used to compare to TSR	60.00%
TSR Stock Awards [Member] | MSCI US REIT Index [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted percentage of index used to compare to TSR	40.00%
TSR LTIP Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage, TSR restricted stock	50.00%
2020 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available to be granted under plan (in shares) | shares	29.8

Share-Based Compensation - Tota

Share-Based Compensation - Total Compensation Cost Recognized for Share-based Awards (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based compensation expense	$ 1,070
Capitalized share-based compensation	138
Total share-based compensation	$ 1,208

Share-Based Compensation - To_2

Share-Based Compensation - Total Compensation Cost Recognized for Share-based Awards (Parenthetical) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)
Amount share-based compensation	$ 1,208
AIR Predecessor Capital [Member]
Amount share-based compensation	$ 1,200

Share-Based Compensation - Comp

Share-Based Compensation - Compensation Cost Not Yet Recognized for Share-based Awards (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total awards unvested shares	86,630
Total awards unvested shares | $	$ 1,490
AIR [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total awards unvested shares	2,306,726
Employee Stock Option [Member] | AIR [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	238,530
TSR Stock Awards [Member] | AIR [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	589,323
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	21,473
Unvested shares | $	$ 608
Restricted Stock [Member] | AIR [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	73,190
TSR Restricted Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	33,912
Unvested shares | $	$ 393
TSR Restricted Stock Awards [Member] | AIR [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	188,936
TSR LTIP I Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	22,911
Unvested shares | $	$ 439
TSR LTIP I Units [Member] | AIR [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	112,739
TSR LTIP II Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	8,334
Unvested shares | $	$ 50
TSR LTIP II Units [Member] | AIR [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested shares	1,104,008

Fair Value Measurements (Detail

Fair Value Measurements (Details Textual) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
		Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative, description of terms			We receive a cash settlement in the future if the prevailing interest rate is higher than the 1.68% strike price. The amount of future cash settlement is capped if the prevailing interest rate exceeds 2.78%. Alternatively, if interest rates were to decrease below the specified strike price, we would not receive a cash settlement.
Investment		$ 12,500	$ 12,500
Impairment		15,900	15,860
Fair Value Measurements Recurring [Member] | RET Ventures [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment	[1]	$ 2,293	2,293	$ 752
Fair Value Measurements Non-Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impairment			15,900	$ 0
Interest Rate Option [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Payments for purchase of swaption			$ 12,100
Derivative strike rate		1.68%	1.68%
Derivative strike rate for limited settlement		2.78%	2.78%
[1]	Investments measured at fair value using the NAV practical expedient are not classified in the fair value hierarchy.

Fair Value Measurements - Summa

Fair Value Measurements - Summary of fair value of interest rate option and investments in IQHQ and RETV ventures (Details) - USD ($) $ in Thousands		Dec. 31, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment		$ 12,500
Fair Value Measurements Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate option		13,315	$ 0
Fair Value Measurements Recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate option		0	0
Fair Value Measurements Recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate option		13,315	0
Fair Value Measurements Recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Interest rate option		0	0
Fair Value Measurements Recurring [Member] | RET Ventures [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment	[1]	2,293	752
Fair Value Measurements Recurring [Member] | RET Ventures [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment	[1]	0	0
Fair Value Measurements Recurring [Member] | RET Ventures [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment	[1]	0	0
Fair Value Measurements Recurring [Member] | RET Ventures [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Investment	[1]	$ 0	$ 0
[1]	Investments measured at fair value using the NAV practical expedient are not classified in the fair value hierarchy.

Fair Value Measurements - Sum_2

Fair Value Measurements - Summary of Carrying Value and Fair Value of Non-recourse Property Debt (Details) - Non-recourse property debt [Member] - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Carrying Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Non-recourse property debt	$ 449,510	$ 493,886
Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Non-recourse property debt	$ 467,010	$ 499,841

Commitments and Contingencies (

Commitments and Contingencies (Details Textual) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
Commitments related to development, redevelopment and capital improvement activities [Member]
Long-term Purchase Commitment [Line Items]
Commitments related to capital spending activities	$ 3.2
Time Period of Long-term Purchase Commitment	12 months
Commitments related to operations [Member] | IQHQ [Member]
Long-term Purchase Commitment [Line Items]
Commitment for additional funding to IQHQ	$ 37.5
Commitments related to operations [Member] | RET Ventures [Member]
Long-term Purchase Commitment [Line Items]
Commitment for additional funding to IQHQ	$ 1.1
Commitments related to operations [Member] | Maximum [Member]
Long-term Purchase Commitment [Line Items]
Time Period of Long-term Purchase Commitment	1 year
Bearing environmental liabilities	$ 17.5

Business Segments (Details Text

Business Segments (Details Textual)	12 Months Ended
	Dec. 31, 2020Propertyapartment_homeSegmentapartment_buildingoffice_building
Business Segments (Textual) [Abstract]
Number of reportable segments | Segment	3
Number of units in real estate property | apartment_home	6,067
Wholly And Partially Owned Consolidated Properties [Member] | Operating Portfolio Segment [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	24
Number of units in real estate property | apartment_building	6,067
Wholly And Partially Owned Consolidated Properties [Member] | Other [Member] | Office Building [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | office_building	1
Unconsolidated Properties [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	4
Number of units in real estate property | apartment_building	142

Business Segments - Summary of

Business Segments - Summary of Information for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary information for the reportable segments
Rental and other property revenues	$ 38,649	$ 37,328	$ 37,165	$ 38,309	$ 38,201	$ 37,813	$ 31,889	$ 35,789	$ 151,451	$ 143,692	$ 132,163
Property operating expenses									61,514	57,541	53,552
Other operating expenses not allocated to segments									104,294	71,092	55,141
Total operating expenses									165,808	128,633	108,693
Proportionate property net operating income (loss)									(14,357)	15,059	23,470
Other items included in income (loss) before income tax benefit									(1,563)	(18,247)	(19,798)
(Loss) income before income tax benefit (expense)									(15,920)	(3,188)	3,672
Segment Reconciling Items [Member]
Summary information for the reportable segments
Rental and other property revenues									6,196	5,458	4,795
Property operating expenses									5,702	5,202	4,795
Total operating expenses									5,702	5,202	4,795
Proportionate property net operating income (loss)									494	256
(Loss) income before income tax benefit (expense)									494	256
Corporate Non-Segment [Member]
Summary information for the reportable segments
Rental and other property revenues									65
Property operating expenses									6,792	7,446	6,979
Other operating expenses not allocated to segments									104,294	71,092	55,141
Total operating expenses									111,086	78,538	62,120
Proportionate property net operating income (loss)									(111,021)	(78,538)	(62,120)
Other items included in income (loss) before income tax benefit									(1,563)	(18,247)	(19,798)
(Loss) income before income tax benefit (expense)									(112,584)	(96,785)	(81,918)
Development and Redevelopment [Member] | Operating Segments [Member]
Summary information for the reportable segments
Rental and other property revenues									1,515
Property operating expenses									981
Total operating expenses									981
Proportionate property net operating income (loss)									534
(Loss) income before income tax benefit (expense)									534
Operating Portfolio Segment [Member] | Operating Segments [Member]
Summary information for the reportable segments
Rental and other property revenues									130,689	131,346	127,368
Property operating expenses									43,891	42,962	41,778
Total operating expenses									43,891	42,962	41,778
Proportionate property net operating income (loss)									86,798	88,384	85,590
(Loss) income before income tax benefit (expense)									86,798	88,384	$ 85,590
Other [Member] | Operating Segments [Member]
Summary information for the reportable segments
Rental and other property revenues									12,986	6,888
Property operating expenses									4,148	1,931
Total operating expenses									4,148	1,931
Proportionate property net operating income (loss)									8,838	4,957
(Loss) income before income tax benefit (expense)									$ 8,838	$ 4,957

Business Segments - Schedule of

Business Segments - Schedule of Net Real Estate and Non-Recourse Property Debt, Net, by Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Buildings and improvements	$ 772,788
Land	505,153	$ 447,880
Total real estate	1,071,246
Accumulated depreciation	(469,876)
Net real estate	601,370
Operating Segments [Member]
Segment Reporting Information [Line Items]
Buildings and improvements	995,116	937,532
Land	505,153	447,880
Total real estate	1,500,269	1,385,412
Accumulated depreciation	(495,010)	(449,444)
Net real estate	1,005,259	935,968
Non-recourse property debt, net	447,967	492,638
Development and Redevelopment [Member]
Segment Reporting Information [Line Items]
Buildings and improvements	61,811
Total real estate	118,488
Accumulated depreciation	(446)
Net real estate	118,042
Development and Redevelopment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Buildings and improvements	61,813
Land	56,676
Total real estate	118,489
Accumulated depreciation	(447)
Net real estate	118,042
Operating Portfolio Segment [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Buildings and improvements	772,786	779,513
Land	298,459	298,458
Total real estate	1,071,245	1,077,971
Accumulated depreciation	(469,873)	(441,390)
Net real estate	601,372	636,581
Non-recourse property debt, net	447,967	492,638
Other [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Buildings and improvements	160,517	158,019
Land	150,018	149,422
Total real estate	310,535	307,441
Accumulated depreciation	(24,690)	(8,054)
Net real estate	$ 285,845	$ 299,387

Subsequent Events (Details Text

Subsequent Events (Details Textual) - USD ($) $ in Thousands	Jan. 01, 2021	Dec. 31, 2020	Dec. 31, 2019
Subsequent Event [Line Items]
Lease agreements description		According to the terms of the lease agreements, we have the option to complete the on-going development and redevelopment of such properties and their lease-ups. If we elect such options, following the successful completion of the contemplated development and redevelopments, AIR has the option (and not an obligation) to pay us an amount equal to the difference between the then-current fair market value of the properties and the initial fair market value of the properties at the time of lease inception, at a five percent discount thereto.
Fair Value Discount Rate		5.00%
Lease term		25 years
Payments for lease		$ 140,140	$ 133,180
Subsequent Event [Member]
Subsequent Event [Line Items]
Payments for lease	$ 2,100
Aggregate lease payments, total	$ 601,600
Lease commencement date	Jan. 1, 2021
Subsequent Event [Member] | Construction Contracts [Member]
Subsequent Event [Line Items]
Estimated lease obligations related to development and redevelopment spending	$ 62,400
Prism [Member]
Subsequent Event [Line Items]
Lease term		10 years

Summarized Consolidated Quart_3

Summarized Consolidated Quarterly Information (Unaudited) (Details Textual) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Impairment	$ 15,900	$ 15,860

Summarized Consolidated Quart_4

Summarized Consolidated Quarterly Information (Unaudited) - Summary of Unaudited Consolidated Quarterly Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Unaudited Quarterly Financial Information [Line Items]
Total revenues	$ 38,649	$ 37,328	$ 37,165	$ 38,309	$ 38,201	$ 37,813	$ 31,889	$ 35,789	$ 151,451	$ 143,692	$ 132,163
Net income (loss)	(15,435)	1,996	3,883	3,785	(1,268)	(1,107)	1,178	1,310	(5,771)	113	3,411
Net income attributable to Aimco common stockholders	$ (15,050)	$ 2,118	$ 3,994	$ 3,897	$ (1,238)	$ (958)	$ 1,178	$ 1,322	$ (5,041)	$ 304	$ 3,243
Earnings per share – basic and diluted	$ (0.10)	$ 0.01	$ 0.03	$ 0.03
Net (loss) income per common share – basic					$ (0.01)	$ (0.01)	$ 0.01	$ 0.01	$ (0.03)	$ 0	$ 0.02
Net (loss) income per common share – diluted					$ (0.01)	$ (0.01)	$ 0.01	$ 0.01	$ (0.03)	$ 0	$ 0.02
Aimco OP L.P. [Member]
Schedule Of Unaudited Quarterly Financial Information [Line Items]
Total revenues	$ 38,649	$ 37,328	$ 37,165	$ 38,309	$ 38,201	$ 37,813	$ 31,889	$ 35,789
Net income (loss)	(15,435)	1,996	3,883	3,785	(1,268)	(1,107)	1,178	1,310
Net income attributable to Aimco common stockholders	$ (15,769)	$ 2,211	$ 4,175	$ 4,073	$ (1,404)	$ (1,102)	$ 1,332	$ 1,493
Earnings per share – basic and diluted	$ (0.10)	$ 0.01	$ 0.03	$ 0.03
Net (loss) income per common share – basic					$ (0.01)	$ (0.01)	$ 0.01	$ 0.01
Net (loss) income per common share – diluted					$ (0.01)	$ (0.01)	$ 0.01	$ 0.01

Schedule III_ Real Estate and A

Schedule III: Real Estate and Accumulated Depreciation - Schedule of Real Estate and Accumulated Depreciation (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)apartment_home
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes in apartment communities | apartment_home	6,067
Initial Cost, Land	$ 298,458
Initial Cost, Buildings and Improvements	405,409
Costs Capitalized Subsequent to Consolidation	367,379
Land	298,458
Buildings and improvements	772,788
Total real estate	1,071,246
Accumulated Depreciation (AD)	(469,876)
Net real estate	601,370
Encumbrances	$ 449,510
Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes in apartment communities | apartment_home	6,342
Initial Cost, Land	$ 504,529
Initial Cost, Buildings and Improvements	614,371
Costs Capitalized Subsequent to Consolidation	381,368
Land	505,153
Buildings and improvements	995,116
Total real estate	1,500,269
Accumulated Depreciation (AD)	(495,010)
Net real estate	1,005,259
Encumbrances	$ 449,510
Royal Crest Estates [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Aug. 31, 2002
Location	Marlborough, MA
Year Built	1970
Number of apartment homes in apartment communities | apartment_home	473
Initial Cost, Land	$ 25,178
Initial Cost, Buildings and Improvements	28,786
Costs Capitalized Subsequent to Consolidation	16,040
Land	25,178
Buildings and improvements	44,826
Total real estate	70,004
Accumulated Depreciation (AD)	(32,266)
Net real estate	37,738
Encumbrances	$ 60,828
Stabilized [Member] | Royal Crest Estates [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Aug. 31, 2002
Location	Warwick, RI
Year Built	1972
Number of apartment homes in apartment communities | apartment_home	492
Initial Cost, Land	$ 22,433
Initial Cost, Buildings and Improvements	24,095
Costs Capitalized Subsequent to Consolidation	5,552
Land	22,433
Buildings and improvements	29,647
Total real estate	52,080
Accumulated Depreciation (AD)	(21,366)
Net real estate	30,714
Encumbrances	$ 0
Stabilized [Member] | St. George Villas [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Jan. 31, 2006
Location	St. George, SC
Year Built	1984
Number of apartment homes in apartment communities | apartment_home	40
Initial Cost, Land	$ 108
Initial Cost, Buildings and Improvements	1,024
Costs Capitalized Subsequent to Consolidation	423
Land	108
Buildings and improvements	1,447
Total real estate	1,555
Accumulated Depreciation (AD)	(1,330)
Net real estate	225
Encumbrances	$ 283
Stabilized [Member] | Waterford Village [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Aug. 31, 2002
Location	Bridgewater, MA
Year Built	1971
Number of apartment homes in apartment communities | apartment_home	588
Initial Cost, Land	$ 29,110
Initial Cost, Buildings and Improvements	28,101
Costs Capitalized Subsequent to Consolidation	11,511
Land	29,110
Buildings and improvements	39,612
Total real estate	68,722
Accumulated Depreciation (AD)	(31,341)
Net real estate	37,381
Encumbrances	$ 0
Stabilized [Member] | Wexford Village [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Aug. 31, 2002
Location	Worcester, MA
Year Built	1974
Number of apartment homes in apartment communities | apartment_home	264
Initial Cost, Land	$ 6,349
Initial Cost, Buildings and Improvements	17,939
Costs Capitalized Subsequent to Consolidation	5,039
Land	6,349
Buildings and improvements	22,978
Total real estate	29,327
Accumulated Depreciation (AD)	(15,007)
Net real estate	14,320
Encumbrances	$ 0
Stabilized [Member] | Yacht Club at Brickell [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Dec. 31, 2003
Location	Miami, FL
Year Built	1998
Number of apartment homes in apartment communities | apartment_home	357
Initial Cost, Land	$ 31,362
Initial Cost, Buildings and Improvements	32,214
Costs Capitalized Subsequent to Consolidation	18,583
Land	31,362
Buildings and improvements	50,797
Total real estate	82,159
Accumulated Depreciation (AD)	(22,022)
Net real estate	60,137
Encumbrances	$ 84,548
Stabilized [Member] | Bluffs at Pacifica, The [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Oct. 31, 2006
Location	Pacifica, CA
Year Built	1963
Number of apartment homes in apartment communities | apartment_home	64
Initial Cost, Land	$ 8,108
Initial Cost, Buildings and Improvements	4,132
Costs Capitalized Subsequent to Consolidation	16,952
Land	8,108
Buildings and improvements	21,084
Total real estate	29,192
Accumulated Depreciation (AD)	(11,964)
Net real estate	17,228
Encumbrances	$ 0
Separate Portfolio [Member] | 118-122 West 23rd Street [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Jun. 30, 2012
Location	New York, NY
Year Built	1987
Number of apartment homes in apartment communities | apartment_home	42
Initial Cost, Land	$ 14,985
Initial Cost, Buildings and Improvements	23,459
Costs Capitalized Subsequent to Consolidation	7,291
Land	14,985
Buildings and improvements	30,750
Total real estate	45,735
Accumulated Depreciation (AD)	(11,677)
Net real estate	34,058
Encumbrances	$ 16,523
Separate Portfolio [Member] | Royal Crest Estates [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Aug. 31, 2002
Location	Nashua, NH
Year Built	1970
Number of apartment homes in apartment communities | apartment_home	902
Initial Cost, Land	$ 68,230
Initial Cost, Buildings and Improvements	45,562
Costs Capitalized Subsequent to Consolidation	16,122
Land	68,230
Buildings and improvements	61,684
Total real estate	129,914
Accumulated Depreciation (AD)	(46,931)
Net real estate	82,983
Encumbrances	$ 88,446
Separate Portfolio [Member] | 1045 on the Park Apartments Homes [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Acquired	Jul. 31, 2013
Location	Atlanta, GA
Year Built	2012
Number of apartment homes in apartment communities | apartment_home	30
Initial Cost, Land	$ 2,793
Initial Cost, Buildings and Improvements	6,662
Costs Capitalized Subsequent to Consolidation	866
Land	2,793
Buildings and improvements	7,528
Total real estate	10,321
Accumulated Depreciation (AD)	(2,066)
Net real estate	8,255
Encumbrances	$ 0
Separate Portfolio [Member] | 2200 Grace [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Aug. 31, 2018
Location	Lombard, IL
Year Built	1971
Number of apartment homes in apartment communities | apartment_home	72
Initial Cost, Land	$ 642
Initial Cost, Buildings and Improvements	7,788
Costs Capitalized Subsequent to Consolidation	480
Land	642
Buildings and improvements	8,268
Total real estate	8,910
Accumulated Depreciation (AD)	(5,098)
Net real estate	3,812
Encumbrances	$ 7,311
Separate Portfolio [Member] | 173 E. 90th Street [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	May 31, 2004
Location	New York, NY
Year Built	1910
Number of apartment homes in apartment communities | apartment_home	72
Initial Cost, Land	$ 12,066
Initial Cost, Buildings and Improvements	4,535
Costs Capitalized Subsequent to Consolidation	8,910
Land	12,066
Buildings and improvements	13,445
Total real estate	25,511
Accumulated Depreciation (AD)	(5,389)
Net real estate	20,122
Encumbrances	$ 0
Separate Portfolio [Member] | 2900 on First Apartments [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Acquired	Oct. 31, 2008
Location	Seattle, WA
Year Built	1989
Number of apartment homes in apartment communities | apartment_home	135
Initial Cost, Land	$ 19,070
Initial Cost, Buildings and Improvements	17,518
Costs Capitalized Subsequent to Consolidation	33,767
Land	19,070
Buildings and improvements	51,285
Total real estate	70,355
Accumulated Depreciation (AD)	(30,596)
Net real estate	39,759
Encumbrances	$ 0
Separate Portfolio [Member] | 237-239 Ninth Avenue [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Mar. 31, 2005
Location	New York, NY
Year Built	1900
Number of apartment homes in apartment communities | apartment_home	36
Initial Cost, Land	$ 8,495
Initial Cost, Buildings and Improvements	1,866
Costs Capitalized Subsequent to Consolidation	3,010
Land	8,495
Buildings and improvements	4,876
Total real estate	13,371
Accumulated Depreciation (AD)	(3,331)
Net real estate	10,040
Encumbrances	$ 0
Separate Portfolio [Member] | Pathfinder Village [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Jan. 31, 2006
Location	Fremont, CA
Year Built	1973
Number of apartment homes in apartment communities | apartment_home	246
Initial Cost, Land	$ 19,595
Initial Cost, Buildings and Improvements	14,838
Costs Capitalized Subsequent to Consolidation	21,463
Land	19,595
Buildings and improvements	36,301
Total real estate	55,896
Accumulated Depreciation (AD)	(20,344)
Net real estate	35,552
Encumbrances	$ 55,000
Separate Portfolio [Member] | Plantation Gardens [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Oct. 31, 1999
Location	Plantation ,FL
Year Built	1971
Number of apartment homes in apartment communities | apartment_home	372
Initial Cost, Land	$ 3,773
Initial Cost, Buildings and Improvements	19,443
Costs Capitalized Subsequent to Consolidation	21,803
Land	3,773
Buildings and improvements	41,246
Total real estate	45,019
Accumulated Depreciation (AD)	(26,499)
Net real estate	18,520
Encumbrances	$ 31,719
Separate Portfolio [Member] | Willow Bend [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	May 31, 1998
Location	Rolling Meadows, IL
Year Built	1969
Number of apartment homes in apartment communities | apartment_home	328
Initial Cost, Land	$ 2,717
Initial Cost, Buildings and Improvements	15,437
Costs Capitalized Subsequent to Consolidation	19,975
Land	2,717
Buildings and improvements	35,412
Total real estate	38,129
Accumulated Depreciation (AD)	(26,224)
Net real estate	11,905
Encumbrances	$ 0
Separate Portfolio [Member] | Yorktown Apartments [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Dec. 31, 1999
Location	Lombard, IL
Year Built	1971
Number of apartment homes in apartment communities | apartment_home	292
Initial Cost, Land	$ 2,413
Initial Cost, Buildings and Improvements	10,374
Costs Capitalized Subsequent to Consolidation	51,981
Land	2,413
Buildings and improvements	62,355
Total real estate	64,768
Accumulated Depreciation (AD)	(35,453)
Net real estate	29,315
Encumbrances	$ 29,612
Separate Portfolio [Member] | Bank Lofts [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Apr. 30, 2001
Location	Denver, CO
Year Built	1920
Number of apartment homes in apartment communities | apartment_home	125
Initial Cost, Land	$ 3,525
Initial Cost, Buildings and Improvements	9,045
Costs Capitalized Subsequent to Consolidation	5,698
Land	3,525
Buildings and improvements	14,743
Total real estate	18,268
Accumulated Depreciation (AD)	(8,400)
Net real estate	9,868
Encumbrances	$ 0
Separate Portfolio [Member] | Cedar Rim [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Apr. 30, 2000
Location	Newcastle, WA
Year Built	1980
Number of apartment homes in apartment communities | apartment_home	104
Initial Cost, Land	$ 761
Initial Cost, Buildings and Improvements	5,218
Costs Capitalized Subsequent to Consolidation	14,706
Land	761
Buildings and improvements	19,924
Total real estate	20,685
Accumulated Depreciation (AD)	(15,201)
Net real estate	5,484
Encumbrances	$ 0
Separate Portfolio [Member] | Elm Creek [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Acquired	Dec. 31, 1997
Location	Elmhurst, IL
Year Built	1987
Number of apartment homes in apartment communities | apartment_home	400
Initial Cost, Land	$ 5,910
Initial Cost, Buildings and Improvements	30,830
Costs Capitalized Subsequent to Consolidation	31,941
Land	5,910
Buildings and improvements	62,771
Total real estate	68,681
Accumulated Depreciation (AD)	(37,480)
Net real estate	31,201
Encumbrances	$ 49,119
Separate Portfolio [Member] | Evanston Place [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Dec. 31, 1997
Location	Evanston, IL
Year Built	1990
Number of apartment homes in apartment communities | apartment_home	190
Initial Cost, Land	$ 3,232
Initial Cost, Buildings and Improvements	25,546
Costs Capitalized Subsequent to Consolidation	17,069
Land	3,232
Buildings and improvements	42,615
Total real estate	45,847
Accumulated Depreciation (AD)	(22,539)
Net real estate	23,308
Encumbrances	$ 0
Separate Portfolio [Member] | Hillmeade [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Acquired	Nov. 30, 1994
Location	Nashville, TN
Year Built	1986
Number of apartment homes in apartment communities | apartment_home	288
Initial Cost, Land	$ 2,872
Initial Cost, Buildings and Improvements	16,070
Costs Capitalized Subsequent to Consolidation	21,782
Land	2,872
Buildings and improvements	37,852
Total real estate	40,724
Accumulated Depreciation (AD)	(23,900)
Net real estate	16,824
Encumbrances	$ 26,121
Separate Portfolio [Member] | Hyde Park Tower [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Oct. 31, 2004
Location	Chicago, IL
Year Built	1990
Number of apartment homes in apartment communities | apartment_home	155
Initial Cost, Land	$ 4,731
Initial Cost, Buildings and Improvements	14,927
Costs Capitalized Subsequent to Consolidation	16,415
Land	4,731
Buildings and improvements	31,342
Total real estate	36,073
Accumulated Depreciation (AD)	(13,452)
Net real estate	22,621
Encumbrances	$ 0
Development and Redevelopment [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes in apartment communities | apartment_home	275
Initial Cost, Land	$ 56,649
Initial Cost, Buildings and Improvements	56,171
Costs Capitalized Subsequent to Consolidation	5,668
Land	56,677
Buildings and improvements	61,811
Total real estate	118,488
Accumulated Depreciation (AD)	(446)
Net real estate	118,042
Encumbrances	$ 0
Development and Redevelopment [Member] | Hamilton on the Bay [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Aug. 31, 2020
Location	Miami, FL
Year Built	1985
Number of apartment homes in apartment communities | apartment_home	275
Initial Cost, Land	$ 56,649
Initial Cost, Buildings and Improvements	34,891
Costs Capitalized Subsequent to Consolidation	2,242
Land	56,677
Buildings and improvements	37,105
Total real estate	93,782
Accumulated Depreciation (AD)	(446)
Net real estate	93,336
Encumbrances	$ 0
Development and Redevelopment [Member] | Upton Place [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Date Acquired	Dec. 31, 2020
Location	Washington, DC
Number of apartment homes in apartment communities | apartment_home	0
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	21,280
Costs Capitalized Subsequent to Consolidation	3,426
Land	0
Buildings and improvements	24,706
Total real estate	24,706
Accumulated Depreciation (AD)	0
Net real estate	24,706
Encumbrances	$ 0
Other [Member] | 1001 Brickell Bay Drive [Member] | Continuing Operations [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Acquired	Jul. 31, 2019
Location	Miami, FL
Year Built	1985
Number of apartment homes in apartment communities | apartment_home	0
Initial Cost, Land	$ 149,422
Initial Cost, Buildings and Improvements	152,791
Costs Capitalized Subsequent to Consolidation	8,321
Land	150,018
Buildings and improvements	160,517
Total real estate	310,535
Accumulated Depreciation (AD)	(24,688)
Net real estate	285,847
Encumbrances	$ 0

Schedule III_ Real Estate and_2

Schedule III: Real Estate and Accumulated Depreciation - Schedule of Real Estate and Accumulated Depreciation (Parenthetical) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Aggregate cost of land and depreciable property for federal income tax purposes	$ 1.2
Minimum [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Depreciable life for buildings and improvements	5 years
Maximum [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Depreciable life for buildings and improvements	30 years

Schedule III_ Real Estate and_3

Schedule III: Real Estate and Accumulated Depreciation - Summary Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Additions during the year:
Total portfolio balance at end of year	$ 1,071,246
Accumulated depreciation balance at end of year	469,876
Aimco Real Estate
Total portfolio
Total portfolio balance at beginning of year	1,385,412	$ 1,053,589	$ 1,029,066
Additions during the year:
Acquisitions	112,820	302,213
Capital additions	24,334	37,327	38,002
Write-offs of fully depreciated assets and other	(22,297)	(7,717)	(13,479)
Total portfolio balance at end of year	1,500,269	1,385,412	1,053,589
Accumulated depreciation balance at beginning of year	449,444	398,300	364,799
Depreciation	67,919	58,436	46,816
Write-offs of fully depreciated assets and other	(22,353)	(7,292)	(13,315)
Accumulated depreciation balance at end of year	$ 495,010	$ 449,444	$ 398,300