Apartment Investment and Management (AIV) 10-Q 2 Nov 20 2020 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 28, 2020
Document Information [Line Items]
Entity Registrant Name	Apartment Investment and Management Company
Entity Central Index Key	0000922864
Document Type	10-Q
Document Period End Date	Sep. 30, 2020
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
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 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 1700
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	757-8101
Entity Common Stock, Shares Outstanding		148,865,947
Title of 12(b) Security	Class A Common Stock (Aimco Investment and Management Company)
Security Exchange Name	NYSE
Document Quarterly Report	true
Document Transition Report	false
AIMCO Properties, LP [Member]
Document Information [Line Items]
Entity Registrant Name	AIMCO Properties, L.P.
Entity Central Index Key	0000926660
Document Type	10-Q
Document Period End Date	Sep. 30, 2020
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Entity File Number	0-24497
Entity Tax Identification Number	84-1275621
Entity Address, State or Province	DE
Entity Address, Address Line One	4582 South Ulster Street
Entity Address, Address Line Two	Suite 1700
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	757-8101

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
ASSETS
Buildings and improvements	$ 7,006,395	$ 6,868,543
Land	1,891,763	1,869,048
Total real estate	8,898,158	8,737,591
Accumulated depreciation	(2,858,174)	(2,718,284)
Net real estate	6,039,984	6,019,307
Cash and cash equivalents	228,368	142,902
Restricted cash	40,123	34,800
Mezzanine investment	300,326	280,258
Other assets	383,298	351,472
Assets held for sale	50,030	0
Total assets	7,042,129	6,828,739
LIABILITIES AND EQUITY
Non-recourse property debt and term loan, net	4,058,295	4,230,590
Term loan, net	348,502	0
Revolving credit facility borrowings	0	275,000
Total indebtedness	4,406,797	4,505,590
Accrued liabilities and other	356,538	360,574
Liabilities related to assets held for sale	58,177	0
Total liabilities	4,821,512	4,866,164
Redeemable preferred OP Units	79,449	97,064
Redeemable noncontrolling interests in consolidated real estate partnership	4,371	4,716
Commitments and contingencies (Note 4)
Equity/Partners' Capital:
Common Stock, $0.01 par value, 510,587,500 shares authorized, 148,865,947 and 148,885,197 shares issued/outstanding at September 30, 2020 and December 31, 2019, respectively	1,489	1,489
Additional paid-in capital	4,000,925	3,497,367
Accumulated other comprehensive income	3,579	4,195
Distributions in excess of earnings	(1,884,602)	(1,722,402)
Total Aimco equity	2,121,391	1,780,649
Noncontrolling interests in consolidated real estate partnerships	(60,212)	(3,296)
Common noncontrolling interests in Aimco Operating Partnership	75,618	83,442
Total equity	2,136,797	1,860,795
Total liabilities and equity	7,042,129	6,828,739
AIMCO Properties, LP [Member]
ASSETS
Buildings and improvements	7,006,395	6,868,543
Land	1,891,763	1,869,048
Total real estate	8,898,158	8,737,591
Accumulated depreciation	(2,858,174)	(2,718,284)
Net real estate	6,039,984	6,019,307
Cash and cash equivalents	228,368	142,902
Restricted cash	40,123	34,800
Mezzanine investment	300,326	280,258
Other assets	383,298	351,472
Assets held for sale	50,030	0
Total assets	7,042,129	6,828,739
LIABILITIES AND EQUITY
Non-recourse property debt and term loan, net	4,058,295	4,230,590
Term loan, net	348,502	0
Revolving credit facility borrowings	0	275,000
Total indebtedness	4,406,797	4,505,590
Accrued liabilities and other	356,538	360,574
Liabilities related to assets held for sale	58,177	0
Total liabilities	4,821,512	4,866,164
Redeemable preferred OP Units	79,449	97,064
Redeemable noncontrolling interests in consolidated real estate partnership	4,371	4,716
Commitments and contingencies (Note 4)
Equity/Partners' Capital:
General Partner and Special Limited Partner	2,121,391	1,780,649
Limited Partners	75,618	83,442
Partners’ capital attributable to the Aimco Operating Partnership	2,197,009	1,864,091
Partners' Capital Attributable to Noncontrolling Interest	(60,212)	(3,296)
Total partners’ capital	2,136,797	1,860,795
Total liabilities and equity	$ 7,042,129	$ 6,828,739

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) (Unaudited) - $ / shares	Sep. 30, 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	510,587,500
Common Stock, shares issued (in shares)	148,865,947	148,885,197
Common Stock, shares outstanding (in shares)	148,865,947	148,885,197

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
REVENUES
Rental and other property revenues	$ 215,455	$ 229,827	$ 658,815	$ 684,262
OPERATING EXPENSES
Property operating expenses	74,929	77,484	224,532	232,090
Depreciation and amortization	98,249	97,538	296,414	283,027
General and administrative expenses	8,118	10,595	27,922	31,922
Investment management expenses	2,819	1,581	5,124	4,319
Other expenses, net	17,571	4,002	23,452	12,759
Total operating expenses	201,686	191,200	577,444	564,117
Interest income	3,041	2,824	10,407	8,615
Interest expense	(50,519)	(42,011)	(140,657)	(122,961)
Gain on dispositions of real estate	0	1,146	47,204	356,929
Mezzanine / Unconsolidated partnerships investment income, net	6,870	0	20,553	0
(Loss) income before income tax benefit	(26,562)	874	19,507	363,319
Income tax benefit	1,747	3,096	7,859	1,942
Net (loss) income	(24,815)	3,970	27,366	365,261
Noncontrolling interests:
Net loss (income) attributable to noncontrolling interests in consolidated real estate partnerships	154	58	153	(103)
Net income attributable to preferred noncontrolling interests in Aimco Operating Partnership	(1,687)	(1,933)	(5,415)	(5,800)
Net income attributable to common noncontrolling interests in Aimco Operating Partnership	1,341	(116)	(1,134)	(18,787)
Net income attributable to noncontrolling interests	(192)	(1,991)	(6,396)	(24,690)
Net income attributable to the company	(25,007)	1,979	20,970	340,571
Net income attributable to the company's preferred equity holders	0	0	0	(7,335)
Net (income) loss attributable to participating securities	(39)	24	(125)	(431)
Net income attributable to the company's common equity holders	$ (25,046)	$ 2,003	$ 20,845	$ 332,805
Net income attributable to Aimco per common share – basic and diluted	$ (0.17)	$ 0.01	$ 0.14	$ 2.26
Weighted average common shares/units outstanding - basic	148,544	148,434	148,532	147,474
Weighted average common shares/units outstanding - diluted	148,544	148,636	148,628	147,692
AIMCO Properties, LP [Member]
REVENUES
Rental and other property revenues	$ 215,455	$ 229,827	$ 658,815	$ 684,262
OPERATING EXPENSES
Property operating expenses	74,929	77,484	224,532	232,090
Depreciation and amortization	98,249	97,538	296,414	283,027
General and administrative expenses	8,118	10,595	27,922	31,922
Investment management expenses	2,819	1,581	5,124	4,319
Other expenses, net	17,571	4,002	23,452	12,759
Total operating expenses	201,686	191,200	577,444	564,117
Interest income	3,041	2,824	10,407	8,615
Interest expense	(50,519)	(42,011)	(140,657)	(122,961)
Gain on dispositions of real estate	0	1,146	47,204	356,929
Mezzanine / Unconsolidated partnerships investment income, net	6,870	0	20,553	0
(Loss) income before income tax benefit	(26,562)	874	19,507	363,319
Income tax benefit	1,747	3,096	7,859	1,942
Net (loss) income	(24,815)	3,970	27,366	365,261
Noncontrolling interests:
Net loss (income) attributable to noncontrolling interests in consolidated real estate partnerships	154	58	153	(103)
Net income attributable to preferred noncontrolling interests in Aimco Operating Partnership	(1,687)	(1,933)	(5,415)	(13,135)
Net income attributable to the company	(24,661)	4,028	27,519	365,158
Net (income) loss attributable to participating securities	(39)	43	(125)	(429)
Net income attributable to the company's common equity holders	$ (26,387)	$ 2,138	$ 21,979	$ 351,594
Net income attributable to Aimco per common share – basic and diluted	$ (0.17)	$ 0.01	$ 0.14	$ 2.26
Weighted average common shares/units outstanding - basic	156,508	156,618	156,559	155,644
Weighted average common shares/units outstanding - diluted	156,508	156,879	156,692	155,971
Unconsolidated Real Estate Partnerships [Member]
OPERATING EXPENSES
Mezzanine / Unconsolidated partnerships investment income, net	$ 277	$ 288	$ 629	$ 591
Unconsolidated Real Estate Partnerships [Member] | AIMCO Properties, LP [Member]
OPERATING EXPENSES
Mezzanine / Unconsolidated partnerships investment income, net	$ 277	$ 288	$ 629	$ 591

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net (loss) income	$ (24,815)	$ 3,970	$ 27,366	$ 365,261
Unrealized losses on available for sale debt securities	(243)	(402)	(658)	(325)
Comprehensive (loss) income	(25,058)	3,568	26,708	364,936
Comprehensive income attributable to noncontrolling interests	(177)	(1,967)	(6,354)	(24,671)
Comprehensive (loss) income attributable to Aimco	(25,235)	1,601	20,354	340,265
AIMCO Properties, LP [Member]
Net (loss) income	(24,815)	3,970	27,366	365,261
Unrealized losses on available for sale debt securities	(243)	(402)	(658)	(325)
Comprehensive (loss) income	(25,058)	3,568	26,708	364,936
Comprehensive income attributable to noncontrolling interests	154	58	153	(103)
Comprehensive (loss) income attributable to Aimco	$ (24,904)	$ 3,626	$ 26,861	$ 364,833

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Distributions in Excess of Earnings	Distributions in Excess of EarningsCumulative Effect, Period of Adoption, Adjustment	Total Aimco Equity	Total Aimco EquityCumulative Effect, Period of Adoption, Adjustment	Noncontrolling Interests In Consolidated Real Estate Partnerships	Common Noncontrolling Interests In Aimco Operating Partnership
Balances at Dec. 31, 2018	$ 1,763,641		$ 125,000	$ 1,446	$ 3,515,686	$ 4,794	$ (1,947,507)		$ 1,699,419		$ (2,967)	$ 67,189
Balances (in shares) at Dec. 31, 2018			5,000	144,623
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchases of Common Stock	(20,682)			$ (5)	(20,677)				(20,682)
Repurchases of Common Stock (in shares)				(461)
Redemption of Preferred Stock	(125,000)		$ (125,000)		4,089		(4,089)		(125,000)
Redemption of Preferred Stock (in shares)			(5,000)
Issuance of Aimco Operating Partnership units	3,034											3,034
Redemption of Aimco Operating Partnership units	(4,958)				6,242				6,244		0	(11,202)
Redemption of Aimco Operating Partnership units (in shares)				127
Redemption of Aimco Operating Partnership units				$ 2
Amortization of share-based compensation cost	7,182				4,795				4,795			2,387
Amortization of share-based compensation cost (in shares)				22
Effect of changes in ownership for consolidated entities	0				(12,123)				(12,123)		3,357	8,766
Contribution from noncontrolling interest in consolidated real estate partnerships	4,911										4,911
Purchase of noncontrolling interest in consolidated real estate partnerships	(3,780)										(3,780)
Change in accumulated other comprehensive income	(325)					(306)			(306)			(19)
Net income (loss)	359,461						340,571		340,571		103	18,787
Common Stock dividends	(183,579)						(183,579)		(183,579)
Common Stock issued to Common Stockholders in special dividend	(516)			$ 45	(561)				(516)
Common Stock issued to Common Stockholders in special dividend (in shares)				4,492
Preferred Stock dividends	(3,247)						(3,247)		(3,247)
Distributions to noncontrolling interests	(9,970)										(143)	(9,827)
Other, net	(98)			$ 1	(118)		0		(117)		19
Other, net (in shares)				82
Balances at Sep. 30, 2019	1,786,074		$ 0	$ 1,489	3,497,333	4,488	(1,797,851)		1,705,459		1,500	79,115
Balances (in shares) at Sep. 30, 2019			0	148,885
Balances at Jun. 30, 2019	1,842,866			$ 1,488	3,498,629	4,866	(1,741,765)		1,763,218		(2,718)	82,366
Balances (in shares) at Jun. 30, 2019				148,827
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of Aimco Operating Partnership units	(826)				2,820				2,821		0	(3,647)
Redemption of Aimco Operating Partnership units (in shares)				57
Redemption of Aimco Operating Partnership units				$ 1
Amortization of share-based compensation cost	1,958				1,163				1,163			795
Effect of changes in ownership for consolidated entities	0				(5,104)				(5,104)		2,315	2,789
Contribution from noncontrolling interest in consolidated real estate partnerships	4,911										4,911
Purchase of noncontrolling interest in consolidated real estate partnerships	(2,863)										(2,863)
Change in accumulated other comprehensive income	(402)					(378)			(378)			(24)
Net income (loss)	2,037						1,979		1,979		(58)	116
Common Stock dividends	(58,065)						(58,065)		(58,065)
Distributions to noncontrolling interests	(3,367)										(87)	(3,280)
Other, net	(175)				(175)		0		(175)
Other, net (in shares)				1
Balances at Sep. 30, 2019	1,786,074		$ 0	$ 1,489	3,497,333	4,488	(1,797,851)		1,705,459		1,500	79,115
Balances (in shares) at Sep. 30, 2019			0	148,885
Balances at Dec. 31, 2019	1,860,795	$ (277)	$ 0	$ 1,489	3,497,367	4,195	(1,722,402)	$ (277)	1,780,649	$ (277)	(3,296)	83,442
Balances (in shares) at Dec. 31, 2019			0	148,885
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchases of Common Stock	(10,004)		$ 0	$ (2)	(10,002)				(10,004)
Repurchases of Common Stock (in shares)				(234)
Redemption of Aimco Operating Partnership units	(1,739)				5,135				5,137			(6,876)
Redemption of Aimco Operating Partnership units (in shares)				159
Redemption of Aimco Operating Partnership units				$ 2
Amortization of share-based compensation cost	7,065				3,911				3,911			3,154
Amortization of share-based compensation cost (in shares)				25
Effect of changes in ownership for consolidated entities	447,688				504,361				504,361		(61,320)	4,647
Contribution from noncontrolling interest in consolidated real estate partnerships	4,701										4,701
Change in accumulated other comprehensive income	(658)					(616)			(616)			(42)
Net income (loss)	22,298						20,970		20,970		194	1,134
Common Stock dividends	(182,893)						(182,893)		(182,893)
Distributions to noncontrolling interests	(10,019)										(178)	(9,841)
Other, net	(160)				153		0		153		(313)
Other, net (in shares)				31
Balances at Sep. 30, 2020	2,136,797		$ 0	$ 1,489	4,000,925	3,579	(1,884,602)		2,121,391		(60,212)	75,618
Balances (in shares) at Sep. 30, 2020			0	148,866
Balances at Jun. 30, 2020	1,774,236			$ 1,489	3,491,277	3,807	(1,798,561)		1,698,012		(3,190)	79,414
Balances (in shares) at Jun. 30, 2020				148,865
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of Aimco Operating Partnership units	(484)								0		0	(484)
Amortization of share-based compensation cost	1,954				902				902			1,052
Effect of changes in ownership for consolidated entities	447,688				508,709				508,709		(61,356)	335
Contribution from noncontrolling interest in consolidated real estate partnerships	4,701										4,701
Change in accumulated other comprehensive income	(243)					(228)			(228)			(15)
Net income (loss)	(26,379)						(25,007)		(25,007)		(31)	(1,341)
Common Stock dividends	(61,034)						(61,034)		(61,034)
Distributions to noncontrolling interests	(3,413)										(70)	(3,343)
Other, net	(229)				37		0		37		(266)
Other, net (in shares)				1
Balances at Sep. 30, 2020	$ 2,136,797		$ 0	$ 1,489	$ 4,000,925	$ 3,579	$ (1,884,602)		$ 2,121,391		$ (60,212)	$ 75,618
Balances (in shares) at Sep. 30, 2020			0	148,866

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 27,366	$ 365,261
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	296,414	283,027
Gain on dispositions of real estate	(47,204)	(356,929)
Income tax benefit	(7,859)	(1,942)
Other adjustments	11,617	10,429
Net changes in operating assets and operating liabilities	(14,458)	(21,098)
Net cash provided by operating activities	265,876	278,748
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate and deposits related to purchases of real estate	(98,573)	(131,613)
Capital expenditures	(272,269)	(292,749)
Proceeds from dispositions of real estate	36,869	422,463
Purchases of corporate assets	(13,539)	(14,825)
Other investing activities	(8,457)	719
Net cash used in investing activities	(355,969)	(16,005)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from non-recourse property debt	608,756	667,965
Principal repayments on non-recourse property debt	(702,354)	(390,346)
Proceeds from term loan	350,000	0
Net repayments of revolving credit facility	(275,000)	(160,360)
Payment of debt issuance costs	(7,663)	(3,625)
Payment of debt extinguishment costs	(13,175)	(840)
Repurchases of common stock or common units	(10,004)	(20,682)
Repurchases of preferred stock or preferred units	0	(125,000)
Payment of dividends to holders of Common Stock	(183,003)	(183,319)
Payment of dividends to holders of Preferred Stock	0	(3,247)
Payment of distributions to noncontrolling interests	(15,863)	(16,320)
Redemptions of noncontrolling interests in the Aimco Operating Partnership	(19,355)	(5,071)
Contribution from noncontrolling interests in consolidated real estate partnerships	463,523	4,911
Purchases of noncontrolling interests in consolidated real estate partnerships	0	(3,780)
Other financing activities	(14,980)	(2,399)
Net cash provided by (used in) financing activities	180,882	(242,113)
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	90,789	20,630
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD	177,702	72,595
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT END OF PERIOD	268,491	93,225
AIMCO Properties, LP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	27,366	365,261
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	296,414	283,027
Gain on dispositions of real estate	(47,204)	(356,929)
Income tax benefit	(7,859)	(1,942)
Other adjustments	11,617	10,429
Net changes in operating assets and operating liabilities	(14,458)	(21,098)
Net cash provided by operating activities	265,876	278,748
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate and deposits related to purchases of real estate	(98,573)	(131,613)
Capital expenditures	(272,269)	(292,749)
Proceeds from dispositions of real estate	36,869	422,463
Purchases of corporate assets	(13,539)	(14,825)
Other investing activities	(8,457)	719
Net cash used in investing activities	(355,969)	(16,005)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from non-recourse property debt	608,756	667,965
Principal repayments on non-recourse property debt	(702,354)	(390,346)
Proceeds from term loan	350,000	0
Net repayments of revolving credit facility	(275,000)	(160,360)
Payment of debt issuance costs	(7,663)	(3,625)
Payment of debt extinguishment costs	(13,175)	(840)
Repurchases of common stock or common units	(10,004)	(20,682)
Repurchases of preferred stock or preferred units	0	(125,000)
Payment of distributions to General Partner and Special Limited Partner	(183,003)	(183,319)
Payment of distributions to Limited Partners	(10,136)	(10,211)
Payment of dividends to holders of Preferred Stock	(5,415)	(9,047)
Payment of distributions to noncontrolling interests	(312)	(309)
Redemption of common and preferred units	(19,355)	(5,071)
Contribution from noncontrolling interests in consolidated real estate partnerships	463,523	4,911
Purchases of noncontrolling interests in consolidated real estate partnerships	0	(3,780)
Other financing activities	(14,980)	(2,399)
Net cash provided by (used in) financing activities	180,882	(242,113)
NET INCREASE IN CASH, CASH EQUIVALENTS, AND RESTRICTED CASH	90,789	20,630
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT BEGINNING OF PERIOD	177,702	72,595
CASH, CASH EQUIVALENTS, AND RESTRICTED CASH AT END OF PERIOD	$ 268,491	$ 93,225

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Partners' Capital - USD ($) $ in Thousands	Total	AIMCO Properties, LP [Member]	AIMCO Properties, LP [Member]Cumulative Effect, Period of Adoption, Adjustment [Member]	AIMCO Properties, LP [Member]Preferred Units [Member]	AIMCO Properties, LP [Member]General Partner and Special Limited Partner [Member]	AIMCO Properties, LP [Member]General Partner and Special Limited Partner [Member]Cumulative Effect, Period of Adoption, Adjustment [Member]	AIMCO Properties, LP [Member]Limited Partners [Member]	AIMCO Properties, LP [Member]Partners Capital Attributable To The Partnership [Member]	AIMCO Properties, LP [Member]Partners Capital Attributable To The Partnership [Member]Cumulative Effect, Period of Adoption, Adjustment [Member]	AIMCO Properties, LP [Member]Noncontrolling Interests In Consolidated Real Estate Partnerships
Balances at Dec. 31, 2018		$ 1,763,641		$ 125,000	$ 1,574,419		$ 67,189	$ 1,766,608		$ (2,967)
Increase (Decrease) in Partners' Capital [Roll Forward]
Repurchases of common partnership units		(20,682)			(20,682)			(20,682)
Redemption of preferred units		(125,000)		$ (125,000)				(125,000)
Issuance of Aimco Operating Partnership units	$ 3,034	3,034					3,034	3,034
Redemption of Aimco Operating Partnership units	4,958	(4,958)			6,244		(11,202)	(4,958)
Amortization of share-based compensation cost		7,182			4,795		2,387	7,182
Effect of changes in ownership of consolidated entities					(12,123)		8,766	(3,357)		3,357
Contribution from noncontrolling interest in consolidated real estate partnerships	4,911	4,911								4,911
Purchase of noncontrolling interest in consolidated real estate partnerships		(3,780)								(3,780)
Change in accumulated other comprehensive income	(325)	(325)			(306)		(19)	(325)
Net income (loss)	359,461	359,461			340,571		18,787	359,358		103
Distributions paid to common unitholders		(193,406)			(183,579)		(9,827)	(193,406)
Common partnership units issued to common unitholders in special distribution		(516)			(516)			(516)
Distributions paid to preferred unitholders		(3,247)			(3,247)			(3,247)
Distributions to noncontrolling interests	(9,970)
Distributions paid to noncontrolling interests in consolidated real estate partnerships		(143)								(143)
Other, net		(98)			(117)			(117)		19
Balances at Sep. 30, 2019		1,786,074			1,705,459		79,115	1,784,574		1,500
Balances at Jun. 30, 2019		1,842,866			1,763,218		82,366	1,845,584		(2,718)
Increase (Decrease) in Partners' Capital [Roll Forward]
Redemption of Aimco Operating Partnership units	826	(826)			2,821		(3,647)	(826)
Amortization of share-based compensation cost		1,958			1,163		795	1,958
Effect of changes in ownership of consolidated entities					(5,104)		2,789	(2,315)		2,315
Contribution from noncontrolling interest in consolidated real estate partnerships	4,911	4,911								4,911
Purchase of noncontrolling interest in consolidated real estate partnerships		(2,863)								(2,863)
Change in accumulated other comprehensive income	(402)	(402)			(378)		(24)	(402)
Net income (loss)	2,037	2,037			1,979		116	2,095		(58)
Distributions paid to common unitholders		(61,345)			(58,065)		(3,280)	(61,345)
Distributions to noncontrolling interests	(3,367)
Distributions paid to noncontrolling interests in consolidated real estate partnerships		(87)								(87)
Other, net		(175)			(175)			(175)
Balances at Sep. 30, 2019		1,786,074			1,705,459		79,115	1,784,574		1,500
Balances at Dec. 31, 2019		1,860,795	$ (277)		1,780,649	$ (277)	83,442	1,864,091	$ (277)	(3,296)
Increase (Decrease) in Partners' Capital [Roll Forward]
Repurchases of common partnership units		(10,004)			(10,004)			(10,004)
Redemption of Aimco Operating Partnership units	1,739	(1,739)			5,137		(6,876)	(1,739)
Amortization of share-based compensation cost		7,065			3,911		3,154	7,065
Effect of changes in ownership of consolidated entities		447,688			504,361		4,647	509,008		(61,320)
Contribution from noncontrolling interest in consolidated real estate partnerships	4,701	4,701								4,701
Change in accumulated other comprehensive income	(658)	(658)			(616)		(42)	(658)
Net income (loss)	22,298	22,298			20,970		1,134	22,104		194
Distributions paid to common unitholders		(192,734)			(182,893)		(9,841)	(192,734)
Distributions to noncontrolling interests	(10,019)	(178)								(178)
Other, net		(160)			153			153		(313)
Balances at Sep. 30, 2020		2,136,797			2,121,391		75,618	2,197,009		(60,212)
Balances at Jun. 30, 2020		1,774,236			1,698,012		79,414	1,777,426		(3,190)
Increase (Decrease) in Partners' Capital [Roll Forward]
Redemption of Aimco Operating Partnership units	484	(484)					(484)	(484)
Amortization of share-based compensation cost		1,954			902		1,052	1,954
Effect of changes in ownership of consolidated entities		447,688			508,709		335	509,044		(61,356)
Contribution from noncontrolling interest in consolidated real estate partnerships	4,701	4,701								4,701
Change in accumulated other comprehensive income	(243)	(243)			(228)		(15)	(243)
Net income (loss)	(26,379)	(26,379)			(25,007)		(1,341)	(26,348)		(31)
Distributions paid to common unitholders		(64,377)			(61,034)		(3,343)	(64,377)
Distributions to noncontrolling interests	$ (3,413)	(70)								(70)
Other, net		(229)			37			37		(266)
Balances at Sep. 30, 2020		$ 2,136,797			$ 2,121,391		$ 75,618	$ 2,197,009		$ (60,212)

Organization

Organization	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization	Note 1 — Organization Apartment Investment and Management Company, or Aimco, is a Maryland corporation incorporated on January 10, 1994. Aimco is a self-administered and self-managed real estate investment trust, or REIT. AIMCO Properties, L.P., or the Aimco Operating Partnership, is a Delaware limited partnership formed on May 16, 1994, to conduct our business, which is focused on the ownership, management, redevelopment, and some development of quality apartment communities located in several of the largest markets in the United States. Aimco, through its wholly-owned subsidiaries, AIMCO-GP, Inc. and AIMCO-LP Trust, holds a majority of the ownership interests in the Aimco Operating Partnership. Aimco conducts all of its business and owns all of its assets through the Aimco Operating Partnership. Interests in the Aimco Operating Partnership that are held by limited partners other than Aimco are referred to as OP Units. OP Units include common partnership units, which we refer to as common OP Units, as well as preferred partnership units, which we refer to as preferred OP Units. As of September 30, 2020, after elimination of units held by consolidated subsidiaries, the Aimco Operating Partnership had 159,182,513 common OP Units outstanding. As of September 30, 2020, Aimco owned 148,865,947 of the common OP Units of the Aimco Operating Partnership and Aimco had an equal number of shares of its Class A Common Stock outstanding, which we refer to as Common Stock. Aimco’s ownership of the total common OP units outstanding represents a 93.5% legal interest in the Aimco Operating Partnership and a 94.9% economic interest. Except as the context otherwise requires, “we,” “our,” and “us” refer to Aimco, the Aimco Operating Partnership, and their consolidated subsidiaries, collectively. We own and operate a portfolio of apartment communities, diversified by both geography and price point, in 17 states and the District of Columbia. As of September 30, 2020, our portfolio included 126 apartment communities with 33,209 apartment homes in which we held an average ownership of approximately 95%. We consolidated 122 of these apartment communities with 33,067 apartment homes. On September 14, 2020, we announced a Board-led plan, informed by active and regular engagement with shareholders, to reduce financial risk and execution risk, and to increase shareholder value by division of our business between two public entities. The first, with approximately 90% of our estimated fair value, will be known as Apartment Income REIT, or AIR. The second entity, with 10% of our estimated fair value, will be known as Aimco, or sometimes for clarity, as “new” Aimco, and is expected to hold the non-traditional assets, specified below. Separation costs for the three and nine months ended September 30, 2020, totaled $11.9 million and $12.6 million, respectively, are reflected in other expenses, net on our condensed consolidated statement of operations. Following the completion of the separation, we expect to retain the redevelopment and development business, 25 consolidated communities including 16 multi-family communities securing a $534 million note payable due to AIR, and four non-100% owned communities that we do not consolidate. In addition, we expect to hold non-traditional assets such as other investments including 1001 Brickell Bay Tower and our loan to, and equity option in, the partnership that owns Parkmerced Apartments.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 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 Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted in accordance with such rules and regulations, although management believes the disclosures are adequate to prevent the information presented from being misleading. In the opinion of management, all adjustments, consisting of normal recurring items, considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2020, are not necessarily indicative of the results that may be expected for the year ending December 31, 2020. The condensed consolidated balance sheets of Aimco and the Aimco Operating Partnership as of December 31, 2019 , have been derived from their respective audited financial statements at that date, but do not include all of the information and disclosures required by GAAP for complete financial statements. For further information, refer to the financial statements and notes thereto included in Aimco’s and the Aimco Operating Partnership’s combined Annual Report on Form 10-K for the year ended December 31, 2019 . Except where indicated, the footnotes refer to both Aimco and the Aimco Operating Partnership. Principles of Consolidation Aimco’s accompanying condensed consolidated financial statements include the accounts of Aimco, the Aimco Operating Partnership, and their consolidated subsidiaries. The Aimco Operating Partnership’s condensed consolidated financial statements include the accounts of the Aimco Operating Partnership and its consolidated subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. We consolidate a variable interest entity, or 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. Interests in the Aimco Operating Partnership that are held by limited partners other than Aimco are reflected in Aimco’s accompanying condensed consolidated balance sheets as noncontrolling interests in the Aimco Operating Partnership. Interests in partnerships consolidated by the Aimco Operating Partnership that are held by third parties are reflected in our accompanying condensed consolidated balance sheets as noncontrolling interests in consolidated real estate partnerships. Redeemable Preferred OP Units As described in Note 5, the preferred OP Units may be redeemed at the holder’s option and are therefore presented within temporary equity in Aimco’s condensed consolidated balance sheets and within temporary capital in the Aimco Operating Partnership’s condensed consolidated balance sheets. The following table presents a reconciliation of the Aimco Operating Partnership’s preferred OP Units from December 31, 2019, to September 30, 2020 (in thousands): Balance at December 31, 2019 $ 97,064 Preferred distributions (5,415 ) Redemption of preferred units (17,615 ) Net income 5,415 Balance at September 30, 2020 $ 79,449 The Aimco Operating Partnership has outstanding various classes of redeemable preferred OP Units. As of September 30, 2020 and December 31, 2019, the Aimco Operating Partnership had 2,938,802 and 3,643,399 redeemable preferred OP Units, respectively, issued and outstanding. Distributions per annum range from 1.92% to 8.75% per class and $0.48 to $8.00 per unit. Revenue from Leases The majority of lease payments we receive from our residents and tenants are fixed. We receive variable payments from our residents and commercial tenants primarily for utility reimbursements. For the three and nine months ended September 30, 2020 and 2019, our total lease income was comprised of the following amounts for all operating leases (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Fixed lease income $ 200,295 $ 213,945 $ 619,447 $ 639,359 Variable lease income 14,578 15,005 40,842 42,814 Straight-line rent write-off (1) — — (2,927 ) — Total lease income $ 214,873 $ 228,950 $ 657,362 $ 682,173 (1) We monitor the collectability of all unpaid rent amounts. The onset of COVID-19 and the anticipated economic slowdown resulted in a $2.9 million write-off of accrued straight-line rent during the nine months ended September 30, 2020. Additionally, we wrote-off the related deferred leasing costs of $2.4 million during the nine months ended September 30, 2020. The write-offs of deferred leasing costs are recorded in depreciation and amortization in our condensed consolidated statements of operations. In response to the economic effects of the COVID-19 pandemic and government al lockdown , many jurisdictions where our communities are located have enacted protections for residents and commercial tenants, including government - mandated rent deferrals, rent freezes, repayment extensions, fee abatement measures or concessions, and prohibitions on lease terminations or evictions for tenants . Some states and municipalities are also implementing rental assistance programs and encouraging landlord - tenant negotiations . On April 10, 2020, the Financial Accounting Standards Board, or FASB, issued a Staff Q&A to respond to some frequently asked questions about accounting for lease concessions, including deferrals or reductions of future lease payments. Consequently, in accordance with the Staff Q&A issued by the FASB, we may elect to record rent relief when granted rather than over the remaining term of the lease. Our residential tenants represent approximately 97% of revenue and our commercial tenants represent approximately 3% of revenue for the three months ended September 30, 2020. For the three and nine months ended September 30, 2020, we granted to commercial tenants $0.6 million and $1.0 million in rent relief, respectively, and elected to record these as a reduction of variable lease income in the table above. Use of Estimates The preparation of our condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts included in the financial statements and accompanying notes thereto. Actual results could differ from those estimates. Reclassifications and Revisions For the 2020 presentation of our condensed consolidated statements of operations, we have added a caption for investment management expenses. We have reclassified certain items from property operating expenses, general and administrative expenses, and other expenses, net, in our 2019 presentation to conform to the current presentation. Accounting Pronouncements Adopted in the Current Year On January 1, 2020, we adopted ASC 326, Financial Instruments – Credit Losses We adopted the credit loss standard using the modified-retrospective approach. We recorded a cumulative-effect adjustment for the estimated credit loss associated with our notes receivable of $0.3 million in distributions in excess of earnings and partners’ capital in our condensed consolidated balance sheets as of January 1, 2020. As of the date of adoption, the fair value of our AFS debt securities exceeded their carrying value and no estimate of credit loss was required for these instruments.

Significant Transactions

Significant Transactions	9 Months Ended
	Sep. 30, 2020
Significant Transactions [Abstract]
Significant Transactions	Note 3 — Significant Transactions Joint Venture Transaction On September 8, 2020, we formed a joint venture with a passive institutional investor, to own a portfolio of 12 multi-family apartment communities with 4,051 homes located in California. The communities included in the joint venture were valued at $2.4 billion, or approximately $592,000 per apartment home. The joint venture has existing property debt of $1.22 billion and an implied equity value of $1.18 billion. In exchange for a 39% interest subject to $475 million of property debt, we received $461 million. We retain ownership of 61% of the joint venture and will control and operate the communities in exchange for property and asset management fees. We evaluated the joint venture and concluded that we will continue to consolidate these communities. The difference between the consideration received and the carrying value of the interest sold was recognized in additional paid-in capital. 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 this acquisition is set forth in the table below (dollars in thousands): Number of apartment homes 271 Purchase price $ 89,600 Capitalized transaction costs 2,506 Total consideration $ 92,106 Consideration allocated to land $ 56,251 Consideration allocated to building and improvements 34,645 Consideration allocated to intangible assets (1) 1,506 Consideration allocated to below-market lease liabilities (2) (296 ) Total consideration $ 92,106 (1) Intangible assets include in-place leases and leasing costs with a weighted-average term of 0.5 (2) Below-market leases have a weighted-average term of 0.8 Dispositions of Apartment Communities During the three months ended September 30, 2020 and 2019, no apartment communities were sold. During the nine months ended September 30, 2020 and 2019, we sold one apartment community with 219 apartment homes for a gain on disposition of $47.2 million and sold eight apartment communities with 2,605 apartment homes for a gain on dispositions of $356.9 million, respectively. The apartment communities sold were in lower-rated locations within our primary markets and had average revenues per apartment home significantly below those of our retained portfolio. From time to time we may be marketing for sale certain apartment communities that are inconsistent with our long-term investment strategy. At the end of each reporting period we evaluate whether such communities meet the criteria to be classified as held for sale. As of September 30, 2020, we classified a 266-apartment home community as held for sale that is expected to be sold for gross proceeds of approximately $126 million later in 2020. Term Loan On April 20, 2020, we secured a $350.0 million term loan. The loan matures on April 20, 2021, includes a one-year Life Science Developer Investment During the three months ended September 30, 2020, we made a $50 million commitment to IQHQ, a privately-held life-sciences real estate development company. In addition, we gained the right to collaborate with IQHQ on any multifamily component at its future development sites.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 4 — Commitments and Contingencies Commitments In connection with our redevelopment, development, and other capital additions activities, we have entered into various construction-related contracts and we have made commitments to complete redevelopment and development of certain apartment communities, pursuant to financing or other arrangements. As of September 30, 2020, our commitments related to these capital activities totaled approximately $184 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. Legal Matters In addition to the matters described below, we are a party to various legal actions and administrative proceedings arising in the ordinary course of business, some of which are covered by our general liability insurance program, and none of which we expect to have a material adverse effect on our consolidated financial condition, results of operations, or cash flows. Environmental Various federal, state, and local laws subject apartment community owners or operators to liability for management, and the costs of removal or remediation, of certain potentially hazardous materials that may be present in the land or buildings of an apartment community. Such laws often impose liability without regard to fault or whether the owner or operator knew of, or was responsible for, the presence of such materials. The presence of, or the failure to manage or remediate properly, these materials may adversely affect occupancy at such apartment communities as well as the ability to sell or finance such apartment communities. In addition, governmental agencies may bring claims for costs associated with investigation and remediation actions. Moreover, private plaintiffs may potentially make claims for investigation and remediation costs they incur or for personal injury, disease, disability, or other infirmities related to the alleged presence of hazardous materials. In addition to potential environmental liabilities or costs associated with our current apartment communities, we may also be responsible for such liabilities or costs associated with communities we acquire or manage in the future, or apartment communities we no longer own or operate. We are engaged in discussions with the Environmental Protection Agency, or EPA, regarding contaminated groundwater near an Indiana apartment community that has not been owned by us since 2008. The contamination allegedly derives from a dry cleaner that operated on our former property, prior to our ownership. We undertook a voluntary remediation of the dry cleaner contamination under state oversight. In 2016, EPA listed our former community and a number of residential communities in the vicinity on the National Priorities List, or NPL (i.e., as a Superfund site). In May 2018, we prevailed on our federal judicial appeal vacating the Superfund listing. We continue to work with EPA to formulate an agreed order to reimburse EPA costs and finish clean up of the site outside the Superfund program. Although the outcome of this process is uncertain, we do not expect the resolution to have a material adverse effect on our consolidated financial condition, results of operations, or cash flows. We also have a contingent environmental liability related to a property in Lake Tahoe, California. An entity owned by us was the former general partner of a now-dissolved partnership that previously owned a site where a laundromat, with a self-service dry-cleaning machine, operated. That entity and the current property owner have been remediating the site since 2009, under the oversight of the Lahontan Regional Water Quality Control Board, or Lahontan. In May 2017, Lahontan issued a final cleanup and abatement order that names four potentially-responsible parties, acknowledges that there may be additional responsible parties, and requires the named parties to perform additional groundwater investigation and corrective actions with respect to onsite and offsite contamination. We appealed the final order, and on June 1, 2020, the court vacated the Order against us. However, there are still civil suits pending related to this contingent liability. Although the outcome of this process is uncertain, we do not expect the resolution to have a material adverse effect on our consolidated financial condition, results of operations, or cash flows. We have determined that our legal obligations to remove or remediate certain potentially hazardous materials may be conditional asset retirement obligations, as defined by GAAP. Except in limited circumstances where the asset retirement activities are expected to be performed in connection with a planned construction project or apartment community casualty, we believe that the fair value of our asset retirement obligations cannot be reasonably estimated due to significant uncertainties in the timing and manner of settlement of those obligations. Asset retirement obligations that are reasonably estimable as of September 30, 2020, are immaterial to our consolidated financial condition, results of operations, and cash flows.

Earnings and Dividends per Shar

Earnings and Dividends per Share and Unit	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings and Dividends per Share and Unit	Note 5 — Earnings and Dividends per Share and 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. 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 total shareholder return, or 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 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 restricted stock awards that are subject to time-based vesting receive non-forfeitable dividends similar to shares of Common Stock and common partnership units prior to vesting, and our TSR long-term incentive partnership 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 three and nine months ended September 30, 2020 and 2019, are as follows (in thousands, except per share and per unit data): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Earnings per share Numerator: Basic and dilutive net (loss) income attributable to Aimco common stockholders $ (25,046 ) $ 2,003 $ 20,845 $ 332,805 Denominator – shares: Basic weighted-average Common Stock outstanding 148,544 148,434 148,532 147,474 Dilutive share equivalents outstanding — 202 96 218 Dilutive weighted-average Common Stock outstanding 148,544 148,636 148,628 147,692 Earnings per share – basic and diluted $ (0.17 ) $ 0.01 $ 0.14 $ 2.26 Non-dilutive share equivalents outstanding 9,007 — 8,337 — Earnings per unit Numerator: Basic and dilutive net (loss) income attributable to the Aimco Operating Partnership's common unitholders $ (26,387 ) $ 2,138 $ 21,979 $ 351,594 Denominator – units Basic weighted-average common partnership units outstanding 156,508 156,618 156,559 155,644 Dilutive partnership unit equivalents outstanding — 261 133 327 Dilutive weighted-average common partnership units outstanding 156,508 156,879 156,692 155,971 Earnings per unit – basic and diluted $ (0.17 ) $ 0.01 $ 0.14 $ 2.26 Non-dilutive partnership unit equivalents outstanding 2,220 — 1,596 — The Aimco Operating Partnership has various classes of preferred OP Units, which may be redeemed at the holders’ option. The Aimco Operating Partnership may redeem these units for cash, or at its option, shares of Common Stock. As of September 30, 2020, these preferred OP Units were potentially redeemable for approximately 2.4 million shares of Common Stock (based on the period end market price), or cash. The Aimco Operating Partnership has a redemption policy that requires cash settlement of redemption requests for the preferred OP Units, subject to limited exceptions. Accordingly, we have excluded these securities from earnings per share and unit computations for the periods presented above, and we expect to exclude them in future periods. Dividends and distributions paid during the three and nine months ended September 30, 2020 and 2019, were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Dividends and distributions paid $ 0.41 $ 0.39 $ 1.23 $ 2.80 In the first quarter of 2019, the Board of Directors authorized a special dividend and special distribution of $2.02, which is included in the $2.80 in the table above. The special dividend and distribution in the first quarter of 2019 consisted of the below (in millions): Aimco Special Dividend: Cash $ 67.1 Shares of Common Stock 4.5 Cash paid in lieu of issuing fractional shares $ 0.4 Aimco Operating Partnership Special Distribution: Cash $ 72.7 Common partnership units 4.8 Cash paid in lieu of issuing fractional units $ 0.4 In connection with the 2019 special dividend and distribution, the Board of Directors authorized a reverse stock split during the three months ended March 31, 2019. The reverse split combined every 1.03119 common shares and common partnership units into one common share or common partnership unit and was intended to neutralize the dilutive impact of the shares and units issued in the special dividend and distribution. As a result, the number of shares and units outstanding after the dividend/distribution and reverse split was unchanged from the number outstanding immediately prior to the two actions.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 6 — Fair Value Measurements Recurring Fair Value Measurements We measure at fair value on a recurring basis our investments in the securitization trust that holds certain of our property debt, which we classify as AFS debt securities. These investments are presented within other assets in the condensed consolidated balance sheets. We hold several positions in the securitization trust that pay interest currently and we also hold the first loss position in the securitization trust, which accrues interest over the term of the investment. These investments were acquired at a discount to face value and we are accreting the discount to the $100.9 million face value of the investments through interest income using the effective interest method over the remaining expected term of the investments, which as of September 30, 2020, was approximately 0.8 years. Our amortized cost basis for these investments, which represents the original cost adjusted for interest accretion less interest payments received, was $95.3 million and $90.0 million as of September 30, 2020, and December 31, 2019, respectively. Our investments in AFS debt securities are classified within Level 2 of the GAAP fair value hierarchy. We estimate the fair value of these investments using an income and market approach with primarily observable inputs, including yields and other information regarding similar types of investments, and adjusted for certain unobservable inputs specific to these investments. The fair value of the positions that pay interest currently typically moves in an inverse relationship with movements in interest rates. The fair value of the first loss position is primarily correlated to collateral quality and demand for similar subordinate commercial mortgage-backed securities. During the nine months ended September 30, 2020, we paid an upfront premium of $12.1 million for the option to enter into an 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 limited 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 in our condensed 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 condensed 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 in our condensed consolidated statements of cash flows. The following table summarizes fair value for our AFS debt securities and our interest rate option (in thousands): As of September 30, 2020 As of December 31, 2019 Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 AFS debt securities $ 98,874 $ — $ 98,874 $ — $ 94,251 $ — $ 94,251 $ — Interest rate option 10,026 — 10,026 — — — — — Fair Value Disclosures We believe that the carrying value of the consolidated amounts of cash and cash equivalents, restricted cash, accounts receivable, and accounts payable approximated their fair value as of September 30, 2020, and December 31, 2019, due to their relatively short-term nature and high probability of realization. The carrying amounts of notes receivable, the term loan, and the revolving credit facility also approximated their estimated fair value as of September 30, 2020, and December 31, 2019. We estimate the fair value of our non-recourse property debt 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, collateral quality, and loan to value ratios on similarly encumbered apartment communities within our portfolio. We classify the fair value of our non-recourse property debt within Level 2 of the GAAP fair value hierarchy based on the significance of certain of the unobservable inputs used to estimate its fair value. The following table summarizes carrying value and fair value for our non-recourse property debt (in thousands): As of September 30, 2020 As of December 31, 2019 Carrying Value Fair Value Carrying Value Fair Value Non-recourse property debt $ 4,079,251 $ 4,206,702 $ 4,251,339 $ 4,298,630

Variable Interest Entities

Variable Interest Entities	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Variable Interest Entities	Note 7 — Variable Interest Entities Consolidated Entities Aimco consolidates the Aimco Operating Partnership, a VIE of which Aimco is the primary beneficiary. Aimco, through the Aimco Operating Partnership, consolidates all VIEs for which it is the primary beneficiary. All of the VIEs the Aimco Operating Partnership consolidates own interests in one or more apartment communities and are typically structured to generate a return for their partners through the operation and ultimate sale of the communities. The Aimco Operating Partnership is the primary beneficiary in the limited partnerships in which it is the sole decision maker and has a substantial economic interest. The table below summarizes apartment community information regarding VIEs consolidated by the Aimco Operating Partnership, excluding 1001 Brickell Bay Drive as it is not an apartment community: September 30, 2020 December 31, 2019 VIEs with interests in apartment communities 6 6 Apartment communities owned by VIEs 17 6 Apartment homes in communities owned by VIEs 5,409 2,056 Assets of the Aimco Operating Partnership’s consolidated VIEs must first be used to settle the liabilities of such consolidated VIEs. These consolidated VIEs’ creditors do not have recourse to the general credit of the Aimco Operating Partnership. Assets and liabilities of VIEs, excluding those of the Aimco Operating Partnership, are summarized in the table below (in thousands): September 30, 2020 December 31, 2019 Assets (1) Net real estate $ 1,424,820 $ 501,272 Cash and cash equivalents 15,908 11,600 Restricted cash 8,648 2,063 Other assets 38,815 40,459 Liabilities (1) Non-recourse property debt, net, secured by Aimco communities 1,284,252 175,842 Deferred tax liability 136,968 147,722 Accrued liabilities and other 42,845 36,107 (1) VIEs as of September 30, 2020 and December 31, 2019, include one VIE that owns an interest in 1001 Brickell Bay Drive. Assets and liabilities include those of the VIE, but it is not included in the apartment counts above as it is not an apartment community. Unconsolidated Entities We have an interest in a partnership that owns Parkmerced Apartments, which meets the definition of a VIE. However, we are not the primary beneficiary and do not consolidate this partnership. We loaned $275.0 million to the partnership, which accrues interest at 10% per annum with a five-year five-year balance of $300.3 million, reflected in mezzanine investment in our condensed consolidated balance sheets, consists primarily of notes receivable and represents our maximum exposure to loss in this VIE.

Business Segments

Business Segments	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Business Segments	Note 8 — Business Segments We have three segments: (i) Same Store, (ii) Redevelopment and Development, and (iii) Acquisition and Other Real Estate. Our Same Store segment includes communities that have reached a stabilized level of operations as of the beginning of a two-year comparable period and maintained it throughout the current and comparable prior year and are not expected to be sold within 12 months. Our Redevelopment and Development segment includes apartment communities that are currently under construction, and those that have been completed in recent years that have not achieved and maintained stabilized operations for both the current and comparable prior year. Our Acquisition and Other Real Estate segment includes: (i) communities that we have acquired since the beginning of a two-year comparable period; (ii) communities that are subject to limitations on rent increases; (iii) communities that we expect to sell within 12 months but do not yet meet the criteria to be classified as held for sale; (iv) communities that we expect to redevelop; and (v) certain commercial spaces. Our chief operating decision maker uses proportionate property net operating income to assess the operating performance of our communities. Proportionate property net operating income reflects our share of rental and other property revenues, excluding utility reimbursements, less direct property operating expenses, net of utility reimbursements, for consolidated communities. In our condensed consolidated statements of operations, utility reimbursements are included in rental and other property revenues, in accordance with GAAP. As of September 30, 2020, our Same Store segment included 93 consolidated apartment communities with 27,610 apartment homes; our Redevelopment and Development segment included eight consolidated communities with 2,521 homes; and our Acquisition and Other Real Estate segment included 20 communities with 2,670 homes and one office building. The following tables present the rental and other property revenues, property operating expenses, proportionate property net operating income, and income before income tax benefit (expense) of our segments on a proportionate basis, excluding amounts related to communities sold or held for sale and our proportionate share of four apartment communities with 142 apartment homes that we neither manage nor consolidate, for the three and nine months ended September 30, 2020 and 2019 (in thousands): Same Store Redevelopment and Development Acquisition and Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Three months ended September 30, 2020: Rental and other property revenues $ 171,033 $ 12,498 $ 17,311 $ 12,531 $ 2,082 $ 215,455 Property operating expenses 49,146 4,919 7,103 9,706 4,055 74,929 Other operating expenses not allocated to segments (3) — — — — 126,757 126,757 Total operating expenses 49,146 4,919 7,103 9,706 130,812 201,686 Proportionate property net operating income (loss) 121,887 7,579 10,208 2,825 (128,730 ) 13,769 Other items included in income before income tax benefit (4) — — — — (40,331 ) (40,331 ) Income (loss) before income tax benefit $ 121,887 $ 7,579 $ 10,208 $ 2,825 $ (169,061 ) $ (26,562 ) Same Store Redevelopment and Development Acquisition and Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Three months ended September 30, 2019: Rental and other property revenues $ 183,552 $ 11,131 $ 18,670 $ 8,390 $ 8,084 $ 229,827 Property operating expenses 50,424 4,484 6,862 7,790 7,924 77,484 Other operating expenses not allocated to segments (3) — — — — 113,716 113,716 Total operating expenses 50,424 4,484 6,862 7,790 121,640 191,200 Proportionate property net operating income (loss) 133,128 6,647 11,808 600 (113,556 ) 38,627 Other items included in income before income tax benefit (4) — — — — (37,753 ) (37,753 ) Income (loss) before income tax benefit $ 133,128 $ 6,647 $ 11,808 $ 600 $ (151,309 ) $ 874 Same Store Redevelopment and Development Acquisition and Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Nine months ended September 30, 2020: Rental and other property revenues $ 534,395 $ 36,001 $ 53,485 $ 29,668 $ 5,266 $ 658,815 Property operating expenses 145,259 14,636 20,045 25,617 18,975 224,532 Other operating expenses not allocated to segments (3) — — — — 352,912 352,912 Total operating expenses 145,259 14,636 20,045 25,617 371,887 577,444 Proportionate property net operating income (loss) 389,136 21,365 33,440 4,051 (366,621 ) 81,371 Other items included in income before income tax benefit (4) — — — — (61,864 ) (61,864 ) Income (loss) before income tax benefit $ 389,136 $ 21,365 $ 33,440 $ 4,051 $ (428,485 ) $ 19,507 Same Store Redevelopment and Development Acquisition and Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Nine months ended September 30, 2019: Rental and other property revenues $ 542,624 $ 37,839 $ 46,881 $ 24,389 $ 32,529 $ 684,262 Property operating expenses 146,895 14,736 17,403 22,704 30,352 232,090 Other operating expenses not allocated to segments (3) — — — — 332,027 332,027 Total operating expenses 146,895 14,736 17,403 22,704 362,379 564,117 Proportionate property net operating income (loss) 395,729 23,103 29,478 1,685 (329,850 ) 120,145 Other items included in income before income tax benefit (4) — — — — 243,174 243,174 Income (loss) before income tax benefit $ 395,729 $ 23,103 $ 29,478 $ 1,685 $ (86,676 ) $ 363,319 (1) Represents adjustments for the noncontrolling interests in consolidated real estate partnerships’ share of the results of consolidated communities in our segments, which are included in the related consolidated 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 in our condensed consolidated statements of operations prepared in accordance with GAAP. (2) Includes the operating results of apartment communities sold during the periods shown or held for sale at the end of the period, if any. Also includes property management expenses and casualty gains and losses, which are included in consolidated property operating expenses and are not part of our segment performance measure. The write-off of straight-line rent receivables, recognized due to the impact of COVID-19 and the resulting economic impact on our commercial tenants, are included in consolidated rental and property revenues and are not included in our measurement of segment performance for the three and nine months ended September 30, 2020. (3) Includes depreciation and amortization, general and administrative expenses, and other operating expenses, which may include provision for real estate impairment loss and write-offs of deferred leasing commissions, which are not included in our measure of segment performance. (4) Includes gain on dispositions of real estate, mezzanine investment income, income from unconsolidated communities, interest income, and interest expense. The assets of our segments and the consolidated assets not allocated to our segments were as follows (in thousands): September 30, 2020 December 31, 2019 Same Store $ 4,491,989 $ 4,618,108 Redevelopment and Development 859,214 716,750 Acquisition and Other Real Estate 881,824 803,777 Corporate and other assets (1) 809,102 690,104 Total consolidated assets $ 7,042,129 $ 6,828,739 (1) Includes the assets not allocated to our segments, primarily corporate assets, our mezzanine investment, and assets of communities sold or held for sale as of September 30, 2020. For the nine months ended September 30, 2020 and 2019, capital additions related to our segments were as follows (in thousands): 2020 2019 Same Store $ 73,681 $ 130,967 Redevelopment and Development 168,247 144,210 Acquisition and Other Real Estate 18,796 25,160 Total capital additions $ 260,724 $ 300,337

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	Note 9 – Subsequent Events On October 21, 2020, our Board of Directors declared a $8.20 special dividend in the form of cash and stock. The special dividend includes the next two quarterly cash dividends, or $0.82 per share in the aggregate, accelerating the payment of the regular dividend expected in February of 2021. Additionally, shareholders in the aggregate will receive $7.38 per share in stock. The dividend will be payable to shareholders of record on the close of business on November 4, 2020, with shareholders having the opportunity to elect to receive the special dividend in the form of all stock or prorated cash and stock, and will be paid on November 30, 2020, after trading hours. The number of shares distributed in the special dividend will be determined by the volume weighted average price (“VWAP”) of our shares during the 10-trading day period ending on November 24, 2020. In order to neutralize the dilutive impact of the stock issued in the special dividend, our Board also authorized a reverse stock split, effective on November 30, 2020, immediately following the special dividend. As a result, total shares outstanding following completion of both the special dividend and the reverse stock split are expected to be unchanged from the total shares outstanding immediately prior to the dividend. Some stockholders may have more shares and some may have fewer based on their individual elections. The reverse split will ensure comparability of per share results before and after these transactions.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Certain information and footnote disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted in accordance with such rules and regulations, although management believes the disclosures are adequate to prevent the information presented from being misleading. In the opinion of management, all adjustments, consisting of normal recurring items, considered necessary for a fair presentation have been included. Operating results for the three and nine months ended September 30, 2020, are not necessarily indicative of the results that may be expected for the year ending December 31, 2020. The condensed consolidated balance sheets of Aimco and the Aimco Operating Partnership as of December 31, 2019 , have been derived from their respective audited financial statements at that date, but do not include all of the information and disclosures required by GAAP for complete financial statements. For further information, refer to the financial statements and notes thereto included in Aimco’s and the Aimco Operating Partnership’s combined Annual Report on Form 10-K for the year ended December 31, 2019 . Except where indicated, the footnotes refer to both Aimco and the Aimco Operating Partnership.
Principles of Consolidation	Principles of Consolidation Aimco’s accompanying condensed consolidated financial statements include the accounts of Aimco, the Aimco Operating Partnership, and their consolidated subsidiaries. The Aimco Operating Partnership’s condensed consolidated financial statements include the accounts of the Aimco Operating Partnership and its consolidated subsidiaries. All significant intercompany balances and transactions have been eliminated in consolidation. We consolidate a variable interest entity, or 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. Interests in the Aimco Operating Partnership that are held by limited partners other than Aimco are reflected in Aimco’s accompanying condensed consolidated balance sheets as noncontrolling interests in the Aimco Operating Partnership. Interests in partnerships consolidated by the Aimco Operating Partnership that are held by third parties are reflected in our accompanying condensed consolidated balance sheets as noncontrolling interests in consolidated real estate partnerships.
Redeemable Preferred OP Units	Redeemable Preferred OP Units As described in Note 5, the preferred OP Units may be redeemed at the holder’s option and are therefore presented within temporary equity in Aimco’s condensed consolidated balance sheets and within temporary capital in the Aimco Operating Partnership’s condensed consolidated balance sheets. The following table presents a reconciliation of the Aimco Operating Partnership’s preferred OP Units from December 31, 2019, to September 30, 2020 (in thousands): Balance at December 31, 2019 $ 97,064 Preferred distributions (5,415 ) Redemption of preferred units (17,615 ) Net income 5,415 Balance at September 30, 2020 $ 79,449 The Aimco Operating Partnership has outstanding various classes of redeemable preferred OP Units. As of September 30, 2020 and December 31, 2019, the Aimco Operating Partnership had 2,938,802 and 3,643,399 redeemable preferred OP Units, respectively, issued and outstanding. Distributions per annum range from 1.92% to 8.75% per class and $0.48 to $8.00 per unit.
Revenue from Leases	Revenue from Leases The majority of lease payments we receive from our residents and tenants are fixed. We receive variable payments from our residents and commercial tenants primarily for utility reimbursements. For the three and nine months ended September 30, 2020 and 2019, our total lease income was comprised of the following amounts for all operating leases (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Fixed lease income $ 200,295 $ 213,945 $ 619,447 $ 639,359 Variable lease income 14,578 15,005 40,842 42,814 Straight-line rent write-off (1) — — (2,927 ) — Total lease income $ 214,873 $ 228,950 $ 657,362 $ 682,173 (1) We monitor the collectability of all unpaid rent amounts. The onset of COVID-19 and the anticipated economic slowdown resulted in a $2.9 million write-off of accrued straight-line rent during the nine months ended September 30, 2020. Additionally, we wrote-off the related deferred leasing costs of $2.4 million during the nine months ended September 30, 2020. The write-offs of deferred leasing costs are recorded in depreciation and amortization in our condensed consolidated statements of operations. In response to the economic effects of the COVID-19 pandemic and government al lockdown , many jurisdictions where our communities are located have enacted protections for residents and commercial tenants, including government - mandated rent deferrals, rent freezes, repayment extensions, fee abatement measures or concessions, and prohibitions on lease terminations or evictions for tenants . Some states and municipalities are also implementing rental assistance programs and encouraging landlord - tenant negotiations . On April 10, 2020, the Financial Accounting Standards Board, or FASB, issued a Staff Q&A to respond to some frequently asked questions about accounting for lease concessions, including deferrals or reductions of future lease payments. Consequently, in accordance with the Staff Q&A issued by the FASB, we may elect to record rent relief when granted rather than over the remaining term of the lease. Our residential tenants represent approximately 97% of revenue and our commercial tenants represent approximately 3% of revenue for the three months ended September 30, 2020. For the three and nine months ended September 30, 2020, we granted to commercial tenants $0.6 million and $1.0 million in rent relief, respectively, and elected to record these as a reduction of variable lease income in the table above.
Use of Estimates	Use of Estimates The preparation of our condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts included in the financial statements and accompanying notes thereto. Actual results could differ from those estimates.
Reclassifications and Revisions	Reclassifications and Revisions For the 2020 presentation of our condensed consolidated statements of operations, we have added a caption for investment management expenses. We have reclassified certain items from property operating expenses, general and administrative expenses, and other expenses, net, in our 2019 presentation to conform to the current presentation.
Accounting Pronouncements Adopted in the Current Year	Accounting Pronouncements Adopted in the Current Year On January 1, 2020, we adopted ASC 326, Financial Instruments – Credit Losses We adopted the credit loss standard using the modified-retrospective approach. We recorded a cumulative-effect adjustment for the estimated credit loss associated with our notes receivable of $0.3 million in distributions in excess of earnings and partners’ capital in our condensed consolidated balance sheets as of January 1, 2020. As of the date of adoption, the fair value of our AFS debt securities exceeded their carrying value and no estimate of credit loss was required for these instruments.
Fair Value of Financial Instruments	Recurring Fair Value Measurements

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Reconciliation of Preferred OP Units	As described in Note 5, the preferred OP Units may be redeemed at the holder’s option and are therefore presented within temporary equity in Aimco’s condensed consolidated balance sheets and within temporary capital in the Aimco Operating Partnership’s condensed consolidated balance sheets. The following table presents a reconciliation of the Aimco Operating Partnership’s preferred OP Units from December 31, 2019, to September 30, 2020 (in thousands): Balance at December 31, 2019 $ 97,064 Preferred distributions (5,415 ) Redemption of preferred units (17,615 ) Net income 5,415 Balance at September 30, 2020 $ 79,449
Lease Income for Operating Leases	The majority of lease payments we receive from our residents and tenants are fixed. We receive variable payments from our residents and commercial tenants primarily for utility reimbursements. For the three and nine months ended September 30, 2020 and 2019, our total lease income was comprised of the following amounts for all operating leases (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Fixed lease income $ 200,295 $ 213,945 $ 619,447 $ 639,359 Variable lease income 14,578 15,005 40,842 42,814 Straight-line rent write-off (1) — — (2,927 ) — Total lease income $ 214,873 $ 228,950 $ 657,362 $ 682,173 (1) We monitor the collectability of all unpaid rent amounts. The onset of COVID-19 and the anticipated economic slowdown resulted in a $2.9 million write-off of accrued straight-line rent during the nine months ended September 30, 2020. Additionally, we wrote-off the related deferred leasing costs of $2.4 million during the nine months ended September 30, 2020. The write-offs of deferred leasing costs are recorded in depreciation and amortization in our condensed consolidated statements of operations.

Significant Transactions (Table

Significant Transactions (Tables)	9 Months Ended
	Sep. 30, 2020
Asset Acquisitions [Member]
Summarized Information Regarding Acquisition	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 this acquisition is set forth in the table below (dollars in thousands): Number of apartment homes 271 Purchase price $ 89,600 Capitalized transaction costs 2,506 Total consideration $ 92,106 Consideration allocated to land $ 56,251 Consideration allocated to building and improvements 34,645 Consideration allocated to intangible assets (1) 1,506 Consideration allocated to below-market lease liabilities (2) (296 ) Total consideration $ 92,106 (1) Intangible assets include in-place leases and leasing costs with a weighted-average term of 0.5 (2) Below-market leases have a weighted-average term of 0.8

Earnings and Dividends per Sh_2

Earnings and Dividends per Share and Unit (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Schedule of Calculations of Basic and Diluted Earnings per Share and per Unit and Non-dilutive Securities	Reconciliations of the numerator and denominator in the calculations of basic and diluted earnings per share and per unit for the three and nine months ended September 30, 2020 and 2019, are as follows (in thousands, except per share and per unit data): Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Earnings per share Numerator: Basic and dilutive net (loss) income attributable to Aimco common stockholders $ (25,046 ) $ 2,003 $ 20,845 $ 332,805 Denominator – shares: Basic weighted-average Common Stock outstanding 148,544 148,434 148,532 147,474 Dilutive share equivalents outstanding — 202 96 218 Dilutive weighted-average Common Stock outstanding 148,544 148,636 148,628 147,692 Earnings per share – basic and diluted $ (0.17 ) $ 0.01 $ 0.14 $ 2.26 Non-dilutive share equivalents outstanding 9,007 — 8,337 — Earnings per unit Numerator: Basic and dilutive net (loss) income attributable to the Aimco Operating Partnership's common unitholders $ (26,387 ) $ 2,138 $ 21,979 $ 351,594 Denominator – units Basic weighted-average common partnership units outstanding 156,508 156,618 156,559 155,644 Dilutive partnership unit equivalents outstanding — 261 133 327 Dilutive weighted-average common partnership units outstanding 156,508 156,879 156,692 155,971 Earnings per unit – basic and diluted $ (0.17 ) $ 0.01 $ 0.14 $ 2.26 Non-dilutive partnership unit equivalents outstanding 2,220 — 1,596 —
Summary of Dividend and Distribution Paid per Unit	Dividends and distributions paid during the three and nine months ended September 30, 2020 and 2019, were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Dividends and distributions paid $ 0.41 $ 0.39 $ 1.23 $ 2.80 Aimco Special Dividend: Cash $ 67.1 Shares of Common Stock 4.5 Cash paid in lieu of issuing fractional shares $ 0.4 Aimco Operating Partnership Special Distribution: Cash $ 72.7 Common partnership units 4.8 Cash paid in lieu of issuing fractional units $ 0.4

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Summary of Fair Value for AFS Debt Securities and Derivative Instrument	The following table summarizes fair value for our AFS debt securities and our interest rate option (in thousands): As of September 30, 2020 As of December 31, 2019 Total Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 AFS debt securities $ 98,874 $ — $ 98,874 $ — $ 94,251 $ — $ 94,251 $ — Interest rate option 10,026 — 10,026 — — — — —
Summary of Carrying Value and Fair Value of Non-recourse Property Debt	The following table summarizes carrying value and fair value for our non-recourse property debt (in thousands): As of September 30, 2020 As of December 31, 2019 Carrying Value Fair Value Carrying Value Fair Value Non-recourse property debt $ 4,079,251 $ 4,206,702 $ 4,251,339 $ 4,298,630

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	9 Months Ended
	Sep. 30, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Variable Interest Entities	The table below summarizes apartment community information regarding VIEs consolidated by the Aimco Operating Partnership, excluding 1001 Brickell Bay Drive as it is not an apartment community: September 30, 2020 December 31, 2019 VIEs with interests in apartment communities 6 6 Apartment communities owned by VIEs 17 6 Apartment homes in communities owned by VIEs 5,409 2,056 Assets of the Aimco Operating Partnership’s consolidated VIEs must first be used to settle the liabilities of such consolidated VIEs. These consolidated VIEs’ creditors do not have recourse to the general credit of the Aimco Operating Partnership. Assets and liabilities of VIEs, excluding those of the Aimco Operating Partnership, are summarized in the table below (in thousands): September 30, 2020 December 31, 2019 Assets (1) Net real estate $ 1,424,820 $ 501,272 Cash and cash equivalents 15,908 11,600 Restricted cash 8,648 2,063 Other assets 38,815 40,459 Liabilities (1) Non-recourse property debt, net, secured by Aimco communities 1,284,252 175,842 Deferred tax liability 136,968 147,722 Accrued liabilities and other 42,845 36,107 (1) VIEs as of September 30, 2020 and December 31, 2019, include one VIE that owns an interest in 1001 Brickell Bay Drive. Assets and liabilities include those of the VIE, but it is not included in the apartment counts above as it is not an apartment community. Unconsolidated Entities We have an interest in a partnership that owns Parkmerced Apartments, which meets the definition of a VIE. However, we are not the primary beneficiary and do not consolidate this partnership. We loaned $275.0 million to the partnership, which accrues interest at 10% per annum with a five-year five-year balance of $300.3 million, reflected in mezzanine investment in our condensed consolidated balance sheets, consists primarily of notes receivable and represents our maximum exposure to loss in this VIE.

Business Segments (Tables)

Business Segments (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Summary of Information for Reportable Segments	The following tables present the rental and other property revenues, property operating expenses, proportionate property net operating income, and income before income tax benefit (expense) of our segments on a proportionate basis, excluding amounts related to communities sold or held for sale and our proportionate share of four apartment communities with 142 apartment homes that we neither manage nor consolidate, for the three and nine months ended September 30, 2020 and 2019 (in thousands): Same Store Redevelopment and Development Acquisition and Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Three months ended September 30, 2020: Rental and other property revenues $ 171,033 $ 12,498 $ 17,311 $ 12,531 $ 2,082 $ 215,455 Property operating expenses 49,146 4,919 7,103 9,706 4,055 74,929 Other operating expenses not allocated to segments (3) — — — — 126,757 126,757 Total operating expenses 49,146 4,919 7,103 9,706 130,812 201,686 Proportionate property net operating income (loss) 121,887 7,579 10,208 2,825 (128,730 ) 13,769 Other items included in income before income tax benefit (4) — — — — (40,331 ) (40,331 ) Income (loss) before income tax benefit $ 121,887 $ 7,579 $ 10,208 $ 2,825 $ (169,061 ) $ (26,562 ) Same Store Redevelopment and Development Acquisition and Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Three months ended September 30, 2019: Rental and other property revenues $ 183,552 $ 11,131 $ 18,670 $ 8,390 $ 8,084 $ 229,827 Property operating expenses 50,424 4,484 6,862 7,790 7,924 77,484 Other operating expenses not allocated to segments (3) — — — — 113,716 113,716 Total operating expenses 50,424 4,484 6,862 7,790 121,640 191,200 Proportionate property net operating income (loss) 133,128 6,647 11,808 600 (113,556 ) 38,627 Other items included in income before income tax benefit (4) — — — — (37,753 ) (37,753 ) Income (loss) before income tax benefit $ 133,128 $ 6,647 $ 11,808 $ 600 $ (151,309 ) $ 874 Same Store Redevelopment and Development Acquisition and Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Nine months ended September 30, 2020: Rental and other property revenues $ 534,395 $ 36,001 $ 53,485 $ 29,668 $ 5,266 $ 658,815 Property operating expenses 145,259 14,636 20,045 25,617 18,975 224,532 Other operating expenses not allocated to segments (3) — — — — 352,912 352,912 Total operating expenses 145,259 14,636 20,045 25,617 371,887 577,444 Proportionate property net operating income (loss) 389,136 21,365 33,440 4,051 (366,621 ) 81,371 Other items included in income before income tax benefit (4) — — — — (61,864 ) (61,864 ) Income (loss) before income tax benefit $ 389,136 $ 21,365 $ 33,440 $ 4,051 $ (428,485 ) $ 19,507 Same Store Redevelopment and Development Acquisition and Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Nine months ended September 30, 2019: Rental and other property revenues $ 542,624 $ 37,839 $ 46,881 $ 24,389 $ 32,529 $ 684,262 Property operating expenses 146,895 14,736 17,403 22,704 30,352 232,090 Other operating expenses not allocated to segments (3) — — — — 332,027 332,027 Total operating expenses 146,895 14,736 17,403 22,704 362,379 564,117 Proportionate property net operating income (loss) 395,729 23,103 29,478 1,685 (329,850 ) 120,145 Other items included in income before income tax benefit (4) — — — — 243,174 243,174 Income (loss) before income tax benefit $ 395,729 $ 23,103 $ 29,478 $ 1,685 $ (86,676 ) $ 363,319 (1) Represents adjustments for the noncontrolling interests in consolidated real estate partnerships’ share of the results of consolidated communities in our segments, which are included in the related consolidated 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 in our condensed consolidated statements of operations prepared in accordance with GAAP. (2) Includes the operating results of apartment communities sold during the periods shown or held for sale at the end of the period, if any. Also includes property management expenses and casualty gains and losses, which are included in consolidated property operating expenses and are not part of our segment performance measure. The write-off of straight-line rent receivables, recognized due to the impact of COVID-19 and the resulting economic impact on our commercial tenants, are included in consolidated rental and property revenues and are not included in our measurement of segment performance for the three and nine months ended September 30, 2020. (3) Includes depreciation and amortization, general and administrative expenses, and other operating expenses, which may include provision for real estate impairment loss and write-offs of deferred leasing commissions, which are not included in our measure of segment performance. (4) Includes gain on dispositions of real estate, mezzanine investment income, income from unconsolidated communities, interest income, and interest expense.
Reconciliation of Assets from Segment to Consolidated	The assets of our segments and the consolidated assets not allocated to our segments were as follows (in thousands): September 30, 2020 December 31, 2019 Same Store $ 4,491,989 $ 4,618,108 Redevelopment and Development 859,214 716,750 Acquisition and Other Real Estate 881,824 803,777 Corporate and other assets (1) 809,102 690,104 Total consolidated assets $ 7,042,129 $ 6,828,739 (1) Includes the assets not allocated to our segments, primarily corporate assets, our mezzanine investment, and assets of communities sold or held for sale as of September 30, 2020.
Capital Additions Related to Segments	For the nine months ended September 30, 2020 and 2019, capital additions related to our segments were as follows (in thousands): 2020 2019 Same Store $ 73,681 $ 130,967 Redevelopment and Development 168,247 144,210 Acquisition and Other Real Estate 18,796 25,160 Total capital additions $ 260,724 $ 300,337

Organization (Details Textual)

Organization (Details Textual) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020USD ($)Propertyapartment_homeMulti_family_apartmentshares	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)Propertyapartment_homeMulti_family_apartmentshares	Sep. 30, 2019USD ($)
Organization [Line Items]
Other expenses, net | $	$ 17,571	$ 4,002	$ 23,452	$ 12,759
Separation Costs [Member]
Organization [Line Items]
Other expenses, net | $	$ 11,900		$ 12,600
Partially Owned Properties [Member]
Organization [Line Items]
Number of apartment communities | Property	126		126
Number of apartment homes in apartment communities | apartment_home	33,209		33,209
Percentage of average ownership of portfolio	95.00%		95.00%
Wholly And Partially Owned Consolidated Properties [Member]
Organization [Line Items]
Number of apartment communities | Property	122		122
Number of apartment homes in apartment communities | apartment_home	33,067		33,067
Aimco Post Separation [Member]
Organization [Line Items]
Number of apartment communities | Property	25		25
Separate entity as percentage of portfolio NAV			10.00%
AIMCO PROPERTIES, L.P [Member]
Organization [Line Items]
Common operating partnership units and equivalents outstanding | shares	159,182,513		159,182,513
Common operating partnership units and equivalents outstanding | shares	148,865,947		148,865,947
Percentage of the Aimco Operating Partnership's common partnership units and equivalents owned by Aimco			93.50%
Percentage of economic interest			94.90%
Apartment Income REIT [Member]
Organization [Line Items]
Separations beginning date			Sep. 14, 2020
Separate entity as percentage of portfolio NAV			90.00%
Apartment Income REIT [Member] | Aimco Post Separation [Member] | Multi-Family Communities Securing Note Payable [Member]
Organization [Line Items]
Number of apartment communities | Multi_family_apartment	16		16
Apartment Income REIT [Member] | Aimco Post Separation [Member] | Note Payable Secured by Multi-Family Communities [Member]
Organization [Line Items]
Notes payable | $	$ 534,000		$ 534,000

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Reconciliation of Preferred OP Units (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance at December 31, 2019	$ 97,064
Balance at September 30, 2020	79,449
AIMCO PROPERTIES, L.P [Member]
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance at December 31, 2019	97,064
Preferred distributions	(5,415)
Redemption of preferred units	(17,615)
Net income	5,415
Balance at September 30, 2020	$ 79,449

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies (Details Textual) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Estimate of credit loss	$ 0	$ 0
Cumulative Effect, Period of Adoption, Adjustment | ASC 326 [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Cumulative effect adjustment for estimated credit loss	$ (300,000)	(300,000)
Residential [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Percentage of revenue represented by tenant	97.00%
Commercial [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Percentage of revenue represented by tenant	3.00%
Lease concession	$ 600,000	$ 1,000,000
AIMCO PROPERTIES, L.P [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Units issued (in shares)	2,938,802	2,938,802	3,643,399
Units outstanding (in shares)	2,938,802	2,938,802	3,643,399
AIMCO PROPERTIES, L.P [Member] | Minimum [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Distributions per annum (in dollars per share)		$ 0.48
Distributions per annum		1.92%
AIMCO PROPERTIES, L.P [Member] | Maximum [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Distributions per annum (in dollars per share)		$ 8
Distributions per annum		8.75%

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies - Lease Income for Operating Leases (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Fixed lease income		$ 200,295	$ 213,945	$ 619,447	$ 639,359
Variable lease income		14,578	15,005	40,842	42,814
Straight-line rent write-off	[1]			(2,927)
Total lease income		$ 214,873	$ 228,950	$ 657,362	$ 682,173
[1]	We monitor the collectability of all unpaid rent amounts. The onset of COVID-19 and the anticipated economic slowdown resulted in a $2.9 million write-off of accrued straight-line rent during the nine months ended September 30, 2020. Additionally, we wrote-off the related deferred leasing costs of $2.4 million during the nine months ended September 30, 2020. The write-offs of deferred leasing costs are recorded in depreciation and amortization in our condensed consolidated statements of operations.

Basis of Presentation and Sum_7

Basis of Presentation and Summary of Significant Accounting Policies - Lease Income for Operating Leases (Parenthetical) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Disaggregation Of Revenue [Line Items]
Write off of straight line rent receivables	$ 2,927	[1]
COVID Related Write-off [Member]
Disaggregation Of Revenue [Line Items]
Write off of straight line rent receivables	2,900
Deferred leasing costs	$ 2,400
[1]	We monitor the collectability of all unpaid rent amounts. The onset of COVID-19 and the anticipated economic slowdown resulted in a $2.9 million write-off of accrued straight-line rent during the nine months ended September 30, 2020. Additionally, we wrote-off the related deferred leasing costs of $2.4 million during the nine months ended September 30, 2020. The write-offs of deferred leasing costs are recorded in depreciation and amortization in our condensed consolidated statements of operations.

Significant Transactions (Detai

Significant Transactions (Details Textual) $ in Thousands	Dec. 31, 2020USD ($)apartment_home	Sep. 08, 2020USD ($)apartment_homeMulti_family_apartment$ / Home	Apr. 20, 2020USD ($)	Sep. 30, 2020USD ($)Propertyapartment_home	Sep. 30, 2019USD ($)Property	Sep. 30, 2020USD ($)Propertyapartment_home	Sep. 30, 2019USD ($)Propertyapartment_home
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Gain on dispositions of real estate				$ 0	$ 1,146	$ 47,204	$ 356,929
IQHQ [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Commitment purchase amount				$ 50,000
Term Loan [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Secured term loan			$ 350,000
Term loan maturity date			Apr. 20, 2021
Term loan option to extend			1 year
Variable interest rate description			currently bears interest at a 30-day LIBOR plus 1.85%, with a 50-basis point LIBOR floor.
Term Loan [Member] | 30-Day LIBOR [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Spread on variable interest rate			1.85%
Term Loan [Member] | LIBOR Floor [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Spread on variable interest rate			0.50%
Wholly And Partially Owned Consolidated Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment communities | Property				122		122
Number of apartment homes in apartment communities | apartment_home				33,067		33,067
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Scenario Forecast [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Sales price for a property to be sold	$ 126,000
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Wholly And Partially Owned Consolidated Properties [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment communities sold | Property				0	0	1	8
Number of apartment homes sold | apartment_home						219	2,605
Gain on dispositions of real estate						$ 47,200	$ 356,900
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Scenario Forecast [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	266
Joint Venture Transaction
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of apartment communities | Multi_family_apartment		12
Number of apartment homes in apartment communities | apartment_home		4,051
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures		$ 2,400,000
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures | $ / Home		592,000
Secured term loan		$ 1,220,000
Implied equity value contributed by communities		1,180,000
Property debt		475,000
Investment owned amount		$ 461,000
Joint Venture Transaction | Ownership Exchanged [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Joint venture ownership percentage		39.00%
Joint Venture Transaction | Ownership Retained [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Joint venture ownership percentage retained		61.00%

Significant Transactions - Summ

Significant Transactions - Summarized Information Regarding Acquisition (Details) $ in Thousands	Aug. 25, 2020USD ($)apartment_home	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Business Acquisition [Line Items]
Land		$ 1,891,763	$ 1,869,048
Buildings and improvements		$ 7,006,395	$ 6,868,543
Asset Acquisitions [Member]
Business Acquisition [Line Items]
Number of apartment homes in apartment communities | apartment_home	271
Purchase price	$ 89,600
Capitalized transaction costs	2,506
Total consideration	92,106
Land	56,251
Buildings and improvements	34,645
Consideration allocated to intangible assets	1,506
Consideration allocated to below-market lease liabilities	$ (296)

Significant Transactions - Su_2

Significant Transactions - Summarized Information Regarding Acquisition (Parenthetical) (Details)	9 Months Ended
	Sep. 30, 2020
In-place lease intangible assets
Business Acquisition [Line Items]
Acquired intangible assets, weighted average useful life	6 months
Below Market Leases
Business Acquisition [Line Items]
Acquired intangible assets, weighted average useful life	9 months 18 days

Commitments and Contingencies (

Commitments and Contingencies (Details Textual) $ in Millions	1 Months Ended	9 Months Ended
	May 31, 2017Party	Sep. 30, 2020USD ($)
Long-term Purchase Commitment [Line Items]
Number of potentially-responsible parties | Party	4
Commitments related to development, redevelopment and capital improvement activities [Member]
Long-term Purchase Commitment [Line Items]
Commitments related to capital spending activities | $		$ 184
Time Period of Long-term Purchase Commitment		12 months
Commitments related to operations [Member] | Maximum [Member]
Long-term Purchase Commitment [Line Items]
Time Period of Long-term Purchase Commitment		1 year

Earnings and Dividends per Sh_3

Earnings and Dividends per Share and Unit - Schedule of Calculations of Basic and Diluted Earnings per Share and per Unit and Non-dilutive Securities (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Earnings Per Share and Dividends Per Share [Line Items]
Basic and dilutive net (loss) income attributable to Aimco common stockholders	$ (25,046)	$ 2,003	$ 20,845	$ 332,805
Basic weighted-average Common Stock outstanding	148,544	148,434	148,532	147,474
Dilutive share equivalents outstanding		202	96	218
Dilutive weighted-average Common Stock outstanding	148,544	148,636	148,628	147,692
Net income attributable to Aimco per common share – basic and diluted	$ (0.17)	$ 0.01	$ 0.14	$ 2.26
Non-dilutive share equivalents outstanding	9,007		8,337
AIMCO Properties, LP [Member]
Schedule of Earnings Per Share and Dividends Per Share [Line Items]
Basic and dilutive net (loss) income attributable to Aimco common stockholders	$ (26,387)	$ 2,138	$ 21,979	$ 351,594
Basic weighted-average Common Stock outstanding	156,508	156,618	156,559	155,644
Dilutive share equivalents outstanding		261	133	327
Dilutive weighted-average Common Stock outstanding	156,508	156,879	156,692	155,971
Net income attributable to Aimco per common share – basic and diluted	$ (0.17)	$ 0.01	$ 0.14	$ 2.26
Non-dilutive share equivalents outstanding	2,220		1,596

Earnings and Dividends per Sh_4

Earnings and Dividends per Share and Unit (Details Textual) shares in Millions	3 Months Ended
	Mar. 31, 2019$ / shares	Sep. 30, 2020shares
Schedule of Earnings Per Share and Dividends Per Share [Line Items]
Number of shares potentially redeemable for (in shares) | shares		2.4
Equity reverse stock split	1.03119
Special Dividend and Special Distribution [Member]
Schedule of Earnings Per Share and Dividends Per Share [Line Items]
Dividends and distributions paid | $ / shares	$ 2.02

Earnings and Dividends per Sh_5

Earnings and Dividends per Share and Unit - Summary of Dividend and Distribution Paid per Unit (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Dividends and distributions paid	$ 0.41	$ 0.39	$ 1.23	$ 2.80

Earnings and Dividends per Sh_6

Earnings and Dividends per Share and Unit - Summary of Special Dividend and Distribution (Details) - USD ($) $ in Thousands, shares in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Distribution Made To Limited Partner [Line Items]
Cash	$ 61,034	$ 58,065		$ 182,893	$ 183,579
AIMCO Properties, LP [Member]
Distribution Made To Limited Partner [Line Items]
Cash	64,377	61,345		192,734	193,406
AIMCO Properties, LP [Member] | General Partner and Special Limited Partner [Member]
Distribution Made To Limited Partner [Line Items]
Cash	$ 61,034	$ 58,065		$ 182,893	$ 183,579
Special Distribution Paid [Member] | AIMCO Properties, LP [Member] | General Partner and Special Limited Partner [Member]
Distribution Made To Limited Partner [Line Items]
Cash			$ 72,700
Common partnership units			4.8
Cash paid in lieu of issuing fractional units			$ 400
Special Dividend Paid [Member]
Distribution Made To Limited Partner [Line Items]
Cash			$ 67,100
Shares of Common Stock			4.5
Cash paid in lieu of issuing fractional shares			$ 400

Fair Value Measurements (Detail

Fair Value Measurements (Details Textual) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized cost of the investment in available-for-sale debt securities	$ 95.3	$ 90
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 limited 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.
Interest Rate Option [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Payments for purchase of swaption	$ 12.1
Derivative strike rate	1.68%
Derivative strike rate for limited settlement	2.78%
Available-for-sale Securities [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face amount of investment in available-for-sale debt securities	$ 100.9
Expected remaining term of available for sale securities	9 months 18 days

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Fair Value for AFS Debt Securities and Derivative Instrument (Details) - Fair value recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	$ 98,874	$ 94,251
Interest rate option	10,026	0
Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	0	0
Interest rate option	0	0
Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	98,874	94,251
Interest rate option	10,026	0
Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	0	0
Interest rate option	$ 0	$ 0

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	Sep. 30, 2020	Dec. 31, 2019
Carrying Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Non-recourse property debt	$ 4,079,251	$ 4,251,339
Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Non-recourse property debt	$ 4,206,702	$ 4,298,630

Variable Interest Entities (Det

Variable Interest Entities (Details) $ in Thousands	Sep. 30, 2020USD ($)PropertyEntityUnit	Dec. 31, 2019USD ($)PropertyEntityUnit
Net real estate	$ 6,039,984	$ 6,019,307
Cash and cash equivalents	228,368	142,902
Restricted cash	40,123	34,800
Other assets	383,298	351,472
Non-recourse property debt, net, secured by Aimco communities	4,058,295	4,230,590
Accrued liabilities and other	$ 356,538	$ 360,574
Variable Interest Entity, Primary Beneficiary [Member]
VIEs with interests in apartment communities | Entity	6	6
Number of apartment communities | Property	17	6
Number of apartment homes in apartment communities | Unit	5,409	2,056
Net real estate	$ 1,424,820	$ 501,272
Cash and cash equivalents	15,908	11,600
Restricted cash	8,648	2,063
Other assets	38,815	40,459
Non-recourse property debt, net, secured by Aimco communities	1,284,252	175,842
Deferred tax liability	136,968	147,722
Accrued liabilities and other	$ 42,845	$ 36,107

Variable Interest Entities (Par

Variable Interest Entities (Parenthetical) (Details) - Entity	Sep. 30, 2020	Dec. 31, 2019
1001 Brickell Bay Drive [Member]
Number of VIE	1	1

Variable Interest Entities (D_2

Variable Interest Entities (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Mezzanine investment	$ 300,326	$ 280,258
Parkmerced Investment [Member]
Schedule Of Investment Income Reported Amounts By Category [Line Items]
Investment owned amount	$ 275,000
Equity method investment, interest rate percentage	10.00%
Equity method investment, term	5 years
Equity method investment, right to extend term	5 years
Mezzanine investment	$ 300,300

Business Segments (Details Text

Business Segments (Details Textual)	9 Months Ended
	Sep. 30, 2020Propertyapartment_homeSegmentoffice_building
Business Segments (Textual) [Abstract]
Number of reportable segments | Segment	3
Wholly And Partially Owned Consolidated Properties [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	122
Number of apartment homes in apartment communities | apartment_home	33,067
Wholly And Partially Owned Consolidated Properties [Member] | Same Store [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	93
Number of apartment homes in apartment communities | apartment_home	27,610
Wholly And Partially Owned Consolidated Properties [Member] | Redevelopment and Development [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	8
Number of apartment homes in apartment communities | apartment_home	2,521
Wholly And Partially Owned Consolidated Properties [Member] | Acquisition and Other Real Estate [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	20
Number of apartment homes in apartment communities | apartment_home	2,670
Wholly And Partially Owned Consolidated Properties [Member] | Acquisition and Other Real Estate [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 apartment homes in apartment communities | apartment_home	142

Business Segments - Summary of

Business Segments - Summary of Information for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Summary information for the reportable segments
Rental and other property revenues	$ 215,455	$ 229,827	$ 658,815	$ 684,262
Property operating expenses	74,929	77,484	224,532	232,090
Other operating expenses not allocated to segments	126,757	113,716	352,912	332,027
Total operating expenses	201,686	191,200	577,444	564,117
Proportionate property net operating income (loss)	13,769	38,627	81,371	120,145
Other items included in income before income tax benefit (expense)	(40,331)	(37,753)	(61,864)	243,174
(Loss) income before income tax benefit	(26,562)	874	19,507	363,319
Segment Reconciling Items [Member]
Summary information for the reportable segments
Rental and other property revenues	12,531	8,390	29,668	24,389
Property operating expenses	9,706	7,790	25,617	22,704
Total operating expenses	9,706	7,790	25,617	22,704
Proportionate property net operating income (loss)	2,825	600	4,051	1,685
(Loss) income before income tax benefit	2,825	600	4,051	1,685
Corporate Non-Segment [Member]
Summary information for the reportable segments
Rental and other property revenues	2,082	8,084	5,266	32,529
Property operating expenses	4,055	7,924	18,975	30,352
Other operating expenses not allocated to segments	126,757	113,716	352,912	332,027
Total operating expenses	130,812	121,640	371,887	362,379
Proportionate property net operating income (loss)	(128,730)	(113,556)	(366,621)	(329,850)
Other items included in income before income tax benefit (expense)	(40,331)	(37,753)	(61,864)	243,174
(Loss) income before income tax benefit	(169,061)	(151,309)	(428,485)	(86,676)
Same Store [Member] | Operating Segments [Member]
Summary information for the reportable segments
Rental and other property revenues	171,033	183,552	534,395	542,624
Property operating expenses	49,146	50,424	145,259	146,895
Total operating expenses	49,146	50,424	145,259	146,895
Proportionate property net operating income (loss)	121,887	133,128	389,136	395,729
(Loss) income before income tax benefit	121,887	133,128	389,136	395,729
Redevelopment and Development [Member] | Operating Segments [Member]
Summary information for the reportable segments
Rental and other property revenues	12,498	11,131	36,001	37,839
Property operating expenses	4,919	4,484	14,636	14,736
Total operating expenses	4,919	4,484	14,636	14,736
Proportionate property net operating income (loss)	7,579	6,647	21,365	23,103
(Loss) income before income tax benefit	7,579	6,647	21,365	23,103
Acquisition and Other Real Estate [Member] | Operating Segments [Member]
Summary information for the reportable segments
Rental and other property revenues	17,311	18,670	53,485	46,881
Property operating expenses	7,103	6,862	20,045	17,403
Total operating expenses	7,103	6,862	20,045	17,403
Proportionate property net operating income (loss)	10,208	11,808	33,440	29,478
(Loss) income before income tax benefit	$ 10,208	$ 11,808	$ 33,440	$ 29,478

Business Segments - Reconciliat

Business Segments - Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Total assets	$ 7,042,129	$ 6,828,739
Corporate Non-Segment [Member]
Segment Reporting Information [Line Items]
Total assets	809,102	690,104
Same Store [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	4,491,989	4,618,108
Redevelopment and Development [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	859,214	716,750
Acquisition and Other Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	$ 881,824	$ 803,777

Business Segments - Capital Add

Business Segments - Capital Additions Related to Segments (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Capital additions	$ 260,724	$ 300,337
Same Store [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Capital additions	73,681	130,967
Redevelopment and Development [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Capital additions	168,247	144,210
Acquisition and Other Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Capital additions	$ 18,796	$ 25,160

Subsequent Events - Additional

Subsequent Events - Additional Information (Details) - Subsequent Event [Member]	Oct. 21, 2020$ / shares
Subsequent Event [Line Items]
Effective date of special dividend and reverse stock split	Nov. 30, 2020
Special Dividend Declared [Member]
Subsequent Event [Line Items]
Dividends declaration date	Oct. 21, 2020
Dividend declared per share	$ 8.20
Cash dividend per share declared	0.82
Common stock dividend per share declared	$ 7.38
Dividend payable record date	Nov. 4, 2020
Common stock trading period	10 days
Dividend record date	Nov. 24, 2020