Apartment Investment and Management (AIV) 10-K 24 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Document Information [Line Items]
Entity Registrant Name	APARTMENT INVESTMENT & MANAGEMENT CO
Entity Central Index Key	0000922864
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Shell Company	false
Trading Symbol	AIV
Entity File Number	1-13232
Entity Tax Identification Number	84-1259577
Entity Incorporation, State or Country Code	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		148,930,402
Title of 12(b) Security	Class A Common Stock (Apartment Investment and Management Company)
Security Exchange Name	NYSE
Document Annual Report	true
Document Transition Report	false
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 7.4
Documents Incorporated by Reference	Portions of Apartment Investment and Management Company’s definitive proxy statement to be issued in conjunction with Apartment Investment and Management Company’s annual meeting of stockholders to be held April 28, 2020, are incorporated by reference into Part III of this Annual Report.
AIMCO Properties, LP [Member]
Document Information [Line Items]
Entity Registrant Name	AIMCO PROPERTIES LP
Entity Central Index Key	0000926660
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	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 Incorporation, State or Country Code	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
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Buildings and improvements	$ 6,868,543	$ 6,552,065
Land	1,869,048	1,756,525
Total real estate	8,737,591	8,308,590
Accumulated depreciation	(2,718,284)	(2,585,115)
Net real estate	6,019,307	5,723,475
Cash and cash equivalents	142,902	36,858
Restricted cash	34,800	35,737
Mezzanine investment	280,258	0
Other assets	351,472	351,541
Assets held for sale	0	42,393
Total assets	6,828,739	6,190,004
LIABILITIES AND EQUITY
Non-recourse property debt, net	4,230,590	3,915,305
Revolving credit facility borrowings	275,000	160,360
Total indebtedness	4,505,590	4,075,665
Accrued liabilities and other	360,574	226,230
Liabilities related to assets held for sale	0	23,177
Total liabilities	4,866,164	4,325,072
Preferred noncontrolling interests/Redeemable Preferred Units	97,064	101,291
Redeemable noncontrolling interests in consolidated real estate partnership	4,716	0
Commitments and contingencies (Note 6)
Equity/Partners' Capital:
Perpetual preferred stock (Note 7)	0	125,000
Common Stock, $0.01 par value, 500,787,260 shares authorized, 148,885,197 and 144,623,034 shares issued/outstanding at December 31, 2019 and 2018, respectively	1,489	1,446
Additional paid-in capital	3,497,367	3,515,686
Accumulated other comprehensive income	4,195	4,794
Distributions in excess of earnings	(1,722,402)	(1,947,507)
Total Aimco equity	1,780,649	1,699,419
Noncontrolling interests in consolidated real estate partnerships	(3,296)	(2,967)
Common noncontrolling interests in Aimco Operating Partnership	83,442	67,189
Total equity	1,860,795	1,763,641
Total liabilities and equity	6,828,739	6,190,004
AIMCO Properties, LP [Member]
ASSETS
Buildings and improvements	6,868,543	6,552,065
Land	1,869,048	1,756,525
Total real estate	8,737,591	8,308,590
Accumulated depreciation	(2,718,284)	(2,585,115)
Net real estate	6,019,307	5,723,475
Cash and cash equivalents	142,902	36,858
Restricted cash	34,800	35,737
Mezzanine investment	280,258	0
Other assets	351,472	351,541
Assets held for sale	0	42,393
Total assets	6,828,739	6,190,004
LIABILITIES AND EQUITY
Non-recourse property debt, net	4,230,590	3,915,305
Revolving credit facility borrowings	275,000	160,360
Total indebtedness	4,505,590	4,075,665
Accrued liabilities and other	360,574	226,230
Liabilities related to assets held for sale	0	23,177
Total liabilities	4,866,164	4,325,072
Preferred noncontrolling interests/Redeemable Preferred Units	97,064	101,291
Redeemable noncontrolling interests in consolidated real estate partnership	4,716	0
Commitments and contingencies (Note 6)
Equity/Partners' Capital:
Preferred units (Note 7)	0	125,000
General Partner and Special Limited Partner	1,780,649	1,574,419
Limited Partners	83,442	67,189
Partners’ capital attributable to the Aimco Operating Partnership	1,864,091	1,766,608
Partners' Capital Attributable to Noncontrolling Interest	(3,296)	(2,967)
Total partners’ capital	1,860,795	1,763,641
Total liabilities and equity	$ 6,828,739	$ 6,190,004

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Common Stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common Stock, shares authorized (in shares)	500,787,260	500,787,260
Common Stock, shares issued (in shares)	148,885,197	144,623,034
Common Stock, shares outstanding (in shares)	148,885,197	144,623,034

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
REVENUES:
Total revenues	$ 914,294	$ 972,410	$ 1,005,437
OPERATING EXPENSES:
Depreciation and amortization	380,171	377,786	366,184
General and administrative expenses	47,037	46,268	43,657
Other expenses, net	19,092	3,778	11,148
Provision for real estate impairment loss	0	0	35,881
Total operating expenses	757,521	756,654	811,454
Interest income	11,424	10,914	8,332
Interest expense	(168,807)	(200,634)	(194,615)
Gain on dispositions of real estate and the Asset Management business	503,168	677,463	300,849
Mezzanine / Unconsolidated partnerships investment income, net	1,531	0	0
Income before income tax benefit	504,892	703,576	316,243
Income tax benefit (Note 10)	3,135	13,027	30,836
Net income	508,027	716,603	347,079
Noncontrolling interests:
Net income attributable to noncontrolling interests in consolidated real estate partnerships	(187)	(8,220)	(9,084)
Net income attributable to preferred noncontrolling interests in Aimco Operating Partnership	(7,708)	(7,739)	(7,764)
Net income attributable to common noncontrolling interests in Aimco Operating Partnership	(26,049)	(34,417)	(14,457)
Net income attributable to noncontrolling interests	(33,944)	(50,376)	(31,305)
Net income attributable to the company	474,083	666,227	315,774
Net income attributable to the company's preferred equity holders	(7,335)	(8,593)	(8,594)
Net income attributable to participating securities	(604)	(1,037)	(319)
Net income attributable to the company's common equity holders	$ 466,144	$ 656,597	$ 306,861
Net income attributable to Aimco per common share – basic	$ 3.16	$ 4.34	$ 2.02
Net income attributable to Aimco per common share – diluted	$ 3.15	$ 4.34	$ 2.02
Weighted average common shares/units outstanding - basic	147,718	151,152	151,595
Weighted average common shares/units outstanding - diluted	147,944	151,334	152,060
AIMCO Properties, LP [Member]
REVENUES:
Total revenues	$ 914,294	$ 972,410	$ 1,005,437
OPERATING EXPENSES:
Depreciation and amortization	380,171	377,786	366,184
General and administrative expenses	47,037	46,268	43,657
Other expenses, net	19,092	3,778	11,148
Provision for real estate impairment loss	0	0	35,881
Total operating expenses	757,521	756,654	811,454
Interest income	11,424	10,914	8,332
Interest expense	(168,807)	(200,634)	(194,615)
Gain on dispositions of real estate and the Asset Management business	503,168	677,463	300,849
Mezzanine / Unconsolidated partnerships investment income, net	1,531	0	0
Income before income tax benefit	504,892	703,576	316,243
Income tax benefit (Note 10)	3,135	13,027	30,836
Net income	508,027	716,603	347,079
Noncontrolling interests:
Net income attributable to noncontrolling interests in consolidated real estate partnerships	(187)	(8,220)	(9,084)
Net income attributable to the company	507,840	708,383	337,995
Net income attributable to the company's preferred equity holders	(15,043)	(16,332)	(16,358)
Net income attributable to participating securities	(620)	(1,177)	(337)
Net income attributable to the company's common equity holders	$ 492,177	$ 690,874	$ 321,300
Net income attributable to Aimco per common share – basic	$ 3.16	$ 4.35	$ 2.02
Net income attributable to Aimco per common share – diluted	$ 3.15	$ 4.34	$ 2.02
Weighted average common shares/units outstanding - basic	155,882	158,890	158,793
Weighted average common shares/units outstanding - diluted	156,217	159,073	159,257
Unconsolidated Real Estate Partnerships [Member]
OPERATING EXPENSES:
Mezzanine / Unconsolidated partnerships investment income, net	$ 803	$ 77	$ 7,694
Unconsolidated Real Estate Partnerships [Member] | AIMCO Properties, LP [Member]
OPERATING EXPENSES:
Mezzanine / Unconsolidated partnerships investment income, net	803	77	7,694
Real Estate [Member]
REVENUES:
Total revenues	914,294	922,593	918,148
OPERATING EXPENSES:
Property operating expenses	311,221	307,901	319,126
Real Estate [Member] | AIMCO Properties, LP [Member]
REVENUES:
Total revenues	914,294	922,593	918,148
OPERATING EXPENSES:
Property operating expenses	311,221	307,901	319,126
Asset Management Business [Member]
REVENUES:
Total revenues	0	49,817	87,289
OPERATING EXPENSES:
Property operating expenses	0	20,921	35,458
Asset Management Business [Member] | AIMCO Properties, LP [Member]
REVENUES:
Total revenues	0	49,817	87,289
OPERATING EXPENSES:
Property operating expenses	$ 0	$ 20,921	$ 35,458

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income	$ 508,027	$ 716,603	$ 347,079
Other comprehensive (loss) gain:
Unrealized (losses) gains on available for sale debt securities	(637)	(131)	1,507
Realized and unrealized losses on interest rate swaps	0	0	(173)
Losses on interest rate swaps reclassified into earnings from accumulated other comprehensive loss	0	1,391	1,480
Other comprehensive (loss) gain	(637)	1,260	2,814
Comprehensive income	507,390	717,863	349,893
Comprehensive income attributable to noncontrolling interests	(33,906)	(50,445)	(31,527)
Comprehensive income attributable to Aimco/Operating Partnership	473,484	667,418	318,366
AIMCO Properties, LP [Member]
Net income	508,027	716,603	347,079
Other comprehensive (loss) gain:
Unrealized (losses) gains on available for sale debt securities	(637)	(131)	1,507
Realized and unrealized losses on interest rate swaps	0	0	(173)
Losses on interest rate swaps reclassified into earnings from accumulated other comprehensive loss	0	1,391	1,480
Other comprehensive (loss) gain	(637)	1,260	2,814
Comprehensive income	507,390	717,863	349,893
Comprehensive income attributable to noncontrolling interests	(187)	(8,220)	(9,185)
Comprehensive income attributable to Aimco/Operating Partnership	$ 507,203	$ 709,643	$ 340,708

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Distributions in Excess of Earnings	Total Aimco Equity	Noncontrolling Interest in Consolidated Real Estate Partnership	Common Noncontrolling Interests In Aimco Operating Partnership
Balances at Dec. 31, 2016	$ 1,944,966	$ 125,000	$ 1,521	$ 4,051,770	$ 1,011	$ (2,385,399)	$ 1,793,903	$ 151,121	$ (58)
Balances (in shares) at Dec. 31, 2016		5,000	152,143
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of Aimco Operating Partnership units	(11,882)						0	0	(11,882)
Amortization of share-based compensation cost	9,251			8,638			8,638		613
Amortization of share-based compensation cost (in shares)			17
Contributions from noncontrolling interests	3,401							3,401
Effect of changes in ownership for consolidated entities	(312,775)			(160,586)			(160,586)	(157,056)	4,867
Cumulative effect of a change in accounting principle	(65,710)					(62,682)	(62,682)		(3,028)
Change in accumulated other comprehensive income	2,814				2,592		2,592	101	121
Net income	339,315					315,774	315,774	9,084	14,457
Distributions to noncontrolling interests	(19,132)							(8,367)	(10,765)
Common Stock dividends	(226,172)					(226,172)	(226,172)
Preferred Stock dividends	(8,594)					(8,594)	(8,594)
Other, net	271		$ 3	268		0	271
Other, net (in shares)			275
Balances at Dec. 31, 2017	1,655,753	$ 125,000	$ 1,524	3,900,090	3,603	(2,367,073)	1,663,144	(1,716)	(5,675)
Balances (in shares) at Dec. 31, 2017		5,000	152,435
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchases of Common Stock	(373,593)	$ 0	$ (80)	(373,513)			(373,593)
Repurchases of Common Stock (in shares)			(7,970)
Issuance of Aimco Operating Partnership units	50,151								50,151
Redemption of Aimco Operating Partnership units	(9,639)						0	0	(9,639)
Amortization of share-based compensation cost	9,765			8,074			8,074		1,691
Amortization of share-based compensation cost (in shares)			21
Effect of changes in ownership for consolidated entities	(10,101)			(19,115)			(19,115)		9,014
Change in accumulated other comprehensive income	1,260				1,191		1,191		69
Net income	708,864					666,227	666,227	8,220	34,417
Distributions to noncontrolling interests	(22,310)							(9,471)	(12,839)
Common Stock dividends	(238,067)					(238,067)	(238,067)
Preferred Stock dividends	(8,594)					(8,594)	(8,594)
Other, net	152		$ 2	150		0	152
Other, net (in shares)			137
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)	$ 0	$ (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)	0	(5,000)
Issuance of Aimco Operating Partnership units	$ 3,034								3,034
Redemption of Aimco Operating Partnership units	(6,466)			6,242			6,244	0	(12,710)
Redemption of Aimco Operating Partnership units (in shares)			127
Redemption of Aimco Operating Partnership units			$ 2
Amortization of share-based compensation cost	9,108			5,924			5,924		3,184
Amortization of share-based compensation cost (in shares)			22
Effect of changes in ownership for consolidated entities	0			(13,243)			(13,243)	3,422	9,821
Purchase of noncontrolling interests in consolidated real estate partnerships	(3,844)							(3,844)
Change in accumulated other comprehensive income	(637)				(599)		(599)		(38)
Net income	500,514					474,083	474,083	382	26,049
Distributions to noncontrolling interests	(13,395)							(308)	(13,087)
Common Stock dividends	(241,643)					(241,643)	(241,643)
Common Stock issued to Common Stockholders in special dividend	(741)		$ 45	(786)			(741)
Common Stock issued to Common Stockholders in special dividend (in shares)			4,492
Preferred Stock dividends	(3,246)					(3,246)	(3,246)
Other, net	152		$ 1	132		0	133	19
Other, net (in shares)			82
Balances at Dec. 31, 2019	$ 1,860,795	$ 0	$ 1,489	$ 3,497,367	$ 4,195	$ (1,722,402)	$ 1,780,649	$ (3,296)	$ 83,442
Balances (in shares) at Dec. 31, 2019		0	148,885

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 508,027	$ 716,603	$ 347,079
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	380,171	377,786	366,184
Provision for real estate impairment loss	0	0	35,881
Gain on dispositions of real estate and the Asset Management business	(503,168)	(677,463)	(300,849)
Income tax benefit	(3,135)	(13,027)	(30,836)
Share-based compensation expense	8,146	8,550	7,877
Amortization of debt issuance costs and other	7,629	9,023	5,666
Other, net	25	1,065	(7,694)
Changes in operating assets and operating liabilities:
Accounts receivable and other assets	(26,021)	(27,830)	(15,841)
Accounts payable, accrued liabilities and other	2,798	1,681	(15,395)
Total adjustments	(133,555)	(320,215)	44,993
Net cash provided by operating activities	374,472	396,388	392,072
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate and deposits related to purchases of real estate	(138,311)	(242,297)	(20,372)
Capital expenditures	(393,461)	(340,489)	(358,104)
Proceeds from dispositions of real estate and the Asset Management Business	628,771	708,848	401,983
Payment for mezzanine investment and related transaction costs	(277,627)	0	0
Purchases of corporate assets	(17,584)	(7,718)	(8,899)
Proceeds from repayments on notes receivable	147	5,010	430
Other investing activities	(7,348)	(1,508)	(2,019)
Net cash (used in) provided by investing activities	(205,413)	121,846	13,019
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from non-recourse property debt	774,623	1,228,027	312,434
Principal repayments on non-recourse property debt	(520,027)	(976,087)	(409,167)
(Repayment of) proceeds from term loan	0	(250,000)	250,000
Net borrowings on revolving credit facility	114,640	93,200	49,230
Payment of debt issuance costs	(4,861)	(11,961)	(4,751)
Payment of debt extinguishment costs	(4,491)	(14,241)	(399)
Repurchases of Common Stock	(20,682)	(373,593)	0
Repurchases of Preferred Stock	(125,000)	0	0
Payment of dividends to holders of Preferred Stock	(3,246)	(8,594)	(8,594)
Payment of dividends to holders of Common Stock	(241,288)	(237,504)	(225,377)
Payment of distributions to noncontrolling interests	(21,620)	(29,196)	(26,799)
Redemptions of noncontrolling interests in the Aimco Operating Partnership	(10,694)	(9,885)	(13,546)
Contribution from noncontrolling interests in consolidated real estate partnerships	4,911	0	0
Purchases of noncontrolling interests in consolidated real estate partnerships	(3,780)	(3,579)	(314,269)
Other financing activities	(2,437)	5,233	(2,462)
Net cash used in financing activities	(63,952)	(588,180)	(393,700)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	105,107	(69,946)	11,391
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF PERIOD	72,595	142,541	131,150
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	177,702	72,595	142,541
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	160,961	199,996	196,438
Cash paid for income taxes	12,238	11,522	7,401
Non-cash transactions associated with the acquisition or disposition of real estate:
Non-recourse property debt assumed in connection with the acquisition of real estate	97,565	208,885	0
Deferred tax liability assumed in connection with the acquisition of real estate	148,809	0	0
Issuance of common OP Units in connection with acquisition of real estate	3,034	50,151	0
Non-recourse property debt assumed by buyer in connection with the disposition of the Asset Management business	0	227,708	0
Other non-cash transactions:
Recognition of right of use lease assets	54,626	0	0
Recognition of lease liabilities	59,251	0	0
Accrued capital expenditures (at end of period)	54,358	40,185	31,719
Accrued dividends on TSR restricted stock and LTIP awards (at end of period) (Note 9)	1,420	1,266	1,720
AIMCO Properties, LP [Member]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	508,027	716,603	347,079
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	380,171	377,786	366,184
Provision for real estate impairment loss	0	0	35,881
Gain on dispositions of real estate and the Asset Management business	(503,168)	(677,463)	(300,849)
Income tax benefit	(3,135)	(13,027)	(30,836)
Share-based compensation expense	8,146	8,550	7,877
Amortization of debt issuance costs and other	7,629	9,023	5,666
Other, net	25	1,065	(7,694)
Changes in operating assets and operating liabilities:
Accounts receivable and other assets	(26,021)	(27,830)	(15,841)
Accounts payable, accrued liabilities and other	2,798	1,681	(15,395)
Total adjustments	(133,555)	(320,215)	44,993
Net cash provided by operating activities	374,472	396,388	392,072
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate and deposits related to purchases of real estate	(138,311)	(242,297)	(20,372)
Capital expenditures	(393,461)	(340,489)	(358,104)
Proceeds from dispositions of real estate and the Asset Management Business	628,771	708,848	401,983
Payment for mezzanine investment and related transaction costs	(277,627)	0	0
Purchases of corporate assets	(17,584)	(7,718)	(8,899)
Proceeds from repayments on notes receivable	147	5,010	430
Other investing activities	(7,348)	(1,508)	(2,019)
Net cash (used in) provided by investing activities	(205,413)	121,846	13,019
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from non-recourse property debt	774,623	1,228,027	312,434
Principal repayments on non-recourse property debt	(520,027)	(976,087)	(409,167)
(Repayment of) proceeds from term loan	0	(250,000)	250,000
Net borrowings on revolving credit facility	114,640	93,200	49,230
Payment of debt issuance costs	(4,861)	(11,961)	(4,751)
Payment of debt extinguishment costs	(4,491)	(14,241)	(399)
Repurchases of Common Stock	(20,682)	(373,593)	0
Redemption of preferred units from Aimco	(125,000)	0	0
Payment of dividends to holders of Preferred Stock	(10,954)	(16,334)	(16,358)
Payment of distributions General Partner and Special Limited Parter	(241,288)	(237,504)	(225,377)
Payment of distributions to Limited Partners	(13,399)	(11,987)	(10,668)
Payment of distributions to noncontrolling interests	(513)	(9,469)	(8,367)
Redemption of common and preferred units	(10,694)	(9,885)	(13,546)
Contribution from noncontrolling interests in consolidated real estate partnerships	4,911	0	0
Purchases of noncontrolling interests in consolidated real estate partnerships	(3,780)	(3,579)	(314,269)
Other financing activities	(2,437)	5,233	(2,462)
Net cash used in financing activities	(63,952)	(588,180)	(393,700)
NET INCREASE (DECREASE) IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	105,107	(69,946)	11,391
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF PERIOD	72,595	142,541	131,150
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	177,702	72,595	142,541
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	160,961	199,996	196,438
Cash paid for income taxes	12,238	11,522	7,401
Non-cash transactions associated with the acquisition or disposition of real estate:
Non-recourse property debt assumed in connection with the acquisition of real estate	97,565	208,885	0
Deferred tax liability assumed in connection with the acquisition of real estate	148,809	0	0
Issuance of common OP Units in connection with acquisition of real estate	3,034	50,151	0
Non-recourse property debt assumed by buyer in connection with the disposition of the Asset Management business	0	227,708	0
Other non-cash transactions:
Recognition of right of use lease assets	54,626	0	0
Recognition of lease liabilities	59,251	0	0
Accrued capital expenditures (at end of period)	54,358	40,185	31,719
Accrued dividends on TSR restricted stock and LTIP awards (at end of period) (Note 9)	$ 1,420	$ 1,266	$ 1,720

Consolidated Statements of Part

Consolidated Statements of Partners' Capital - USD ($) $ in Thousands	Total	AIMCO Properties, LP [Member]	AIMCO Properties, LP [Member]Preferred Units [Member]	AIMCO Properties, LP [Member]General Partner and Special Limited Partner [Member]	AIMCO Properties, LP [Member]Limited Partners [Member]	AIMCO Properties, LP [Member]Partners’ Capital Attributable to the Partnership [Member]	AIMCO Properties, LP [Member]Noncontrolling Interests [Member]
Balances at Dec. 31, 2016		$ 1,944,966	$ 125,000	$ 1,668,903	$ (58)	$ 1,793,845	$ 151,121
Increase (Decrease) in Partners' Capital [Roll Forward]
Redemption of partnership units held by non-Aimco partners		(11,882)			(11,882)	(11,882)
Amortization of Aimco share-based compensation cost		9,251		8,638	613	9,251
Contributions from noncontrolling interests	$ 3,401	3,401					3,401
Effect of changes in ownership for consolidated entities		(312,775)		(160,586)	4,867	(155,719)	(157,056)
Change in accumulated other comprehensive income	2,814	2,814		2,592	121	2,713	101
Net income		339,315		315,774	14,457	330,231	9,084
Distributions to noncontrolling interests	(19,132)	(8,367)					(8,367)
Distributions to common unitholders		(236,937)		(226,172)	(10,765)	(236,937)
Distributions to preferred unitholders		(8,594)		(8,594)		(8,594)
Other, net		271		271		271
Balances at Dec. 31, 2017		1,655,753	125,000	1,538,144	(5,675)	1,657,469	(1,716)
Increase (Decrease) in Partners' Capital [Roll Forward]
Cumulative effect of a change in accounting principle		(65,710)		(62,682)	(3,028)	(65,710)
Repurchases of common partnership units		(373,593)		(373,593)		(373,593)
Issuance of Aimco Operating Partnership units	50,151	50,151			50,151	50,151
Redemption of partnership units held by non-Aimco partners		(9,639)			(9,639)	(9,639)
Amortization of Aimco share-based compensation cost		9,765		8,074	1,691	9,765
Effect of changes in ownership for consolidated entities		(10,101)		(19,115)	9,014	(10,101)
Change in accumulated other comprehensive income	1,260	1,260		1,191	69	1,260
Net income		708,864		666,227	34,417	700,644	8,220
Distributions to noncontrolling interests	(22,310)	(22,310)			(12,839)	(12,839)	(9,471)
Distributions to common unitholders		(238,067)		(238,067)		(238,067)
Distributions to preferred unitholders		(8,594)		(8,594)		(8,594)
Other, net		152		152		152
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 Stock		(125,000)	$ (125,000)			(125,000)
Issuance of Aimco Operating Partnership units	3,034	3,034			3,034	3,034
Redemption of partnership units held by non-Aimco partners		(6,466)		6,244	(12,710)	(6,466)
Amortization of Aimco share-based compensation cost		9,108		5,924	3,184	9,108
Effect of changes in ownership for consolidated entities				(13,243)	9,821	(3,422)	3,422
Purchase of noncontrolling interest in consolidated real estate partnerships		(3,844)					(3,844)
Change in accumulated other comprehensive income	(637)	(637)		(599)	(38)	(637)
Net income		500,514		474,083	26,049	500,132	382
Distributions to noncontrolling interests	$ (13,395)	(13,395)			(13,087)	(13,087)	(308)
Distributions to common unitholders		(241,643)		(241,643)		(241,643)
Distributions to preferred unitholders		(3,246)		(3,246)		(3,246)
Other, net		152		133		133	19
Common partnership units issued to common unitholders in specialdistribution		(741)		(741)		(741)
Balances at Dec. 31, 2019		$ 1,860,795		$ 1,780,649	$ 83,442	$ 1,864,091	$ (3,296)

Organization

Organization	12 Months Ended
	Dec. 31, 2019
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 December 31, 2019, after elimination of units held by consolidated subsidiaries, the Aimco Operating Partnership had 158,419,051 common OP Units outstanding. As of December 31, 2019, Aimco owned 148,885,197, or 94.0%, 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. 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 December 31, 2019, our portfolio included 124 apartment communities with 32,839 apartment homes in which we held an average ownership of approximately 99%. We consolidated 120 of these apartment communities with 32,697 apartment homes.

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	Note 2 — Basis of Presentation and Summary of Significant Accounting Policies Principles of Consolidation Aimco’s accompanying consolidated financial statements include the accounts of Aimco, the Aimco Operating Partnership and their consolidated subsidiaries. The Aimco Operating Partnership’s consolidated financial statements include the accounts of the Aimco Operating Partnership and its consolidated subsidiaries. All significant intercompany balances have been eliminated in consolidation. 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 of December 31, 2019 and 2018, Aimco consolidated six and nine VIEs, respectively, including the Aimco Operating Partnership 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. Noncontrolling Interests in the Aimco Operating Partnership Noncontrolling interests in Aimco Operating Partnership consist of common OP Units and preferred OP Units and are reflected in Aimco’s accompanying consolidated balance sheets as noncontrolling interests in Aimco Operating Partnership. Holders of preferred OP Units participate in the Aimco Operating Partnership’s income or loss only to the extent of their preferred distributions. Within Aimco’s consolidated financial statements, after provision for preferred OP Unit distributions, the Aimco Operating Partnership’s income or loss is allocated to the holders of common OP Units based on the weighted-average number of common OP Units (including those held by Aimco) outstanding during the period. During the years ended December 31, 2019, 2018, and 2017, the holders of common OP Units had a weighted-average ownership interest in the Aimco Operating Partnership of 6.0%, 4.9%, and 4.5%, respectively. Please refer to Note 8 for further information regarding the items comprising noncontrolling interests in the Aimco Operating Partnership. Substantially all of the assets and liabilities of Aimco are those of the Aimco Operating Partnership. Noncontrolling Interests in Consolidated Real Estate Partnerships We generally report the unaffiliated partners’ interests in the net assets of our consolidated real estate partnerships as noncontrolling interests in consolidated real estate partnerships within consolidated equity and partners’ capital. If a real estate partnership includes redemption rights that are not within Aimco and the Aimco Operating Partnership’s control, the noncontrolling interest is included as temporary equity or temporary capital. If the redemption right is not currently redeemable but probable of being redeemable in the future, changes in redemption value are recognized each quarter with the change in value being reflected in additional paid-in-capital. The assets of real estate partnerships consolidated by the Aimco Operating Partnership must first be used to settle the liabilities of such consolidated real estate partnerships. These consolidated real estate partnerships’ creditors do not have recourse to the general credit of the Aimco Operating Partnership. Noncontrolling interests in consolidated real estate partnerships consist primarily of equity interests held by limited partners in consolidated real estate partnerships that have finite lives. We generally attribute to noncontrolling interests their share of income or loss of consolidated partnerships based on their proportionate interest in the results of operations of the partnerships, including their share of losses even if such attribution results in a deficit noncontrolling interest balance within our equity and partners’ capital accounts. The terms of the related partnership agreements generally require the partnerships to be liquidated following the sale of the underlying real estate. As the general partner in these partnerships, we ordinarily control the execution of real estate sales and other events that could lead to the liquidation, redemption or other settlement of noncontrolling interests. Changes in our ownership interest in consolidated real estate partnerships generally consist of our purchase of an additional interest in or the sale of our entire interest in a consolidated real estate partnership. The effect on our equity and partners’ capital of our purchase of additional interests in consolidated real estate partnerships during the years ended December 31, 2019, 2018, and 2017, is shown in our consolidated statements of equity and partners’ capital. The effect on our equity and partners’ capital of sales of consolidated real estate or sales of our entire interest in consolidated real estate partnerships is reflected in our consolidated financial statements as gains or losses on dispositions of real estate and accordingly the effect on our equity and partners’ capital is reflected within the amount of net income allocated to us and to noncontrolling interests. Upon our deconsolidation of a real estate partnership following the sale of our partnership interests or liquidation of the partnership following sale of the related apartment community, we derecognize any remaining noncontrolling interest of the associated partnership previously recorded in our consolidated balance sheets. Investments in Unconsolidated Real Estate Partnerships We own general and limited partner interests in partnerships that either directly, or through interests in other real estate partnerships, own apartment communities. We generally account for investments in real estate partnerships that we do not consolidate under the equity method. Under the equity method, we recognize our share of the earnings or losses of the entity for the periods presented, inclusive of our share of any impairments and disposition gains or losses recognized by and related to such entities, and we present such amounts within income from unconsolidated real estate partnerships in our consolidated statements of operations. The excess of our cost of the acquired partnership interests over our share of the partners’ equity or deficit is generally ascribed to the fair values of land and buildings owned by the partnerships. We amortize the excess cost ascribed to the buildings over the related estimated useful lives. Such amortization is recorded as an adjustment of the amounts of earnings or losses we recognize from such unconsolidated real estate partnerships. We may also originate loans for real estate acquisitions or developments where we either expect, or have the opportunity, to participate in the residual profits from such projects. When the risks and rewards of these arrangements are similar to an equity investor or joint venture partner, we account for these arrangements as real estate investments using the equity method of accounting. We recognize as income changes in our share of net assets, adjusted for any basis differential, in mezzanine investment income, net, in our consolidated statements of operations. Real Estate Acquisitions Upon the acquisition of real estate, we determine whether the purchase qualifies as an asset acquisition or, less frequently, meets the definition of an acquisition of a business. We generally recognize the acquisition of apartment communities or interests in partnerships that own communities at our cost, including the related transaction costs, as asset acquisitions. We allocate the cost of apartment communities acquired based on the relative fair value of the assets acquired and liabilities assumed. The fair value of these assets and liabilities is determined using valuation techniques that rely on Level 2 and Level 3 inputs within the fair value framework. We determine the fair value of tangible assets, such as land, buildings, furniture, fixtures and equipment using valuation techniques that consider comparable market transactions, replacement costs and other available information. We determine the fair value of identified intangible assets or liabilities, which typically relate to in-place leases, using valuation techniques that consider the terms of the in-place leases, current market data for comparable leases and our experience in leasing similar communities. The intangible assets or liabilities related to in-place leases are comprised of: (a) the value of the above- and below-market leases in-place, measured over the period, including probable lease renewals for below-market leases, that the leases are expected to remain in effect; (b) the estimated unamortized portion of avoided leasing commissions and other costs that ordinarily would be incurred to originate the in-place leases; and (c) the value associated with leased apartment homes during an estimated absorption period, which estimates rental revenue that would not have been earned had leased apartment homes been vacant at the time of acquisition, assuming lease-up periods based on market demand and stabilized occupancy levels. The above- and below-market lease intangibles are amortized to rental revenue over the expected remaining terms of the associated leases, which include reasonably assured renewal periods. Other intangible assets related to in-place leases are amortized to depreciation and amortization over the expected remaining terms of the associated leases. Capital Additions We capitalize costs, including certain indirect costs, incurred in connection with our capital additions activities, including redevelopments, developments, other tangible apartment community improvements, and replacements of existing apartment community components. Included in these capitalized costs are payroll costs associated with time spent by employees in connection with capital additions activities at the apartment community level. We characterize as “indirect costs” an allocation of certain department costs, including payroll, at the area operations and corporate levels that clearly relate to capital additions activities. We also capitalize interest, property taxes, and insurance during periods in which construction projects are in progress. We begin capitalization of costs, including certain indirect costs, incurred in connection with our capital addition activities, upon commencement of activities necessary to ready apartment communities for their intended use. These activities include when apartment communities or apartment homes are undergoing physical construction, as well as when homes are held vacant in advance of planned construction, provided that other activities such as permitting, planning and design are in progress. We cease the capitalization of costs when the apartment communities are substantially complete and ready for their intended use, which is typically when construction has been substantially completed and apartment homes are available for occupancy. Costs, including ordinary repairs, maintenance, and resident turnover costs, are charged to property operating expense as incurred. For the years ended December 31, 2019, 2018, and 2017, we capitalized to buildings and improvements $11.8 million, $7.6 million, and $7.6 million of interest costs, respectively, and $37.8 million, $36.8 million, and $36.0 million of other direct and indirect costs, respectively. Gain or Loss on Dispositions Gain or loss on real estate dispositions are recognized when we no longer hold a controlling financial interest in the real estate and sufficient consideration has been received. Upon disposition, the related assets and liabilities are derecognized, and the gain or loss on disposition is recognized as the difference between the carrying amount of those assets and liabilities and the value of consideration received. Impairment Real estate and other long-lived assets to be held and used are stated at cost, less accumulated depreciation and amortization, unless the carrying amount of the asset is not recoverable. If events or circumstances indicate that the carrying amount of an apartment community may not be recoverable, we assess its recoverability by comparing the carrying amount to our estimate of the undiscounted future cash flows, excluding interest charges, of the community. If the carrying amount exceeds the aggregate undiscounted future cash flows, we recognize an impairment loss to the extent the carrying amount exceeds the estimated fair value of the community. As a result of our analysis, we did not recognize an impairment of our real estate and other long-lived assets to be held and used during the year ended December 31, 2019 and December 31, 2018. During the year ended December 31, 2017 we recognized an impairment related to our La Jolla Cove property, which we sold in 2018. Cash Equivalents We classify highly liquid investments with an original maturity of three months or less as cash equivalents. We maintain cash equivalents in financial institutions in excess of insured limits. We have not experienced any losses in these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions. Restricted Cash Restricted cash includes capital replacement reserves, completion repair reserves, bond sinking fund amounts, real estate tax and insurance escrow accounts held by lenders and resident security deposits. Other Assets As of December 31, 2019 and 2018, other assets was comprised of the following amounts (in thousands): 2019 2018 Investments in securitization trust that holds Aimco property debt $ 94,251 $ 83,587 Right of use lease assets 61,911 — Goodwill and other intangible assets, net 56,905 43,424 Notes receivable, net 41,300 39,254 Software, equipment and leasehold improvements 25,750 18,309 Accounts receivable, net 20,949 16,376 Prepaid expenses, real estate taxes and insurance 12,767 25,657 Investments in unconsolidated real estate partnerships 12,759 12,650 Deferred tax asset, net (Note 10) — 67,060 Deferred costs, deposits and other 24,880 45,224 Total other assets $ 351,472 $ 351,541 Investments in Securitization Trust that holds Aimco Property Debt We hold investments in a securitization trust that primarily holds certain of our property debt. These investments were initially recognized at their purchase price and the discount to the face value is being accreted into interest income over the expected term of the securities. We have designated these investments as available for sale, or AFS, debt securities and we measure these investments at fair value with changes in their fair value, other than the changes attributed to the accretion described above, recognized as an adjustment of accumulated other comprehensive income or loss within equity and partners’ capital. Please refer to Note 12 for further information regarding these debt securities. Goodwill and Other Intangible Assets, net As of December 31, 2019 Deferred Costs We defer, as debt issuance costs, lender fees and other direct costs incurred in obtaining new financing and amortize the amounts over the terms of the related loan agreements. In connection with the modification of existing financing arrangements, we defer lender fees and amortize these costs and any unamortized debt issuance costs over the term of the modified loan agreement. Debt issuance costs associated with our revolving credit facility are included in other assets in our consolidated balance sheets. Debt issuance costs associated with non-recourse property debt are presented as a direct deduction from the related liabilities in our consolidated balance sheets. When financing arrangements are repaid or otherwise extinguished prior to maturity, unamortized debt issuance costs are written off, additionally, any lender fees or other costs incurred in connection with the extinguishment are recognized as expense. Amortization and write-off of debt issuance costs and other extinguishment costs are included in interest expense in our consolidated statements of operations. We defer leasing costs incremental to a lease that we would not have incurred if the contract had not been obtained. Amortization of these costs is included in depreciation and amortization. Revenue from Leases We are a lessor primarily for residential leases. We also own approximately 1.1 million square feet of commercial space across our portfolio. In 2019 we adopted ASC 842, Leases Our operating leases with residents may also provide that the resident reimburse us for certain costs, primarily the resident’s share of utilities expenses, incurred by the apartment community. These reimbursements represent revenue attributable to nonlease components for which the timing and pattern of recognition is the same as the revenue for the lease components. We adopted the practical expedient that allows us to account for the lease and nonlease components as a single component. Reimbursement and related expense are presented on a gross basis in our consolidated statements of operations, with the reimbursement included in rental and other property revenues attributable to real estate in our consolidated statements of operations. We recognize rental revenue attributed to lease components, net of any concessions, on a straight-line basis over the term of the lease. Asset Management Business Prior to the July 2018 sale of our Asset Management business, we provided asset management and other services to certain consolidated partnerships owning apartment communities that qualify for low-income housing tax credits and are structured to provide for the pass-through of tax credits and tax deductions to their partners. We consolidated those low-income housing tax credit partnerships in which we were the sole general partner and decision maker of the partnerships. We recognized income from asset management and other services when the related fees were earned and realized or realizable. Depreciation and Amortization Depreciation for all tangible assets is calculated using the straight-line method over their estimated useful lives. Acquired buildings and improvements are depreciated over a useful life based on the age, condition, and other physical characteristics of the asset. Furniture, fixtures, and equipment are generally depreciated over five years. We depreciate capitalized costs using the straight-line method over the estimated useful life of the related improvement, which is generally 5, 15, or 30 years. We also capitalize payroll and other indirect costs incurred in connection with preparing an asset for its intended used. These costs include corporate-level costs that clearly relate to the capital addition activities, which we allocate to the applicable assets. All capitalized payroll costs and indirect costs are allocated to capital additions proportionately based on direct costs and depreciated over the estimated useful lives of such capital additions. Purchased software and other costs related to software purchased or developed for internal use are capitalized during the application development stage and are amortized using the straight-line method over the estimated useful life of the software, generally three to five years. Purchased equipment is recognized at cost and depreciated using the straight-line method over the estimated useful life of the asset, which is generally five years. Leasehold improvements are also recorded at cost and depreciated on a straight-line basis over the shorter of the asset’s estimated useful life or the term of the related lease. Certain homogeneous items that are purchased in bulk on a recurring basis, such as appliances, are depreciated using group methods that reflect the average estimated useful life of the items in each group. Except in the case of apartment community casualties, where the net book value of the lost asset is written off in the determination of casualty gains or losses, we generally do not recognize any loss in connection with the replacement of an existing apartment community component because normal replacements are considered in determining the estimated useful lives used in connection with our composite and group depreciation methods. Insurance We believe our insurance coverages insure our apartment communities adequately against the risk of loss attributable to fire, earthquake, hurricane, tornado, flood, and other perils. In addition, we have third-party insurance coverage (after self-insured retentions) that defray the costs of large workers’ compensation, health, and general liability exposures. We accrue losses based upon our estimates of the aggregate liability for uninsured losses incurred using certain actuarial assumptions followed in the insurance industry and based on our experience. Share-Based Compensation We issue various forms of share-based compensation, including stock options and restricted stock awards with service conditions and/or market conditions. We recognize share-based employee compensation based on the fair value on the grant date and recognize compensation cost over the awards’ requisite service periods. We reduce compensation cost related to forfeited awards in the period of forfeiture. Please refer to Note 9 for further discussion of our share-based compensation. Income Taxes Aimco has elected to be taxed as a REIT under the Internal Revenue Code commencing with its taxable year ended December 31, 1994, and it intends to continue to operate in such a manner. Aimco’s current and continuing qualification as a REIT depends on its ability to meet the various requirements imposed by the Internal Revenue Code, which are related to organizational structure, distribution levels, diversity of stock ownership and certain restrictions with regard to owned assets and categories of income. If Aimco qualifies for taxation as a REIT, it will generally not be subject to United States federal corporate income tax on its taxable income that is currently distributed to stockholders. This treatment substantially eliminates the “double taxation” (at the corporate and stockholder levels) that generally results from an investment in a corporation. Even if Aimco qualifies as a REIT, it may be subject to United States federal income and excise taxes in various situations, such as on undistributed income. Aimco also will be required to pay a 100% tax on any net income on non-arm’s length transactions between it and a TRS (described below) and on any net income from sales of apartment communities that were held for sale in the ordinary course. The state and local tax laws may not conform to the United States federal income tax treatment, and Aimco may be subject to state or local taxation in various state or local jurisdictions, including those in which we transact business. Any taxes imposed on us reduce our operating cash flow and net income. Certain of our operations or a portion thereof, including property management and risk management, are conducted through taxable REIT subsidiaries, which are subsidiaries of the Aimco Operating Partnership, and each of which we refer to as a TRS. A TRS is a subsidiary C-corporation that has not elected REIT status and , as such , is subject to United States federal corporate income tax. We use TRS entities to facilitate our ability to offer certain services and activities to our residents and investment partners that cannot be offered directly by a REIT. We also use TRS entities to hold investments in certain apartment communities. For our TRS entities, deferred income taxes result from temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for United States federal income tax purposes, and are measured using the enacted tax rates and laws that are expected to be in effect when the differences reverse. We reduce deferred tax assets by recording a valuation allowance when we determine, based on available evidence, that it is more likely than not that the assets will not be realized. We recognize the tax consequences associated with intercompany transfers between the Aimco Operating Partnership and TRS entities when such transactions occur. Please refer to Note 10 for further information about our income taxes. Earnings per Share and Unit Aimco and the Aimco Operating Partnership calculate earnings per share and unit based on the weighted-average number of shares of Common Stock or common partnership units, participating securities, common stock or common unit equivalents and dilutive convertible securities outstanding during the period. The Aimco Operating Partnership considers both common partnership units and equivalents, which have identical rights to distributions and undistributed earnings, to be common units for purposes of the earnings per unit computations. Please refer to Note 11 for further information regarding earnings per share and unit computations. Use of Estimates The preparation of our 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 On February 20, 2019, Aimco and the Aimco Operating Partnership effected a reverse split of Common Stock and common partnership units, respectively, at a ratio of one share or unit for every 1.03119 shares or units outstanding on the date of effectiveness. The accounting guidance for recapitalization events requires that we revise Aimco’s equity and the Aimco Operating Partnership’s partners’ capital as if the reverse split had occurred at the beginning of the earliest period presented. As such, we have revised the outstanding share and unit counts, presentation of share and unit activity, and earnings per share and unit, as if the reverse split had occurred on December 31, 2016. Accounting Pronouncements Adopted in the Current Year Effective January 1, 2019, we adopted ASC 842 issued by the Financial Accounting Standards Board, or FASB. We elected to adopt the new standard using practical expedients that do not require a look back to expired or existing contracts for embedded leases, allow us to retain the classification of existing leases, and allow us to retain the previous accounting for the initial direct costs of existing leases. As both a lessee and a lessor, we also elected to use the practical expedient that allows us to combine revenue attributable to nonlease components with associated lease components where the timing and pattern of transfer of the components are the same. Under the new standard, a contract is or contains a lease when it provides the right to control the use of an asset for a period of time in exchange for consideration. Lessor accounting remains largely unchanged other than how we recognize costs incurred to obtain leases. Under ASC 842, we defer leasing costs incremental to a lease that we would not have incurred if the contract had not been obtained. As a result of the practical expedient related to the combination of revenue from nonlease and lease components described above, we will combine rent payments with payments for other services we provide to our residents, including residents’ reimbursement of utility expenses. We have adopted the standard using the optional transition method that allows for prior reporting periods to remain as originally presented. Please refer to Note 4. In 2018, the Securities Exchange Commission, or SEC, amended its rules to eliminate, modify, or integrate into other SEC requirements certain disclosure rules. The amendments are intended to simplify compliance without significantly changing the total mix of information provided to investors. The amendments created a requirement to report dividends per share or unit and changes in equity in interim periods on a comparative basis for both quarter-to-date and year-to-date periods presented. Recent Accounting Pronouncements In 2016, the FASB issued ASC 326, Financial Instruments-Credit Losses financial instrument, including receivables, at its inception. Our notes receivable and AFS debt securities are subject to the new standard. For AFS debt securities, the new standard would require us to estimate a credit loss if the fair value of the instruments are less than their carrying value of the instruments . This credit loss standard is required to be applied using a modified-retrospective approach and requires a cumulative-effect adjustment to retained earnings be recorded as of the date of adoption. We adopted the new standard on January 1, 2020. The adoption of the standard is not expected to have a material impact on our financial position or results of operations.

Significant Transactions

Significant Transactions	12 Months Ended
	Dec. 31, 2019
Significant Transactions [Abstract]
Significant Transactions	Note 3 — Significant Transactions Parkmerced Mezzanine Investment On November 26, 2019, we loaned $275 million to the partnership that owns Parkmerced Apartments. The loan accrues interest at 10% per annum with a five-year five-year ten-year Receivables Acquisitions During the year ended December 31, 2019, we acquired a 95% interest in 1001 Brickell Bay Drive, a 1.8-acre waterfront parcel in Miami, Florida, currently improved with an office building. The remaining 5% is held by an outside partner and is redeemable at the holder’s option for cash during a three-month We also acquired One Ardmore, an apartment community located in Ardmore, Pennsylvania, a suburb of Philadelphia, and Prism, an apartment community under development in Cambridge, Massachusetts. Summarized information regarding these acquisitions is set forth in the table below (in thousands): Purchase price $ 229,711 Capitalized transaction costs 4,057 Noncontrolling interests in consolidated real estate partnership 8,250 Total consideration (1) $ 242,018 Consideration allocated to building and improvements 218,752 Consideration allocated to land 162,094 Consideration allocated to intangible assets 16,500 Consideration allocated to intangible liabilities (6,519 ) Deferred tax liability assumed (2) (148,809 ) Total consideration $ 242,018 (1) Total consideration includes $97.6 million of debt assumed and issuance of 59,761 common OP Units. In accordance with GAAP, the common OP Units were valued at $50.77 per unit, the Aimco Common Stock closing price on the purchase date. (2) The deferred tax liability of $148.8 million resulted from the corporate structure used to complete the acquisition of 1001 Brickell Bay Drive and is due to the difference between the purchase price determined in accordance with GAAP and the tax basis of the property. Dispositions of Apartment Communities During the years ended December 31, 2019, 2018, and 2017, we sold apartment communities as summarized below (dollars in thousands): 2019 2018 2017 Number of apartment communities sold 12 4 5 Number of apartment homes sold 3,596 1,334 2,291 Gain on dispositions of real estate (1) $ 503,168 $ 175,213 $ 297,730 (1) During the year ended December 31, 2019, gain on dispositions of real estate includes the expiration of indemnification liabilities related to the sale of our Asset Management business. The apartment communities sold were predominantly located outside of our primary markets or in lower-rated locations within our primary markets and had average revenues per apartment home significantly below those of our retained portfolio . During the year ended December 31, 2018, we also sold for $590.0 million our Asset Management business and our four affordable apartment communities located in the Hunters Point area of San Francisco. The sale resulted in a gain of $500.3 million and net cash proceeds of $512.2 million, after payment of transaction costs and repayment of property-level debt. Additionally, we sold our interest in the entities owning the La Jolla Cove property. We provided seller financing with a stated value of $48.6 million and received net cash proceeds of approximately $5.0 million. In addition to the apartment communities we sold during the current period, from time to time we may be marketing for sale certain 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 December 31, 2019, no communities were classified as held for sale.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	Note 4 — Leases Lessor Arrangements The majority of payments we receive for our residential and commercial leases are fixed. We receive variable payments from our residents and commercial tenants primarily for utility reimbursements. Our total lease income was comprised of the following amounts for all operating leases for the year ended December 31, 2019 (in thousands): Fixed lease income $ 855,326 Variable lease income 56,424 Total lease income $ 911,750 In general, our commercial leases have options to extend for a certain period of time at the tenant’s option. Future minimum annual rental payments we will receive under commercial leases, excluding such extension options, are as follows as of December 31, 2019 (in thousands): 2020 $ 26,770 2021 23,277 2022 19,766 2023 15,853 2024 13,512 Thereafter 52,040 Total $ 151,218 Generally, our residential leases do not provide extension options and, as of December 31, 2019, have an average remaining term of 8.8 months. Lessee Arrangements Beginning in 2019, we recognize right of use assets and related lease liabilities, which are included in other assets and accrued liabilities and other, respectively, in our consolidated balance sheets. We estimated the value of the lease liabilities using a discount rate equivalent to the rate we would pay on a secured borrowing with similar terms to the lease. On October 1, 2019, we revised our estimate of the incremental borrowing rate, which resulted in a reduction of our right of use assets and related lease liabilities for ground leases. The adjustment recorded to our right of use assets and lease liabilities did not impact our consolidated statements of operations. Substantially all of the payments under our ground and office leases are fixed. We exclude o ptions to extend the lease in our minimum lease terms unless the option is reasonably certain to be exercised. Our total lease cost for ground and office leases f As of December 31, 2019, the ground and office leases have weighted-average remaining terms of 74.0 years and 8.4 years, respectively, and weighted-average discount rates of 6.55% and 3.22%, respectively. Minimum annual rental payments under these operating leases, reconciled to the lease liability included in accrued liabilities and other in our consolidated balance sheets, are as follows (in thousands): Operating Lease Future Minimum Rent 2020 $ 5,156 2021 5,143 2022 5,053 2023 4,363 2024 4,392 Thereafter 427,935 Total $ 452,042 Less: Discount (394,735 ) Total lease liability $ 57,307

Non-Recourse Property Debt and

Non-Recourse Property Debt and Credit Agreement	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Non-Recourse Property Debt and Credit Agreement	Note 5 — Non-Recourse Property Debt and Credit Agreement Non-Recourse Property Debt We finance apartment communities in our portfolio primarily using property-level, non-recourse, long-dated, fixed-rate, amortizing debt. The following table summarizes non-recourse property debt related to assets classified as held for use as of December 31, 2019 and 2018 (dollars in thousands): Latest Maturity Date Interest Rate Range Weighted-Average Interest Rate 2019 2018 Fixed-rate property debt January 1, 2055 2.73% to 6.79% 3.93% $ 4,081,221 $ 3,676,882 Variable-rate property debt July 13, 2033 2.51% to 3.00% 2.88% 170,118 260,118 Debt issuance costs, net of accumulated amortization (20,749) (21,695 ) Non-recourse property debt, net $ 4,230,590 $ 3,915,305 Principal and interest on fixed-rate debt are generally payable monthly or in monthly interest-only payments with balloon payments due at maturity. As of December 31, 2019, our fixed-rate property debt was secured by 78 apartment communities that had an aggregate net book value of $4.3 billion. Principal and interest on variable-rate debt are generally payable in semi-annual installments with balloon payments due at maturity. As of December 31, 2019, our variable-rate property debt was secured by seven apartment communities that had an aggregate net book value of $105.7 million. These non-recourse property debt instruments contain covenants common to the type of borrowing, and as of December 31, 2019, we were in compliance with all such covenants. As of December 31, 2019, the scheduled principal amortization and maturity payments for the non-recourse property debt were as follows (in thousands): Amortization Maturities Total 2020 $ 92,177 $ 78,930 $ 171,107 2021 (1) 83,427 598,263 681,690 2022 78,909 260,671 339,580 2023 71,332 249,251 320,583 2024 67,561 285,517 353,078 Thereafter 391,512 1,993,789 2,385,301 Total $ 784,918 $ 3,466,421 $ 4,251,339 (1) Pursuant to the terms of our loan agreements, we may prepay in 2020 $246.5 million of loans maturing in 2021, without penalty. Revolving Credit Facility We have a revolving credit facility with a syndicate of financial institutions. Our revolving credit facility provides for $800.0 million of revolving loan commitments. As of December 31, 2019 and 2018, we had $275.0 million and $160.4 million, respectively, of outstanding borrowings under our revolving credit facility. The interest rate on our outstanding borrowings was 3.00% and 3.93% as of December 31, 2019 and 2018, respectively. As of December 31, 2019, after outstanding borrowings and $7.2 million of undrawn letters of credit backed by the Credit Agreement, our available borrowing capacity was $517.8 million. Borrowings against the revolving loan commitments bear interest at a rate set forth on a pricing grid, which rate varies based on our credit rating as assigned by specified rating agencies (LIBOR plus 1.20%, or, at our option, a base rate plus 0.20% as of December 31, 2019). The revolving credit facility matures on January 22, 2022. The revolving credit facility provides that we may make distributions to our investors during any four consecutive quarters in an aggregate amount that does not exceed the greater of 95% of our funds from operations, as defined by Nareit, for such period, subject to certain non-cash adjustments, or such amount as may be necessary to maintain Aimco’s REIT status.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 6 — Commitments and Contingencies Commitments In connection with our redevelopment, development, and other capital improvement 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 December 31, 2019, our commitments related to active redevelopments and developments totaled approximately $254.5 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. We also have a contingent liability related to a property in Lake Tahoe, California, regarding environmental contamination from the historic operation of a dry cleaner. An entity owned by us was the former general partner of a now-dissolved partnership that previously owned a site that was a laundromat with a self-service dry-cleaning machine. 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 are appealing the final order while simultaneously complying with it. Although the outcome of this process is uncertain, we do not expect its resolution to have a material adverse effect on our consolidated financial condition, results of operations or cash flows. We have determined that our legal obligations to remove or remediate certain potentially hazardous materials may be conditional asset retirement obligations, as defined 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 December 31, 2019, are immaterial to our consolidated financial condition, results of operations and cash flows.

Aimco Equity

Aimco Equity	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Aimco Equity	Note 7 — Aimco Equity Preferred Stock During the year ended December 31, 2019, Aimco redeemed all of the outstanding shares of its 6.88% Class A Cumulative Preferred Stock. Aimco’s Class A Preferred Stock had a $0.01 per share par value, was senior to Aimco’s Common Stock, had a liquidation preference per share of $25.00. In connection with the redemption of Aimco preferred stock, the Aimco Operating Partnership redeemed from Aimco a number of Preferred Partnership Units equal to the number of shares redeemed by Aimco. Common Stock During the years ended December 31, 2019, 2018, and 2017, Aimco declared dividends per common share of $1.56, $1.52 and $1.44, respectively. On February 3, 2019, Aimco’s Board of Directors authorized a reverse stock split, in which every 1.03119 Aimco common share was combined into one Aimco common share, effective at the close of business on February 20, 2019. On the same date, the Board of Directors also declared a special dividend on the Aimco Common Stock that consisted of $67.1 million in cash, 4.5 Stockholders had the opportunity to elect to receive the special dividend in the form of all cash or all stock, subject to proration if either option was oversubscribed. Aimco’s Board of Directors also authorized a reverse stock split intended to neutralize the dilutive impact of the stock issued in the special dividend. As a result, the total number of shares outstanding after the stock dividend and reverse split was unchanged from the number of shares outstanding immediately prior to the two actions. All equity and earnings per share data, including the number of shares outstanding, have been retroactively adjusted to reflect the reverse stock split for all periods presented in this Annual Report on Form 10-K. Change to our charter On February 24, 2020, pursuant to Maryland law and our charter, our Board of Directors reclassified into Common Stock, all of the authorized and unissued shares of each of the following classes of preferred stock: Class Z Cumulative Preferred Stock, Class A Cumulative Preferred Stock, and Series A Community Reinvestment Act Preferred Stock. The reclassification increases the number of authorized shares classified as Common Stock by 9,800,240 shares, from 500,787,260 shares immediately prior to the reclassification to 510,587,500 shares immediately after the reclassification. The reclassification does not impact any of our issued and outstanding shares of preferred stock. Registration Statements Aimco and the Aimco Operating Partnership have a shelf registration statement that provides for the issuance of equity and debt securities by Aimco and debt securities by the Aimco Operating Partnership.

Partners' Capital

Partners' Capital	12 Months Ended
	Dec. 31, 2019
Partners Capital [Abstract]
Partners' Capital	Note 8 —Partners’ Capital Redeemable Preferred OP Units The Aimco Operating Partnership has outstanding various classes of redeemable preferred OP Units. As of December 31, 2019 and 2018, the Aimco Operating Partnership had the following classes of preferred OP Units (stated at their redemption values, in thousands, except unit and per unit data): Distributions per Annum Units Issued and Outstanding Redemption Values Class of Preferred Units Percent Per Unit 2019 2018 2019 2018 Class One 8.75 % $ 8.00 90,000 90,000 $ 8,229 $ 8,229 Class Two 1.92 % $ 0.48 11,122 14,240 278 356 Class Three 7.88 % $ 1.97 1,338,524 1,338,524 33,463 33,463 Class Four 8.00 % $ 2.00 644,954 644,954 16,124 16,124 Class Six 8.50 % $ 2.13 773,693 773,693 19,342 19,342 Class Seven 7.87 % $ 1.97 26,150 27,960 654 699 Class Nine 6.00 % $ 1.50 78,956 243,112 1,974 6,078 Class Ten 6.00 % $ 1.50 680,000 680,000 17,000 17,000 Total 3,643,399 3,812,483 $ 97,064 $ 101,291 Each class of preferred OP Units is currently redeemable at the holders’ option. The Aimco Operating Partnership, at its sole discretion, may settle such redemption requests in cash or cause Aimco to issue shares of its Common Stock with a value equal to the redemption price. In the event the Aimco Operating Partnership requires Aimco to issue shares of Common Stock to settle a redemption request, the Aimco Operating Partnership would issue to Aimco a corresponding number of common OP Units. The Aimco Operating Partnership has a redemption policy that requires cash settlement of redemption requests for the preferred OP Units, subject to limited exceptions. Subject to certain conditions, the Class Four and Class Six preferred OP Units may be converted into common OP Units. These redeemable units are classified within temporary equity in Aimco’s consolidated balance sheets and within temporary capital in the Aimco Operating Partnership’s consolidated balance sheets. During the years ended December 31, 2019, 2018, and 2017, approximately 169,000, 10,000 and 67,000 preferred OP Units, respectively, were redeemed in exchange for cash, and no preferred OP Units were redeemed in exchange for shares of Aimco Common Stock or common OP Units. The following table presents a reconciliation of the Aimco Operating Partnership’s preferred OP Units during the year ended December 31, 2019 (in thousands): 2019 Balance at January 1 $ 101,291 Preferred distributions (7,708 ) Redemption of preferred units (4,227 ) Net income 7,708 Balance at December 31 $ 97,064 Aimco Operating Partnership Partners’ Capital Common Partnership Units In the Aimco Operating Partnership’s consolidated balance sheets, the common partnership units held by Aimco are classified within Partners’ Capital as General Partner and Special Limited Partner capital and the common OP Units are classified within Limited Partners’ capital. In Aimco’s consolidated balance sheets, the common OP Units are classified within permanent equity as common noncontrolling interests in the Aimco Operating Partnership. Common partnership units held by Aimco are not redeemable whereas common OP Units are redeemable at the holders’ option, subject to certain restrictions, on the basis of one common OP Unit for either one share of Common Stock or cash equal to the fair value of a share of Common Stock at the time of redemption. Aimco has the option to deliver shares of Common Stock in exchange for all or any portion of the common OP Units tendered for redemption. When a limited partner redeems a common OP Unit for Common Stock, Limited Partners’ capital is reduced and the General Partner and Special Limited Partners’ capital is increased. During the years ended December 31, 2019, 2018, and 2017, approximately 129,000, 224,000 and 268,000 common OP Units, respectively, were redeemed in exchange for cash. During the year ended December 31, 2019, 127,000 common OP Units were redeemed in exchange for shares of Common Stock. common OP U nits were redeemed in exchange for Aimco Common Stock during the years ended December 31, 2018 and 201 7 . The holders of the common OP Units receive distributions, prorated from the date of issuance, in an amount equivalent to the dividends paid to holders of Common Stock. During the years ended December 31, 2019, 2018, and 2017, the Aimco Operating Partnership declared distributions per common unit of $1.56, $1.52 and $1.44, respectively. On February 3, 2019, the Board of Directors of the Aimco Operating Partnership’s general partner authorized a reverse unit split and special distribution in the same form and with the same timing as the reverse stock split and special dividend discussed in Note 7 above. The special distribution to the holders of Aimco Operating Partnership common partnership units that consisted of $72.7 million in cash, 4.8 million common partnership units and $0.4 million of cash paid in lieu of issuing fractional units. Total common partnership units outstanding prior to and following both transactions was unchanged.

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	Note 9 — Share-Based Compensation We have a stock award and incentive program to attract and retain officers and independent directors. As of December 31, 2019, approximately 3.9 million shares were available for issuance under our Amended and Restated 2015 Stock Award and Incentive Plan, or the 2015 Plan. The total number of shares available for issuance under this plan may increase due to any forfeiture, cancellation, exchange, surrender, termination or expiration of an award outstanding under our 2007 Stock Award and Incentive Plan. Awards under the 2015 Plan may be in the form of incentive stock options, non-qualified stock options and restricted stock, or other types of awards as authorized under the plan. Our plans are administered by the Compensation and Human Resources Committee of Aimco’s Board of Directors. In the case of stock options, the exercise price of the options granted may not be less than the fair market value of a share of Common Stock at the date of grant. Total compensation cost recognized for share-based awards was as follows for the years ended December 31, 2019, 2018, and 2017 (in thousands): 2019 2018 2017 Share-based compensation expense (1) $ 8,146 $ 8,550 $ 7,877 Capitalized share-based compensation (2) 962 1,215 1,374 Total share-based compensation (3) $ 9,108 $ 9,765 $ 9,251 (1) Amounts are recorded in general and administrative expenses on the consolidated statements of operations. (2) Amounts are recorded in building and improvements on the consolidated balance sheets. (3) Amounts are recorded in additional paid-in capital and common noncontrolling interests in the Aimco Operating Partnership on the Aimco consolidated balance sheets, and in general partner and special limited partner and limited partners on the Aimco Operating Partnership consolidated balance sheets. As of December 31, 2019, total unvested compensation cost not yet recognized was $10.3 million. We expect to recognize this compensation over a weighted-average period of approximately 1.6 years. We grant stock options and restricted stock awards that are subject to time-based vesting and require continuous employment, typically over a period of four years from the grant date, and we refer to these awards as Time-Based Stock Options and Time-Based Restricted Stock, respectively. We also grant stock options, restricted stock awards, and two forms of long-term incentive partnership units, or LTIP units, that vest conditioned on Aimco’s total shareholder return, or TSR, relative to the NAREIT Equity Apartment Index (60% weighting) and the MSCI US REIT Index (40% weighting) over a forward-looking performance period of three years. We refer to these awards as TSR Stock Options, TSR Restricted Stock, TSR LTIP I units, and TSR LTIP II units. Vested LTIP II units may be converted at the holders’ option to LTIP Units for a strike price over a term of 10 years. Earned TSR-based awards, if any, will vest 50% on each of the third anniversary and fourth anniversary of the grant date, based on continued employment. Our Time-Based Stock Options and TSR Stock Options expire generally 10 years from the date of grant. We recognize compensation cost associated with Time-Based awards ratably over the requisite service periods, which are typically four years. We recognize compensation cost related to the TSR-based awards, which have graded vesting periods, over the requisite service period for each separate vesting tranche of the award, commencing on the grant date. The value of the TSR-based awards take into consideration the probability that the market condition will be achieved; therefore previously recorded compensation cost is not adjusted in the event that the market condition is not achieved and awards do not vest. We had Time-Based Stock Options, Time-Based Restricted Stock, TSR Stock Options, TSR Restricted Stock, TSR LTIP I units and TSR LTIP II units outstanding as of December 31, 2019. Stock Options The following table summarizes activity for our outstanding stock options, for the years ended December 31, 2019, 2018, and 2017 (options in thousands): 2019 2018 2017 Number of Options Weighted-Average Exercise Price Number of Options Weighted-Average Exercise Price Number of Options Weighted-Average Exercise Price Outstanding at beginning of year 646 $ 40.12 648 $ 40.08 675 $ 29.55 Granted — — — — 184 44.07 Exercised (5 ) 8.92 (2 ) 28.33 (211 ) 9.90 Forfeited — — — — — — Outstanding at end of year 641 $ 40.30 646 $ 40.12 648 $ 40.08 Exercisable at end of year 458 $ 38.78 186 $ 38.18 128 $ 37.59 The intrinsic value of a stock option represents the amount by which the current price of the underlying stock exceeds the exercise price of the option. As of December 31, 2019, stock options outstanding had an aggregate intrinsic value of $7.3 million and a weighted-average remaining contractual term of 6 years. Stock options exercisable as of December 31, 2019, had an aggregate intrinsic value of $5.9 million and a weighted-average remaining contractual term of 5.5 years. The intrinsic value of stock options exercised during the years ended December 31, 2019, 2018, and 2017, was $0.1 million, $0.0 million and $7.1 million, respectively. During 2017, we granted TSR Stock Options. The weighted-average grant date fair value of stock options granted during the year ended 2017 was $11.39 per option. Time-Based Restricted Stock Awards The following table summarizes activity for Time-Based Restricted Stock awards for the years ended December 31, 2019, 2018, and 2017 (shares in thousands): 2019 2018 2017 Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Unvested at beginning of year 121 $ 40.82 155 $ 37.63 241 $ 33.61 Granted 48 47.71 49 40.01 44 44.07 Vested (75 ) 42.76 (83 ) 34.42 (130 ) 32.35 Forfeited (2 ) 38.80 — — — — Unvested at end of year 92 $ 42.86 121 $ 40.82 155 $ 37.63 The aggregate fair value of Time-Based Restricted Stock awards and TSR Restricted Stock awards that vested during the years ended December 31, 2019, 2018, and 2017 was $13.7 million, $8.4 million and $6.0 million, respectively. TSR Restricted Stock Awards The following table summarizes activity for TSR Restricted Stock awards for the years ended December 31, 2019, 2018, and 2017 (shares in thousands): 2019 2018 2017 Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Unvested at beginning of year 171 $ 41.65 246 $ 40.70 208 $ 39.66 Granted (1) 39 54.73 44 41.71 38 46.39 Change in awards (2) 216 39.67 — — — — Vested (213 ) 39.67 (119 ) 39.72 — — Unvested at end of year 213 $ 43.99 171 $ 41.65 246 $ 40.70 (1) Based on target performance payout. (2) Represents the change in the number of restricted stock awards earned at the end of the measurement period. TSR LTIP I Units The following table summarizes activity for TSR LTIP I units for the years ended December 31, 2019, 2018, and 2017 (units in thousands): 2019 2018 2017 Number of Units Weighted-Average Grant-Date Fair Value Number of Units Weighted-Average Grant-Date Fair Value Number of Units Weighted-Average Grant-Date Fair Value Unvested at beginning of year 93 $ 43.78 45 $ 46.21 — $ — Granted 6 55.17 48 41.48 45 46.21 Unvested at end of year 99 $ 44.38 93 $ 43.78 45 $ 46.21 TSR LTIP II Units The following table summarizes activity for TSR LTIP II units for the years ended December 31, 2019 and 2018 (units in thousands): 2019 2018 Number of Units Weighted-Average Grant-Date Fair Value Number of Units Weighted-Average Grant-Date Fair Value Unvested at beginning of year 243 $ 8.29 — $ — Granted 356 12.03 243 8.29 Unvested at end of year 599 $ 10.51 243 $ 8.29 Determination of Grant-Date Fair Value of Awards We estimated the fair value of TSR-based awards granted in 2019, 2018, and 2017 using a Monte Carlo model with the assumptions set forth in the table below. The risk-free interest rate reflects the annualized yield of a zero coupon United States Treasury security with a term equal to the expected term of the awards. The expected dividend yield reflects expectations regarding cash dividend amounts per share paid on Aimco’s Common Stock during the expected term of the awards. Expected volatility reflects an average of the historical volatility of Aimco’s Common Stock during the historical period commensurate with the expected term of the award that ended on the date of grant, and the implied volatility is calculated from observed call option contracts closest to the expected term. The derived vesting period of TSR Restricted Stock and TSR LTIP I units was determined based on the graded vesting terms. The expected term of the TSR-options and TSR LTIP II units was based on historical exercises and post-vesting terminations. The valuation assumptions for the 2019, 2018, and 2017 grants were as follows: 2019 2018 2017 Grant date market value of a common share $ 49.24 $ 40.95 $ 44.07 Risk-free interest rate 2.59% - 2.66 % 2.32% - 2.68 % 1.57% - 2.22 % Dividend yield 3.09 % 3.52 % 3.27 % Expected volatility 19.08% - 19.24 % 17.64% - 18.02 % 21.33% - 23.00 % Derived vesting period of TSR Restricted Stock and TSR LTIP I units 3.4 years 3.4 years 3.4 years Weighted average expected term of TSR Stock Options and LTIP II units 5.8 years 5.6 years 5.8 years The grant date fair value for the Time-Based Restricted Stock awards reflects the closing price of a share of Aimco Common Stock on the grant date.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 10 — Income Taxes Deferred income taxes reflect the net effects of temporary differences between the carrying amounts of assets and liabilities of the TRS entities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax liabilities and assets are as follows (in thousands): December 31, 2019 2018 Deferred tax liabilities: Real estate and real estate partnership basis differences $ 126,269 $ 12,058 Deferred tax assets: Tax credit carryforwards $ 53,776 $ 67,530 Net operating, capital and other loss carryforwards 6,147 7,022 Accruals and expenses 6,138 7,432 Management contracts and other 1,379 2,064 Total deferred tax assets 67,440 84,048 Valuation allowance (4,766 ) (4,930 ) Net deferred tax (liabilities) assets $ (63,595 ) $ 67,060 As of December 31, 2019, deferred tax liabilities, net, were presented in accrued liabilities and other in our consolidated balance sheets. As of December 31, 2018, deferred tax assets, net, were presented in other assets in our consolidated balance sheets. During the year ended December 31, 2019, we recognized a $148.8 million deferred tax liability in connection with the acquisition of 1001 Brickell Bay Drive, as discussed in Note 3. As of December 31, 2019, we had federal and state net operating loss carryforwards, or NOLs, for which the deferred tax asset was approximately $6.1 million, before a valuation allowance of $4.8 million. The NOLs expire in years 2020 to 2038. Subject to certain separate return limitations, we may use these NOLs to offset a portion of state taxable income generated by our TRS entities. As of December 31, 2019, we also had low-income housing and rehabilitation tax credit carryforwards and corresponding deferred tax assets of approximately $53.8 million for income tax purposes that expire in years 2035 to 2039. A reconciliation of the beginning and ending balance of our unrecognized tax benefits is presented below (in thousands): 2019 2018 2017 Balance at January 1 $ 2,618 $ 2,476 $ 2,286 Additions based on tax position taken in current year 2,758 — — Additions based on tax positions related to prior years 226 142 190 Reductions as a result of a lapse of the applicable statutes (522 ) — — Balance at December 31 $ 5,080 $ 2,618 $ 2,476 Because the statute of limitations has not yet elapsed, our United States federal income tax returns for the year ended December 31, 2014, and subsequent years and certain of our State income tax returns for the year ended December 31, 2014, and subsequent years are currently subject to examination by the IRS or other taxing authorities. If recognized, the unrecognized benefit would affect the effective rate. In 2014, the IRS initiated an audit of the Aimco Operating Partnership’s 2011 and 2012 tax years. This audit was concluded during the year ended December 31, 2019, with no material effect on our tax benefits, financial condition or results of operations. Our policy is to include any interest and penalties related to income taxes within the income tax line item in our consolidated statements of operations. In accordance with the accounting requirements for stock-based compensation, we may recognize tax benefits in connection with the exercise of stock options by employees of our TRS entities and the vesting of restricted stock awards. We recognize the tax effects related to stock-based compensation through earnings in the period the compensation was recognized. Significant components of the income tax benefit or expense are as follows and are classified within income tax benefit in our consolidated statements of operations for the years ended December 31, 2019, 2018, and 2017 (in thousands): 2019 2018 2017 Current: Federal $ 6,115 $ 11,269 $ (938 ) State 8,982 10,537 525 Total current 15,097 21,806 (413 ) Deferred: Federal (12,891 ) (29,243 ) (10,908 ) State (5,341 ) (5,590 ) (3,621 ) Revaluation of deferred taxes due to change in tax rate — — (15,894 ) Total deferred (18,232 ) (34,833 ) (30,423 ) Total benefit $ (3,135 ) $ (13,027 ) $ (30,836 ) Consolidated income or loss subject to tax consists of pretax income or loss of our TRS entities and income and gains retained by the REIT. For the years ended December 31, 2019, 2018, and 2017, we had consolidated net loss subject to tax of $21.2 million, net income subject to tax of $158.6 million, and net loss subject to tax of $55.6 million, respectively. Net loss subject to tax for the year ended December 31, 2019 included a $7.7 million net loss of a foreign subsidiary. The reconciliation of income tax attributable to operations computed at the United States statutory rate to income tax benefit is shown below (dollars in thousands): 2019 2018 2017 Amount Percent Amount Percent Amount Percent Tax (benefit) provision at United States statutory rates on consolidated income or loss subject to tax $ (4,442 ) 21.0 % $ 33,296 21.0 % $ (19,459 ) 35.0 % United States branch profits tax on losses of a foreign subsidiary (1,813 ) 8.6 % — — % — — % State income tax expense, net of federal tax (benefit) expense 3,935 (18.6 %) 12,252 7.7 % (1,769 ) 3.2 % Establishment of deferred tax asset related to partnership basis difference (1) — — % — — % (3,501 ) 6.3 % Effect of permanent differences (138 ) 0.7 % 302 0.2 % (1,629 ) 2.9 % Tax effect of intercompany transactions (2) — — % (33,250 ) (21.0 %) — — % Tax credits (667 ) 3.2 % (6,897 ) (4.4 %) (9,607 ) 17.3 % Tax reform revaluation (3) — — % 288 0.2 % (15,894 ) 28.6 % (Decrease) increase in valuation allowance (4) (164 ) 0.8 % (20,434 ) (12.9 %) 21,023 (37.8 %) Other 154 (0.7 %) 1,416 0.9 % — — % Total income tax benefit $ (3,135 ) 15.0 % $ (13,027 ) (8.3 %) $ (30,836 ) 55.5 % (1) 2017 includes the establishment of a deferred tax asset related to partnership basis difference when it became apparent that it would reverse in the foreseeable future. This deferred tax asset was fully reserved in the valuation allowance described below as of December 31, 2017. (2) Effective January 1, 2017, we adopted a new accounting standard applicable to intercompany asset transfers. As a result, the accumulated unrecognized deferred tax expense associated with historical intercompany transfers was recognized as a cumulative effect adjustment through retained earnings at that time. 2018 includes the tax benefit to establish the initial deferred tax asset from the intercompany transfer of a portion of the Asset Management business between the Aimco Operating Partnership and TRS entities. (3) Reflects revaluation of deferred tax assets and liabilities using the TRS entities’ lower effective tax rates resulting from the 2017 Act. Accounting for the tax effects of enactment of the 2017 Act was finalized during the year ended December 31, 2018. (4) 2019 includes a $0.2 million release of a valuation allowance for expired state NOL carryforwards. 2017 includes a $15.4 million valuation allowance against the deferred tax assets associated with rehabilitation tax credits due to the lower federal tax rate under the 2017 Act. This valuation allowance was reversed in 2018 as a result of the sale of our Asset Management business. Income taxes paid totaled approximately $12.2 million, $11.5 million and $7.4 million in the years ended December 31, 2019, 2018, and 2017, respectively. For income tax purposes, dividends paid to holders of Common Stock primarily consist of ordinary income, capital gains, qualified dividends and unrecaptured Section 1250 gains, or a combination thereof. For the years ended December 31, 2019 , 2018 , and 2017 , dividends per share held for the entire year were estimated to be taxable as follows: 2019 2018 2017 Amount Percentage Amount Percentage Amount Percentage Ordinary income $ 0.66 20.7 % $ 0.51 33.4 % $ 0.75 51.5 % Capital gains 1.29 40.4 % 0.93 61.2 % 0.51 35.7 % Qualified dividends 0.66 20.7 % — — % 0.02 1.6 % Unrecaptured Section 1250 gain 0.58 18.2 % 0.08 5.4 % 0.16 11.2 % Total $ 3.19 100.0 % $ 1.52 100.0 % $ 1.44 100.0 %

Earnings per Share and per Unit

Earnings per Share and per Unit	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings per Share and per Unit	Note 11 — Earnings per Share and per Unit Aimco and the Aimco Operating Partnership calculate basic earnings per common share and basic earnings per common unit based on the weighted-average number of shares of Common Stock and common partnership units outstanding. We calculate diluted earnings per share and diluted earnings per unit taking into consideration dilutive common stock and common partnership unit equivalents and dilutive convertible securities outstanding during the period. Our common stock and common partnership unit equivalents include options to purchase shares of Common Stock, which, if exercised, would result in Aimco’s issuance of additional shares and the Aimco Operating Partnership’s issuance to Aimco of additional common partnership units equal to the number of shares purchased under the options. These equivalents also include unvested TSR Restricted Stock awards that do not meet the definition of participating securities, which would result in an increase in the number of shares of Common Stock and common partnership units outstanding equal to the number of the shares that vest. Common partnership unit equivalents also include unvested long-term incentive partnership units. We include in the denominator securities with dilutive effect in calculating diluted earnings per share and per unit during these periods. Our Time-Based Restricted Stock awards receive non-forfeitable dividends similar to shares of Common Stock and common partnership units prior to vesting, and our TSR LTIP I units and TSR LTIP II units receive non-forfeitable distributions based on specified percentages of the distributions paid to common partnership units prior to vesting and conversion. The unvested restricted shares and units related to these awards are participating securities. We include the effect of participating securities in basic and diluted earnings per share and unit computations using the two-class method of allocating distributed and undistributed earnings when the two-class method is more dilutive than the treasury stock method. Reconciliations of the numerator and denominator in the calculations of basic and diluted earnings per share and per unit for the years ended December 31, 2019, 2018, and 2017 are as follows (in thousands, except per share and per unit data): 2019 2018 2017 Earnings per share Numerator: Basic and dilutive net income attributable to Aimco common stockholders $ 466,144 $ 656,597 $ 306,861 Denominator - shares: Basic weighted-average Common Stock outstanding 147,718 151,152 151,595 Dilutive share equivalents outstanding 226 182 465 Dilutive weighted-average Common Stock outstanding 147,944 151,334 152,060 Earnings per share – basic $ 3.16 $ 4.34 $ 2.02 Earnings per share – dilutive $ 3.15 $ 4.34 $ 2.02 Non-dilutive share equivalents outstanding — 269 184 Earnings per unit Numerator: Basic and dilutive net income attributable to the Aimco Operating Partnership's common unitholders $ 492,177 $ 690,874 $ 321,300 Denominator - units Basic weighted-average common partnership units outstanding 155,882 158,890 158,793 Dilutive partnership unit equivalents outstanding 335 183 464 Dilutive weighted-average common partnership units outstanding 156,217 159,073 159,257 Earnings per unit – basic $ 3.16 $ 4.35 $ 2.02 Earnings per unit – dilutive $ 3.15 $ 4.34 $ 2.02 Non-dilutive partnership unit equivalents outstanding — 269 184 As discussed in Note 7, 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 December 31, 2019, these preferred OP Units were potentially redeemable for approximately 1.9 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.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 12 — Fair Value Measurements Recurring Fair Value Measurements We measure at fair value on a recurring basis our investment in the securitization trust that holds certain of our property debt, which These investments are presented within other assets in the consolidated balance sheets. 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. The following table summarizes fair value for our AFS debt securities as of December 31, 2019 and 2018 (in thousands): As of December 31, 2019 2018 Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 AFS debt securities $ 94,251 $ — $ 94,251 $ — $ 88,457 $ — $ 88,457 $ — Non-Recurring Fair Value Measurements We believe that the carrying value of the consolidated amounts of cash and cash equivalents, accounts receivables and payables approximated their fair value as of December 31, 2019 and 2018, due to their relatively short-term nature and high probability of realization. The carrying amounts of notes receivable and the revolving credit facility approximated their estimated fair value as of 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 valuation 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 of our non-recourse property debt as of December 31, 2019 and 2018 (in thousands): As of December 31, 2019 2018 Carrying Value Fair Value Carrying Value Fair Value Non-recourse property debt $ 4,251,339 $ 4,298,630 $ 3,937,000 $ 3,893,171

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Business Segments	Note 13 — Business Segments In 2019, as a result of the 2018 sale of the Asset Management business, we revised the information regularly reviewed by our chief executive officer, who is our chief operating decision maker, to assess our operating performance. We have determined we have four segments: Same Store, Redevelopment and Development, 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 that have not achieved a stabilized level of operations, 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 segment includes communities that we have acquired since the beginning of a two-year comparable period. Our Other Real Estate segment primarily includes communities that are subject to limitations on rent increases, communities that we expect to sell within 12 months but do not yet meet the criteria to be classified as held for sale, certain retail spaces and 1001 Brickell Bay Drive. Our chief operating decision maker uses proportionate property net operating income to assess the operating performance of our apartment communities. Proportionate property net operating income is defined as our share of rental and other property revenues, excluding utility costs reimbursed by residents, less our share of property operating expenses, net of utility reimbursements, for consolidated communities. In our consolidated statements of operations, utility reimbursements are included in rental and other property revenues attributable to real estate, in accordance with GAAP. As of December 31, 2019, our Same Store segment included 91 consolidated apartment communities with 26,649 apartment homes; our Redevelopment and Development segment included seven consolidated communities with 3,143 homes; our Acquisition segment included seven consolidated communities with 1,590 homes; and our Other Real Estate segment included 15 consolidated communities with 1,315 homes and one office building. The following tables present the revenues, proportionate property net operating income and income before income tax benefit of our segments on a proportionate basis and excluding our proportionate share of four apartment communities with 142 apartment homes that we neither manage nor consolidate, and amounts related to communities sold as of December 31, 2019 for the years ended December 31, 2019, 2018, and 2017 (in thousands): Same Store Redevelopment and Development Acquisition Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Year ended December 31, 2019: Total revenues $ 691,379 $ 75,522 $ 42,038 $ 45,105 $ 33,450 $ 26,800 $ 914,294 Property operating expenses attributable to real estate 181,802 27,919 11,715 17,717 31,140 40,928 311,221 Other operating expenses not allocated to segments (3) — — — — — 446,300 446,300 Total operating expenses 181,802 27,919 11,715 17,717 31,140 487,228 757,521 Proportionate property net operating income 509,577 47,603 30,323 27,388 2,310 (460,428 ) 156,773 Other items included in income before income tax benefit (4) — — — — — 348,119 348,119 Income before income tax benefit $ 509,577 $ 47,603 $ 30,323 $ 27,388 $ 2,310 $ (112,309 ) $ 504,892 Same Store Redevelopment and Development Acquisition Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Year ended December 31, 2018: Total revenues $ 665,835 $ 76,687 $ 27,923 $ 37,647 $ 31,442 $ 132,876 $ 972,410 Property operating expenses attributable to real estate 177,466 27,836 7,689 14,910 29,323 50,677 307,901 Other operating expenses not allocated to segments (3) — — — — — 448,753 448,753 Total operating expenses 177,466 27,836 7,689 14,910 29,323 499,430 756,654 Proportionate property net operating income 488,369 48,851 20,234 22,737 2,119 (366,554 ) 215,756 Other items included in income before income tax benefit (4) — — — — — 487,820 487,820 Income before income tax benefit $ 488,369 $ 48,851 $ 20,234 $ 22,737 $ 2,119 $ 121,266 $ 703,576 Same Store Redevelopment and Development Acquisition Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Year ended December 31, 2017: Total revenues $ 626,311 $ 72,995 $ — $ 36,869 $ 39,776 $ 229,486 $ 1,005,437 Property operating expenses attributable to real estate 171,167 26,471 — 14,121 29,782 77,585 319,126 Other operating expenses not allocated to segments (3) — — — — — 492,328 492,328 Total operating expenses 171,167 26,471 — 14,121 29,782 569,913 811,454 Proportionate property net operating income 455,144 46,524 — 22,748 9,994 (340,427 ) 193,983 Other items included in income before income tax benefit (4) — — — — — 122,260 122,260 Income before income tax benefit $ 455,144 $ 46,524 $ — $ 22,748 $ 9,994 $ (218,167 ) $ 316,243 (1) Represents adjustments for the noncontrolling interests in consolidated real estate partnerships’ share of the results of consolidated apartment 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 attributable to real estate in our 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, and the operating results of communities owned by consolidated partnerships served by our Asset Management business prior to its sale in July 2018. Corporate and Amounts Not Allocated to Segments 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. (3) Other operating expenses not allocated to segments consists of property operating expenses of partnerships served by our Asset Management business prior to its sale in July 2018, depreciation and amortization, general and administrative expenses and other operating expenses including provision for real estate impairment loss, which are not included in our measure of segment performance. (4) Other items included in income before income tax benefit primarily consists of gain on dispositions of real estate and the Asset Management business and interest expense. The assets of our segments and the consolidated assets not allocated to our segments were as follows (in thousands): December 31, 2019 December 31, 2018 Same Store $ 3,982,586 $ 4,068,880 Redevelopment and Development 946,390 792,126 Acquisition 623,037 507,190 Other Real Estate 647,725 327,092 Corporate and other assets (1) 629,001 494,716 Total consolidated assets $ 6,828,739 $ 6,190,004 (1) Includes the assets not allocated to our segments, primarily corporate assets, assets of apartment communities which were sold or classified as held for sale as of December 31, 2019, and the Asset Management business. For the years ended December 31, 2019, 2018, and 2017, capital additions related to our segments were as follows (in thousands): 2019 2018 2017 Same Store $ 153,944 $ 171,869 $ 215,130 Redevelopment and Development 194,498 138,103 84,712 Acquisition 33,122 14,228 — Other Real Estate 20,011 6,314 12,044 Total capital additions $ 401,575 $ 330,514 $ 311,886

Unaudited Summarized Consolidat

Unaudited Summarized Consolidated Quarterly Information	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Unaudited Summarized Consolidated Quarterly Information	Note 14 — Unaudited Summarized Consolidated Quarterly Information Aimco Aimco’s summarized unaudited consolidated quarterly information for the years ended December 31, 2019 and 2018, is provided below (in thousands, except per share amounts): Quarter 2019 First Second Third Fourth Total revenues $ 230,235 $ 224,200 $ 229,827 $ 230,032 Net income 291,295 69,996 3,970 142,766 Net income attributable to Aimco common stockholders 271,568 59,234 2,003 133,339 Net income attributable to Aimco common stockholders per common share – basic $ 1.88 $ 0.40 $ 0.01 $ 0.90 Net income attributable to Aimco common stockholders per common share – diluted $ 1.88 $ 0.40 $ 0.01 $ 0.90 Quarter 2018 First Second Third Fourth Total revenues $ 247,720 $ 250,187 $ 242,481 $ 232,022 Net income 95,690 7,156 603,917 9,840 Net income attributable to Aimco common stockholders 81,525 2,817 567,029 5,226 Net income attributable to Aimco common stockholders per common share – basic $ 0.54 $ 0.02 $ 3.73 $ 0.04 Net income attributable to Aimco common stockholders per common share – diluted $ 0.54 $ 0.02 $ 3.73 $ 0.04 The Aimco Operating Partnership The Aimco Operating Partnership’s summarized unaudited consolidated quarterly information for the years ended December 31, 2019 and 2018, is provided below (in thousands, except per unit amounts): Quarter 2019 First Second Third Fourth Total revenues $ 230,235 $ 224,200 $ 229,827 $ 230,032 Net income 291,295 69,996 3,970 142,766 Net income attributable to the Partnership’s common unitholders 286,639 62,817 2,138 140,583 Net income attributable to the Partnership’s common unitholders per common unit – basic $ 1.88 $ 0.40 $ 0.01 $ 0.90 Net income attributable to the Partnership’s common unitholders per common unit – diluted $ 1.88 $ 0.40 $ 0.01 $ 0.90 Quarter 2018 First Second Third Fourth Total revenues $ 247,720 $ 250,187 $ 242,481 $ 232,022 Net income 95,690 7,156 603,917 9,840 Net income attributable to the Partnership’s common unitholders 85,274 2,949 597,100 5,551 Net income attributable to the Partnership’s common unitholders per common unit – basic $ 0.54 $ 0.02 $ 3.73 $ 0.04 Net income attributable to the Partnership’s common unitholders per common unit – diluted $ 0.54 $ 0.02 $ 3.72 $ 0.04

Schedule III_ Real Estate and

Schedule III: Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2019
Real Estate And Accumulated Depreciation Disclosure [Abstract]
Schedule III: Real Estate and Accumulated Depreciation	APARTMENT INVESTMENT AND MANAGEMENT COMPANY AIMCO PROPERTIES, L.P. SCHEDULE III: REAL ESTATE AND ACCUMULATED DEPRECIATION December 31, 2019 (In Thousands Except Apartment Home Data) (2) As of December 31, 2019 (1) Initial Cost Cost Capitalized (4) Apartment Date Year Apartment Buildings and Subsequent to Buildings and (3) Accumulated Total Cost (5) Apartment Community Name Type Consolidated Location Built Homes Land Improvements Consolidation Land Improvements Total Depreciation (AD) Net of AD Encumbrances Same Store Sales: 100 Forest Place High Rise Dec 1997 Oak Park, IL 1987 234 $ 2,664 $ 18,815 $ 11,145 $ 2,664 $ 29,960 $ 32,624 $ (16,676 ) $ 15,948 $ 34,453 118-122 West 23rd Street High Rise Jun 2012 New York, NY 1987 42 14,985 23,459 6,914 14,985 30,373 45,358 (10,461 ) 34,897 16,999 1045 on the Park Apartment Homes Mid Rise Jul 2013 Atlanta, GA 2012 30 2,793 6,662 819 2,793 7,481 10,274 (1,739 ) 8,535 — 1582 First Avenue High Rise Mar 2005 New York, NY 1900 17 4,281 752 518 4,281 1,270 5,551 (650 ) 4,901 2,226 21 Fitzsimons Mid Rise Aug 2014 Aurora, CO 2008 600 12,864 104,720 27,677 12,864 132,397 145,261 (26,098 ) 119,163 89,413 2200 Grace Mid Rise Dec 1999 Lombard, IL 1971 72 642 7,788 294 642 8,082 8,724 (4,549 ) 4,175 7,448 2900 on First Apartments Mid Rise Oct 2008 Seattle, WA 1989 135 19,070 17,518 34,356 19,070 51,874 70,944 (29,578 ) 41,366 13,594 306 East 89th Street High Rise Jul 2004 New York, NY 1930 20 2,680 1,006 1,099 2,680 2,105 4,785 (1,046 ) 3,739 1,816 322-324 East 61st Street High Rise Mar 2005 New York, NY 1900 40 6,372 2,224 1,598 6,372 3,822 10,194 (2,009 ) 8,185 3,339 3400 Avenue of the Arts Mid Rise Mar 2002 Costa Mesa, CA 1987 770 57,241 65,506 88,112 57,241 153,618 210,859 (92,205 ) 118,654 142,476 452 East 78th Street High Rise Jan 2004 New York, NY 1900 12 1,982 608 600 1,982 1,208 3,190 (548 ) 2,642 — 510 East 88th Street High Rise Jan 2004 New York, NY 1900 20 3,163 1,002 653 3,163 1,655 4,818 (726 ) 4,092 — 514-516 East 88th Street High Rise Mar 2005 New York, NY 1900 36 6,282 2,168 1,617 6,282 3,785 10,067 (1,868 ) 8,199 3,620 Axiom Mid Rise Apr 2015 Cambridge, MA 2015 115 — 63,612 2,665 — 66,277 66,277 (11,504 ) 54,773 32,253 Bank Lofts High Rise Apr 2001 Denver, CO 1920 125 3,525 9,045 5,797 3,525 14,842 18,367 (8,109 ) 10,258 10,218 Bay Ridge at Nashua Garden Jan 2003 Nashua, NH 1984 412 3,262 40,713 17,995 3,262 58,708 61,970 (26,731 ) 35,239 50,638 Bayberry Hill Estates Garden Aug 2002 Framingham, MA 1971 424 19,944 35,945 25,151 19,944 61,096 81,040 (30,503 ) 50,537 44,197 Bluffs at Pacifica, The Garden Oct 2006 Pacifica, CA 1963 64 8,108 4,132 17,349 8,108 21,481 29,589 (11,400 ) 18,189 — Boston Lofts High Rise Apr 2001 Denver, CO 1890 158 3,446 20,589 6,715 3,446 27,304 30,750 (14,706 ) 16,044 14,927 Boulder Creek Garden Jul 1994 Boulder, CO 1973 221 754 7,730 20,791 754 28,521 29,275 (20,708 ) 8,567 37,861 Broadcast Center Garden Mar 2002 Los Angeles, CA 1990 279 29,407 41,244 31,856 29,407 73,100 102,507 (32,455 ) 70,052 96,880 Broadway Lofts High Rise Sep 2012 San Diego, CA 1909 84 5,367 14,442 7,647 5,367 22,089 27,456 (6,031 ) 21,425 11,298 Burke Shire Commons Garden Mar 2001 Burke, VA 1986 360 4,867 23,617 19,855 4,867 43,472 48,339 (27,328 ) 21,011 56,855 Calhoun Beach Club High Rise Dec 1998 Minneapolis, MN 1928 332 11,708 73,334 65,713 11,708 139,047 150,755 (85,259 ) 65,496 — Canyon Terrace Garden Mar 2002 Saugus, CA 1984 130 7,508 6,601 7,008 7,508 13,609 21,117 (7,711 ) 13,406 — Cedar Rim Garden Apr 2000 Newcastle, WA 1980 104 761 5,218 13,873 761 19,091 19,852 (14,179 ) 5,673 — Charlesbank Apartment Homes Mid Rise Sep 2013 Watertown, MA 2012 44 3,399 11,726 1,018 3,399 12,744 16,143 (2,931 ) 13,212 — Chestnut Hall High Rise Oct 2006 Philadelphia, PA 1923 315 12,338 14,299 13,223 12,338 27,522 39,860 (13,266 ) 26,594 35,834 Creekside Garden Jan 2000 Denver, CO 1974 328 3,189 12,698 7,404 3,189 20,102 23,291 (13,579 ) 9,712 11,066 Crescent at West Hollywood, The Mid Rise Mar 2002 West Hollywood, CA 1985 130 15,765 10,215 8,281 15,765 18,496 34,261 (12,337 ) 21,924 39,336 Elm Creek Mid Rise Dec 1997 Elmhurst, IL 1987 400 5,910 30,830 32,788 5,910 63,618 69,528 (35,969 ) 33,559 50,296 Evanston Place High Rise Dec 1997 Evanston, IL 1990 190 3,232 25,546 16,703 3,232 42,249 45,481 (20,982 ) 24,499 — Four Quarters Habitat Garden Jan 2006 Miami, FL 1976 336 2,379 17,199 32,991 2,379 50,190 52,569 (30,456 ) 22,113 50,716 Foxchase Garden Dec 1997 Alexandria, VA 1940 2,113 15,496 96,062 64,213 15,496 160,275 175,771 (92,368 ) 83,403 218,337 Georgetown Garden Aug 2002 Framingham, MA 1964 207 12,351 13,168 4,896 12,351 18,064 30,415 (9,068 ) 21,347 14,355 Georgetown II Mid Rise Aug 2002 Framingham, MA 1958 72 4,577 4,057 2,316 4,577 6,373 10,950 (3,871 ) 7,079 — Hidden Cove Garden Jul 1998 Escondido, CA 1983 334 3,043 17,616 11,447 3,043 29,063 32,106 (17,321 ) 14,785 51,840 Hidden Cove II Garden Jul 2007 Escondido, CA 1986 118 12,849 6,530 5,439 12,849 11,969 24,818 (5,881 ) 18,937 20,160 Hillcreste Garden Mar 2002 Century City, CA 1989 315 35,862 47,216 15,706 35,862 62,922 98,784 (29,709 ) 69,075 61,930 Hillmeade Garden Nov 1994 Nashville, TN 1986 288 2,872 16,070 22,103 2,872 38,173 41,045 (22,434 ) 18,611 26,756 Horizons West Apartments Mid Rise Dec 2006 Pacifica, CA 1970 78 8,887 6,377 2,808 8,887 9,185 18,072 (4,155 ) 13,917 — Hunt Club Garden Sep 2000 Gaithersburg, MD 1986 336 17,859 13,149 14,807 17,859 27,956 45,815 (17,241 ) 28,574 — Hyde Park Tower High Rise Oct 2004 Chicago, IL 1990 155 4,731 14,927 16,765 4,731 31,692 36,423 (11,613 ) 24,810 12,301 Indian Oaks Garden Mar 2002 Simi Valley, CA 1986 254 24,523 15,801 12,124 24,523 27,925 52,448 (14,829 ) 37,619 26,944 Indigo High Rise Aug 2016 Redwood City, CA 2016 463 26,932 296,116 3,561 26,932 299,677 326,609 (35,408 ) 291,201 135,348 Island Club Garden Oct 2000 Oceanside, CA 1986 592 18,027 28,654 21,829 18,027 50,483 68,510 (32,842 ) 35,668 93,333 Latrobe High Rise Jan 2003 Washington, D.C. 1980 175 3,459 9,103 13,380 3,459 22,483 25,942 (13,313 ) 12,629 26,128 Laurel Crossing Garden Jan 2006 San Mateo, CA 1971 418 49,474 17,756 15,017 49,474 32,773 82,247 (17,078 ) 65,169 104,658 Lincoln Place (6) Garden Oct 2004 Venice, CA 1951 795 128,332 10,439 340,136 44,197 350,575 394,772 (143,166 ) 251,606 184,330 Malibu Canyon Garden Mar 2002 Calabasas, CA 1986 698 69,834 53,438 41,577 69,834 95,015 164,849 (51,078 ) 113,771 102,968 Mariners Cove Garden Mar 2002 San Diego, CA 1984 500 — 66,861 14,977 — 81,838 81,838 (42,171 ) 39,667 — Meadow Creek Garden Jul 1994 Boulder, CO 1968 332 1,435 24,533 10,058 1,435 34,591 36,026 (21,082 ) 14,944 — Merrill House High Rise Jan 2000 Falls Church, VA 1964 159 1,836 10,831 7,588 1,836 18,419 20,255 (10,923 ) 9,332 — Monterey Grove Garden Jun 2008 San Jose, CA 1999 224 34,325 21,939 16,051 34,325 37,990 72,315 (13,236 ) 59,079 49,680 Ocean House on Prospect Mid Rise Apr 2013 La Jolla, CA 1970 53 12,528 18,805 15,336 12,528 34,141 46,669 (8,635 ) 38,034 12,281 (2) As of December 31, 2019 (1) Initial Cost Cost Capitalized (4) Apartment Date Year Apartment Buildings and Subsequent to Buildings and (3) Accumulated Total Cost (5) Apartment Community Name Type Consolidated Location Built Homes Land Improvements Consolidation Land Improvements Total Depreciation (AD) Net of AD Encumbrances One Canal High Rise Sep 2013 Boston, MA 2016 310 $ — $ 15,873 $ 178,772 $ — $ 194,645 $ 194,645 $ (29,058 ) $ 165,587 $ 108,491 Pacific Bay Vistas (6) Garden Mar 2001 San Bruno, CA 1987 308 28,694 62,460 40,698 23,354 103,158 126,512 (39,188 ) 87,324 104,664 Pacifica Park Garden Jul 2006 Pacifica, CA 1977 104 12,970 6,579 8,815 12,970 15,394 28,364 (7,517 ) 20,847 28,613 Palazzo at Park La Brea, The Mid Rise Feb 2004 Los Angeles, CA 2002 521 48,362 125,464 48,103 48,362 173,567 221,929 (87,785 ) 134,144 165,344 Palazzo East at Park La Brea, The Mid Rise Mar 2005 Los Angeles, CA 2005 611 72,578 136,503 28,065 72,578 164,568 237,146 (79,668 ) 157,478 192,083 Pathfinder Village Garden Jan 2006 Fremont, CA 1973 246 19,595 14,838 20,707 19,595 35,545 55,140 (17,480 ) 37,660 55,000 Peachtree Park Garden Jan 1996 Atlanta, GA 1969 303 4,684 11,713 14,244 4,684 25,957 30,641 (17,244 ) 13,397 27,316 Plantation Gardens Garden Oct 1999 Plantation, FL 1971 372 3,773 19,443 25,547 3,773 44,990 48,763 (28,766 ) 19,997 — Preserve at Marin Mid Rise Aug 2011 Corte Madera, CA 1964 126 13,516 30,132 82,512 13,516 112,644 126,160 (32,015 ) 94,145 35,451 Ravensworth Towers High Rise Jun 2004 Annandale, VA 1974 219 3,455 17,157 4,575 3,455 21,732 25,187 (15,171 ) 10,016 19,870 River Club, The Garden Apr 2005 Edgewater, NJ 1998 266 30,579 30,638 8,468 30,579 39,106 69,685 (19,159 ) 50,526 59,070 Riverloft High Rise Oct 1999 Philadelphia, PA 1910 184 2,120 11,286 38,090 2,120 49,376 51,496 (25,765 ) 25,731 5,881 Rosewood Garden Mar 2002 Camarillo, CA 1976 152 12,430 8,060 6,983 12,430 15,043 27,473 (7,950 ) 19,523 — Royal Crest Estates Garden Aug 2002 Warwick, RI 1972 492 22,433 24,095 6,736 22,433 30,831 53,264 (21,454 ) 31,810 — Royal Crest Estates Garden Aug 2002 Nashua, NH 1970 902 68,230 45,562 16,865 68,230 62,427 130,657 (44,966 ) 85,691 70,299 Royal Crest Estates Garden Aug 2002 Marlborough, MA 1970 473 25,178 28,786 15,100 25,178 43,886 69,064 (29,314 ) 39,750 62,074 Royal Crest Estates Garden Aug 2002 North Andover, MA 1970 588 51,292 36,808 30,314 51,292 67,122 118,414 (39,455 ) 78,959 81,363 Saybrook Pointe Garden Dec 2014 San Jose, CA 1995 324 32,842 84,457 25,960 32,842 110,417 143,259 (19,010 ) 124,249 61,073 Shenandoah Crossing Garden Sep 2000 Fairfax, VA 1984 640 18,200 57,198 26,395 18,200 83,593 101,793 (62,964 ) 38,829 57,204 Springwoods at Lake Ridge Garden Jul 2002 Woodbridge, VA 1984 180 5,587 7,284 3,790 5,587 11,074 16,661 (5,064 ) 11,597 — Sterling Apartment Homes, The Garden Oct 1999 Philadelphia, PA 1961 534 8,871 55,365 118,250 8,871 173,615 182,486 (91,452 ) 91,034 141,077 Stonecreek Club Garden Sep 2000 Germantown, MD 1984 240 13,593 9,347 8,450 13,593 17,797 31,390 (13,092 ) 18,298 — Township At Highlands Town Home Nov 1996 Centennial, CO 1985 161 1,536 9,773 10,121 1,536 19,894 21,430 (13,167 ) 8,263 13,120 Vantage Pointe Mid Rise Aug 2002 Swampscott, MA 1987 96 4,748 10,089 2,661 4,748 12,750 17,498 (5,806 ) 11,692 — Villa Del Sol Garden Mar 2002 Norwalk, CA 1972 120 7,476 4,861 5,050 7,476 9,911 17,387 (6,000 ) 11,387 10,338 Villas of Pasadena Mid Rise Jan 2006 Pasadena, CA 1973 92 9,693 6,818 4,696 9,693 11,514 21,207 (5,230 ) 15,977 — Vivo High Rise Jun 2016 Cambridge, MA 2015 91 6,450 35,974 5,851 6,450 41,825 48,275 (11,588 ) 36,687 19,810 Waterford Village Garden Aug 2002 Bridgewater, MA 1971 588 29,110 28,101 11,636 29,110 39,737 68,847 (29,186 ) 39,661 34,464 Waterways Village Garden Jun 1997 Aventura, FL 1994 180 4,504 11,064 16,910 4,504 27,974 32,478 (13,996 ) 18,482 12,865 Waverly Apartments Garden Aug 2008 Brighton, MA 1970 103 7,920 11,347 6,844 7,920 18,191 26,111 (7,441 ) 18,670 11,245 Wexford Village Garden Aug 2002 Worcester, MA 1974 264 6,349 17,939 5,183 6,349 23,122 29,471 (14,281 ) 15,190 — Willow Bend Garden May 1998 Rolling Meadows, IL 1969 328 2,717 15,437 20,130 2,717 35,567 38,284 (24,855 ) 13,429 32,489 Windrift Garden Mar 2001 Oceanside, CA 1987 404 24,960 17,590 22,254 24,960 39,844 64,804 (26,130 ) 38,674 72,646 Windsor Park Garden Mar 2001 Woodbridge, VA 1987 220 4,279 15,970 6,366 4,279 22,336 26,615 (14,287 ) 12,328 — Yacht Club at Brickell High Rise Dec 2003 Miami, FL 1998 357 31,362 32,214 18,825 31,362 51,039 82,401 (19,678 ) 62,723 68,351 Yorktown Apartments High Rise Dec 1999 Lombard, IL 1971 292 2,413 10,374 53,236 2,413 63,610 66,023 (31,274 ) 34,749 30,167 Total Same Store Sales 26,649 $ 1,411,619 $ 2,597,010 $ 2,149,561 $ 1,322,144 $ 4,746,571 $ 6,068,715 $ (2,188,175 ) $ 3,880,540 $ 3,579,476 Redevelopment and Development: 236-238 East 88th Street High Rise Jan 2004 New York, NY 1900 42 $ 8,820 $ 2,914 $ 8,734 $ 8,820 $ 11,648 $ 20,468 $ (2,088 ) $ 18,380 $ — 707 Leahy Garden Apr 2007 Redwood City, CA 1973 110 15,444 7,909 16,619 15,444 24,528 39,972 (6,731 ) 33,241 8,534 Bay Parc Plaza High Rise Sep 2004 Miami, FL 2000 474 22,680 41,847 38,851 22,680 80,698 103,378 (26,606 ) 76,772 76,631 Flamingo Point High Rise Sep 1997 Miami Beach, FL 1960 1,101 32,427 48,808 400,164 32,427 448,972 481,399 (188,572 ) 292,827 — Parc Mosaic Garden Dec 2014 Boulder, CO 1970 226 15,300 — 107,179 15,300 107,179 122,479 (461 ) 122,018 — Park Towne Place High Rise Apr 2000 Philadelphia, PA 1959 940 10,472 47,301 353,053 10,472 400,354 410,826 (152,223 ) 258,603 196,655 Villas at Park La Brea, The Garden Mar 2002 Los Angeles, CA 2002 250 8,630 48,871 19,251 8,630 68,122 76,752 (33,834 ) 42,918 51,097 Other (7) — 9,598 — 82,830 9,598 82,830 92,428 (2 ) 92,426 — Total Redevelopment and Development 3,143 $ 123,371 $ 197,650 $ 1,026,681 $ 123,371 $ 1,224,331 $ 1,347,702 $ (410,517 ) $ 937,185 $ 332,917 Acquisition: 777 South Broad Street Mid Rise May 2018 Philadelphia, PA 2010 146 $ 6,986 $ 67,512 $ 2,596 $ 6,986 $ 70,108 $ 77,094 $ (4,115 ) $ 72,979 $ 56,581 Avery Row Mid Rise Dec 2018 Arlington, VA 2013 67 8,165 21,348 1,812 8,165 23,160 31,325 (913 ) 30,412 — Bent Tree Apartments Garden Feb 2018 Centreville, VA 1986 748 46,975 113,695 20,823 46,975 134,518 181,493 (9,679 ) 171,814 — Locust on the Park High Rise May 2018 Philadelphia, PA 1911 152 5,292 53,823 4,228 5,292 58,051 63,343 (3,510 ) 59,833 34,891 One Ardmore Mid Rise Apr 2019 Ardmore, PA 2019 110 4,929 61,631 1,387 4,929 63,018 67,947 (1,560 ) 66,387 31,052 Southstar Lofts High Rise May 2018 Philadelphia, PA 2014 85 1,780 37,428 683 1,780 38,111 39,891 (2,235 ) 37,656 29,624 The Left Bank Mid Rise May 2018 Philadelphia, PA 1929 282 — 130,893 13,352 — 144,245 144,245 (8,092 ) 136,153 80,679 Other (7) — 7,890 — 14,634 7,890 14,634 22,524 — 22,524 — Total Acquisition 1,590 $ 82,017 $ 486,330 $ 59,515 $ 82,017 $ 545,845 $ 627,862 $ (30,104 ) $ 597,758 $ 232,827 (2) As of December 31, 2019 (1) Initial Cost Cost Capitalized (4) Apartment Date Year Apartment Buildings and Subsequent to Buildings and (3) Accumulated Total Cost (5) Apartment Community Name Type Consolidated Location Built Homes Land Improvements Consolidation Land Improvements Total Depreciation (AD) Net of AD Encumbrances Other Real Estate: 1001 Brickell High Rise Jul 2019 Miami, FL 1985 — $ 149,519 $ 152,892 $ 5,228 $ 149,519 $ 158,120 $ 307,639 $ (8,053 ) $ 299,586 $ — 173 E. 90th Street High Rise May 2004 New York, NY 1910 72 12,066 4,535 8,827 12,066 13,362 25,428 (4,667 ) 20,761 — 182-188 Columbus Avenue Mid Rise Feb 2007 New York, NY 1910 32 19,123 3,300 5,769 19,123 9,069 28,192 (4,603 ) 23,589 13,635 234 East 88th Street Mid Rise Jan 2014 New York, NY 1900 20 2,448 4,449 828 2,448 5,277 7,725 (1,418 ) 6,307 — 237-239 Ninth Avenue High Rise Mar 2005 New York, NY 1900 36 8,495 1,866 3,132 8,495 4,998 13,493 (3,166 ) 10,327 5,438 240 West 73rd Street High Rise Sep 2004 New York, NY 1900 200 68,109 12,140 14,048 68,109 26,188 94,297 (10,715 ) 83,582 — 311 & 313 East 73rd Street Mid Rise Mar 2003 New York, NY 1904 34 5,678 1,609 598 5,678 2,207 7,885 (1,625 ) 6,260 — 464-466 Amsterdam & 200-210 W. 83rd Street Mid Rise Feb 2007 New York, NY 1910 71 25,553 7,101 9,153 25,553 16,254 41,807 (6,396 ) 35,411 20,094 518 East 88th Street Mid Rise Jan 2014 New York, NY 1900 20 2,233 4,315 625 2,233 4,940 7,173 (1,388 ) 5,785 — Columbus Avenue Mid Rise Sep 2003 New York, NY 1880 59 35,527 9,450 9,327 35,527 18,777 54,304 (12,118 ) 42,186 24,608 Heritage Park Escondido Garden Oct 2000 Escondido, CA 1986 196 1,055 7,565 2,945 1,055 10,510 11,565 (7,188 ) 4,377 5,867 Heritage Park Livermore Garden Oct 2000 Livermore, CA 1988 167 — 10,209 2,111 — 12,320 12,320 (8,576 ) 3,744 6,090 Heritage Village Anaheim Garden Oct 2000 Anaheim, CA 1986 196 1,832 8,541 2,332 1,832 10,873 12,705 (7,339 ) 5,366 7,124 Mezzo High Rise Mar 2015 Atlanta, GA 2008 94 4,292 34,178 1,817 4,292 35,995 40,287 (6,918 ) 33,369 22,970 St. George Villas Garden Jan 2006 St. George, SC 1984 40 107 1,025 419 107 1,444 1,551 (1,290 ) 261 293 Tremont Mid Rise Dec 2014 Atlanta, GA 2009 78 5,274 18,011 3,069 5,274 21,080 26,354 (4,028 ) 22,326 — Other (7) — 205 — 382 205 382 587 — 587 — Total Other Real Estate 1,315 $ 341,516 $ 281,186 $ 70,610 $ 341,516 $ 351,796 $ 693,312 $ (89,488 ) $ 603,824 $ 106,119 Total Portfolio 32,697 $ 1,958,523 $ 3,562,176 $ 3,306,367 $ 1,869,048 $ 6,868,543 $ 8,737,591 $ (2,718,284 ) $ 6,019,307 $ 4,251,339 (1) Date we acquired the apartment community or first consolidated the partnership that owns the community. (2) Includes costs capitalized since acquisition or date of initial consolidation of the community. (3) The aggregate cost of land and depreciable property for federal income tax purposes was approximately $3.8 billion as of December 31, 2019. (4) Depreciable life for buildings and improvements ranges from 5 to 30 years and is calculated on a straight-line basis. (5) Encumbrances are presented before reduction for debt issuance costs. (6) The current carrying value of the apartment community reflects an impairment loss recognized during prior periods. (7) Other includes apartment communities under development, land parcels, and certain non-residential properties held for future development. APARTMENT INVESTMENT AND MANAGEMENT COMPANY AIMCO PROPERTIES, L.P. SCHEDULE III: REAL ESTATE AND ACCUMULATED DEPRECIATION For the Years Ended December 31, 2019, 2018, and 2017 (In Thousands) 2019 2018 2017 Total real estate balance at beginning of year $ 8,308,590 $ 8,478,877 $ 8,486,166 Additions during the year: Acquisitions 383,557 501,009 16,687 Capital additions 404,896 348,727 354,229 Dispositions and other (359,452 ) (1,020,023 ) (378,205 ) Total real estate balance at end of year $ 8,737,591 $ 8,308,590 $ 8,478,877 Accumulated depreciation balance at beginning of year $ 2,585,115 $ 2,848,609 $ 2,730,758 Depreciation 358,661 354,208 344,960 Dispositions and other (225,492 ) (617,702 ) (227,109 ) Accumulated depreciation balance at end of year $ 2,718,284 $ 2,585,115 $ 2,848,609

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation Aimco’s accompanying consolidated financial statements include the accounts of Aimco, the Aimco Operating Partnership and their consolidated subsidiaries. The Aimco Operating Partnership’s consolidated financial statements include the accounts of the Aimco Operating Partnership and its consolidated subsidiaries. All significant intercompany balances have been eliminated in consolidation. 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 of December 31, 2019 and 2018, Aimco consolidated six and nine VIEs, respectively, including the Aimco Operating Partnership 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.
Noncontrolling Interests in the Aimco Operating Partnership	Noncontrolling Interests in the Aimco Operating Partnership Noncontrolling interests in Aimco Operating Partnership consist of common OP Units and preferred OP Units and are reflected in Aimco’s accompanying consolidated balance sheets as noncontrolling interests in Aimco Operating Partnership. Holders of preferred OP Units participate in the Aimco Operating Partnership’s income or loss only to the extent of their preferred distributions. Within Aimco’s consolidated financial statements, after provision for preferred OP Unit distributions, the Aimco Operating Partnership’s income or loss is allocated to the holders of common OP Units based on the weighted-average number of common OP Units (including those held by Aimco) outstanding during the period. During the years ended December 31, 2019, 2018, and 2017, the holders of common OP Units had a weighted-average ownership interest in the Aimco Operating Partnership of 6.0%, 4.9%, and 4.5%, respectively. Please refer to Note 8 for further information regarding the items comprising noncontrolling interests in the Aimco Operating Partnership. Substantially all of the assets and liabilities of Aimco are those of the Aimco Operating Partnership.
Noncontrolling Interests in Consolidated Real Estate Partnerships	Noncontrolling Interests in Consolidated Real Estate Partnerships We generally report the unaffiliated partners’ interests in the net assets of our consolidated real estate partnerships as noncontrolling interests in consolidated real estate partnerships within consolidated equity and partners’ capital. If a real estate partnership includes redemption rights that are not within Aimco and the Aimco Operating Partnership’s control, the noncontrolling interest is included as temporary equity or temporary capital. If the redemption right is not currently redeemable but probable of being redeemable in the future, changes in redemption value are recognized each quarter with the change in value being reflected in additional paid-in-capital. The assets of real estate partnerships consolidated by the Aimco Operating Partnership must first be used to settle the liabilities of such consolidated real estate partnerships. These consolidated real estate partnerships’ creditors do not have recourse to the general credit of the Aimco Operating Partnership. Noncontrolling interests in consolidated real estate partnerships consist primarily of equity interests held by limited partners in consolidated real estate partnerships that have finite lives. We generally attribute to noncontrolling interests their share of income or loss of consolidated partnerships based on their proportionate interest in the results of operations of the partnerships, including their share of losses even if such attribution results in a deficit noncontrolling interest balance within our equity and partners’ capital accounts. The terms of the related partnership agreements generally require the partnerships to be liquidated following the sale of the underlying real estate. As the general partner in these partnerships, we ordinarily control the execution of real estate sales and other events that could lead to the liquidation, redemption or other settlement of noncontrolling interests. Changes in our ownership interest in consolidated real estate partnerships generally consist of our purchase of an additional interest in or the sale of our entire interest in a consolidated real estate partnership. The effect on our equity and partners’ capital of our purchase of additional interests in consolidated real estate partnerships during the years ended December 31, 2019, 2018, and 2017, is shown in our consolidated statements of equity and partners’ capital. The effect on our equity and partners’ capital of sales of consolidated real estate or sales of our entire interest in consolidated real estate partnerships is reflected in our consolidated financial statements as gains or losses on dispositions of real estate and accordingly the effect on our equity and partners’ capital is reflected within the amount of net income allocated to us and to noncontrolling interests. Upon our deconsolidation of a real estate partnership following the sale of our partnership interests or liquidation of the partnership following sale of the related apartment community, we derecognize any remaining noncontrolling interest of the associated partnership previously recorded in our consolidated balance sheets.
Investments	Investments in Unconsolidated Real Estate Partnerships We own general and limited partner interests in partnerships that either directly, or through interests in other real estate partnerships, own apartment communities. We generally account for investments in real estate partnerships that we do not consolidate under the equity method. Under the equity method, we recognize our share of the earnings or losses of the entity for the periods presented, inclusive of our share of any impairments and disposition gains or losses recognized by and related to such entities, and we present such amounts within income from unconsolidated real estate partnerships in our consolidated statements of operations. The excess of our cost of the acquired partnership interests over our share of the partners’ equity or deficit is generally ascribed to the fair values of land and buildings owned by the partnerships. We amortize the excess cost ascribed to the buildings over the related estimated useful lives. Such amortization is recorded as an adjustment of the amounts of earnings or losses we recognize from such unconsolidated real estate partnerships. We may also originate loans for real estate acquisitions or developments where we either expect, or have the opportunity, to participate in the residual profits from such projects. When the risks and rewards of these arrangements are similar to an equity investor or joint venture partner, we account for these arrangements as real estate investments using the equity method of accounting. We recognize as income changes in our share of net assets, adjusted for any basis differential, in mezzanine investment income, net, in our consolidated statements of operations. Investments in Securitization Trust that holds Aimco Property Debt We hold investments in a securitization trust that primarily holds certain of our property debt. These investments were initially recognized at their purchase price and the discount to the face value is being accreted into interest income over the expected term of the securities. We have designated these investments as available for sale, or AFS, debt securities and we measure these investments at fair value with changes in their fair value, other than the changes attributed to the accretion described above, recognized as an adjustment of accumulated other comprehensive income or loss within equity and partners’ capital. Please refer to Note 12 for further information regarding these debt securities.
Real Estate	Real Estate Acquisitions Upon the acquisition of real estate, we determine whether the purchase qualifies as an asset acquisition or, less frequently, meets the definition of an acquisition of a business. We generally recognize the acquisition of apartment communities or interests in partnerships that own communities at our cost, including the related transaction costs, as asset acquisitions. We allocate the cost of apartment communities acquired based on the relative fair value of the assets acquired and liabilities assumed. The fair value of these assets and liabilities is determined using valuation techniques that rely on Level 2 and Level 3 inputs within the fair value framework. We determine the fair value of tangible assets, such as land, buildings, furniture, fixtures and equipment using valuation techniques that consider comparable market transactions, replacement costs and other available information. We determine the fair value of identified intangible assets or liabilities, which typically relate to in-place leases, using valuation techniques that consider the terms of the in-place leases, current market data for comparable leases and our experience in leasing similar communities. The intangible assets or liabilities related to in-place leases are comprised of: (a) the value of the above- and below-market leases in-place, measured over the period, including probable lease renewals for below-market leases, that the leases are expected to remain in effect; (b) the estimated unamortized portion of avoided leasing commissions and other costs that ordinarily would be incurred to originate the in-place leases; and (c) the value associated with leased apartment homes during an estimated absorption period, which estimates rental revenue that would not have been earned had leased apartment homes been vacant at the time of acquisition, assuming lease-up periods based on market demand and stabilized occupancy levels. The above- and below-market lease intangibles are amortized to rental revenue over the expected remaining terms of the associated leases, which include reasonably assured renewal periods. Other intangible assets related to in-place leases are amortized to depreciation and amortization over the expected remaining terms of the associated leases. Capital Additions We capitalize costs, including certain indirect costs, incurred in connection with our capital additions activities, including redevelopments, developments, other tangible apartment community improvements, and replacements of existing apartment community components. Included in these capitalized costs are payroll costs associated with time spent by employees in connection with capital additions activities at the apartment community level. We characterize as “indirect costs” an allocation of certain department costs, including payroll, at the area operations and corporate levels that clearly relate to capital additions activities. We also capitalize interest, property taxes, and insurance during periods in which construction projects are in progress. We begin capitalization of costs, including certain indirect costs, incurred in connection with our capital addition activities, upon commencement of activities necessary to ready apartment communities for their intended use. These activities include when apartment communities or apartment homes are undergoing physical construction, as well as when homes are held vacant in advance of planned construction, provided that other activities such as permitting, planning and design are in progress. We cease the capitalization of costs when the apartment communities are substantially complete and ready for their intended use, which is typically when construction has been substantially completed and apartment homes are available for occupancy. Costs, including ordinary repairs, maintenance, and resident turnover costs, are charged to property operating expense as incurred. For the years ended December 31, 2019, 2018, and 2017, we capitalized to buildings and improvements $11.8 million, $7.6 million, and $7.6 million of interest costs, respectively, and $37.8 million, $36.8 million, and $36.0 million of other direct and indirect costs, respectively. Gain or Loss on Dispositions Gain or loss on real estate dispositions are recognized when we no longer hold a controlling financial interest in the real estate and sufficient consideration has been received. Upon disposition, the related assets and liabilities are derecognized, and the gain or loss on disposition is recognized as the difference between the carrying amount of those assets and liabilities and the value of consideration received. Impairment Real estate and other long-lived assets to be held and used are stated at cost, less accumulated depreciation and amortization, unless the carrying amount of the asset is not recoverable. If events or circumstances indicate that the carrying amount of an apartment community may not be recoverable, we assess its recoverability by comparing the carrying amount to our estimate of the undiscounted future cash flows, excluding interest charges, of the community. If the carrying amount exceeds the aggregate undiscounted future cash flows, we recognize an impairment loss to the extent the carrying amount exceeds the estimated fair value of the community. As a result of our analysis, we did not recognize an impairment of our real estate and other long-lived assets to be held and used during the year ended December 31, 2019 and December 31, 2018. During the year ended December 31, 2017 we recognized an impairment related to our La Jolla Cove property, which we sold in 2018.
Cash Equivalents and Restricted Cash	Cash Equivalents We classify highly liquid investments with an original maturity of three months or less as cash equivalents. We maintain cash equivalents in financial institutions in excess of insured limits. We have not experienced any losses in these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions. Restricted Cash Restricted cash includes capital replacement reserves, completion repair reserves, bond sinking fund amounts, real estate tax and insurance escrow accounts held by lenders and resident security deposits.
Other Assets	Other Assets As of December 31, 2019 and 2018, other assets was comprised of the following amounts (in thousands): 2019 2018 Investments in securitization trust that holds Aimco property debt $ 94,251 $ 83,587 Right of use lease assets 61,911 — Goodwill and other intangible assets, net 56,905 43,424 Notes receivable, net 41,300 39,254 Software, equipment and leasehold improvements 25,750 18,309 Accounts receivable, net 20,949 16,376 Prepaid expenses, real estate taxes and insurance 12,767 25,657 Investments in unconsolidated real estate partnerships 12,759 12,650 Deferred tax asset, net (Note 10) — 67,060 Deferred costs, deposits and other 24,880 45,224 Total other assets $ 351,472 $ 351,541
Goodwill and Other Intangible Assets, net	Goodwill and Other Intangible Assets, net As of December 31, 2019
Deferred Costs	Deferred Costs We defer, as debt issuance costs, lender fees and other direct costs incurred in obtaining new financing and amortize the amounts over the terms of the related loan agreements. In connection with the modification of existing financing arrangements, we defer lender fees and amortize these costs and any unamortized debt issuance costs over the term of the modified loan agreement. Debt issuance costs associated with our revolving credit facility are included in other assets in our consolidated balance sheets. Debt issuance costs associated with non-recourse property debt are presented as a direct deduction from the related liabilities in our consolidated balance sheets. When financing arrangements are repaid or otherwise extinguished prior to maturity, unamortized debt issuance costs are written off, additionally, any lender fees or other costs incurred in connection with the extinguishment are recognized as expense. Amortization and write-off of debt issuance costs and other extinguishment costs are included in interest expense in our consolidated statements of operations. We defer leasing costs incremental to a lease that we would not have incurred if the contract had not been obtained. Amortization of these costs is included in depreciation and amortization.
Revenue from Leases	Revenue from Leases We are a lessor primarily for residential leases. We also own approximately 1.1 million square feet of commercial space across our portfolio. In 2019 we adopted ASC 842, Leases Our operating leases with residents may also provide that the resident reimburse us for certain costs, primarily the resident’s share of utilities expenses, incurred by the apartment community. These reimbursements represent revenue attributable to nonlease components for which the timing and pattern of recognition is the same as the revenue for the lease components. We adopted the practical expedient that allows us to account for the lease and nonlease components as a single component. Reimbursement and related expense are presented on a gross basis in our consolidated statements of operations, with the reimbursement included in rental and other property revenues attributable to real estate in our consolidated statements of operations. We recognize rental revenue attributed to lease components, net of any concessions, on a straight-line basis over the term of the lease.
Asset Management Business	Asset Management Business Prior to the July 2018 sale of our Asset Management business, we provided asset management and other services to certain consolidated partnerships owning apartment communities that qualify for low-income housing tax credits and are structured to provide for the pass-through of tax credits and tax deductions to their partners. We consolidated those low-income housing tax credit partnerships in which we were the sole general partner and decision maker of the partnerships. We recognized income from asset management and other services when the related fees were earned and realized or realizable.
Depreciation and Amortization	Depreciation and Amortization Depreciation for all tangible assets is calculated using the straight-line method over their estimated useful lives. Acquired buildings and improvements are depreciated over a useful life based on the age, condition, and other physical characteristics of the asset. Furniture, fixtures, and equipment are generally depreciated over five years. We depreciate capitalized costs using the straight-line method over the estimated useful life of the related improvement, which is generally 5, 15, or 30 years. We also capitalize payroll and other indirect costs incurred in connection with preparing an asset for its intended used. These costs include corporate-level costs that clearly relate to the capital addition activities, which we allocate to the applicable assets. All capitalized payroll costs and indirect costs are allocated to capital additions proportionately based on direct costs and depreciated over the estimated useful lives of such capital additions. Purchased software and other costs related to software purchased or developed for internal use are capitalized during the application development stage and are amortized using the straight-line method over the estimated useful life of the software, generally three to five years. Purchased equipment is recognized at cost and depreciated using the straight-line method over the estimated useful life of the asset, which is generally five years. Leasehold improvements are also recorded at cost and depreciated on a straight-line basis over the shorter of the asset’s estimated useful life or the term of the related lease. Certain homogeneous items that are purchased in bulk on a recurring basis, such as appliances, are depreciated using group methods that reflect the average estimated useful life of the items in each group. Except in the case of apartment community casualties, where the net book value of the lost asset is written off in the determination of casualty gains or losses, we generally do not recognize any loss in connection with the replacement of an existing apartment community component because normal replacements are considered in determining the estimated useful lives used in connection with our composite and group depreciation methods.
Insurance	Insurance We believe our insurance coverages insure our apartment communities adequately against the risk of loss attributable to fire, earthquake, hurricane, tornado, flood, and other perils. In addition, we have third-party insurance coverage (after self-insured retentions) that defray the costs of large workers’ compensation, health, and general liability exposures. We accrue losses based upon our estimates of the aggregate liability for uninsured losses incurred using certain actuarial assumptions followed in the insurance industry and based on our experience.
Share-Based Compensation	Share-Based Compensation We issue various forms of share-based compensation, including stock options and restricted stock awards with service conditions and/or market conditions. We recognize share-based employee compensation based on the fair value on the grant date and recognize compensation cost over the awards’ requisite service periods. We reduce compensation cost related to forfeited awards in the period of forfeiture. Please refer to Note 9 for further discussion of our share-based compensation.
Income Taxes	Income Taxes Aimco has elected to be taxed as a REIT under the Internal Revenue Code commencing with its taxable year ended December 31, 1994, and it intends to continue to operate in such a manner. Aimco’s current and continuing qualification as a REIT depends on its ability to meet the various requirements imposed by the Internal Revenue Code, which are related to organizational structure, distribution levels, diversity of stock ownership and certain restrictions with regard to owned assets and categories of income. If Aimco qualifies for taxation as a REIT, it will generally not be subject to United States federal corporate income tax on its taxable income that is currently distributed to stockholders. This treatment substantially eliminates the “double taxation” (at the corporate and stockholder levels) that generally results from an investment in a corporation. Even if Aimco qualifies as a REIT, it may be subject to United States federal income and excise taxes in various situations, such as on undistributed income. Aimco also will be required to pay a 100% tax on any net income on non-arm’s length transactions between it and a TRS (described below) and on any net income from sales of apartment communities that were held for sale in the ordinary course. The state and local tax laws may not conform to the United States federal income tax treatment, and Aimco may be subject to state or local taxation in various state or local jurisdictions, including those in which we transact business. Any taxes imposed on us reduce our operating cash flow and net income. Certain of our operations or a portion thereof, including property management and risk management, are conducted through taxable REIT subsidiaries, which are subsidiaries of the Aimco Operating Partnership, and each of which we refer to as a TRS. A TRS is a subsidiary C-corporation that has not elected REIT status and , as such , is subject to United States federal corporate income tax. We use TRS entities to facilitate our ability to offer certain services and activities to our residents and investment partners that cannot be offered directly by a REIT. We also use TRS entities to hold investments in certain apartment communities. For our TRS entities, deferred income taxes result from temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for United States federal income tax purposes, and are measured using the enacted tax rates and laws that are expected to be in effect when the differences reverse. We reduce deferred tax assets by recording a valuation allowance when we determine, based on available evidence, that it is more likely than not that the assets will not be realized. We recognize the tax consequences associated with intercompany transfers between the Aimco Operating Partnership and TRS entities when such transactions occur. Please refer to Note 10 for further information about our income taxes.
Earnings Per Share and Unit	Earnings per Share and Unit Aimco and the Aimco Operating Partnership calculate earnings per share and unit based on the weighted-average number of shares of Common Stock or common partnership units, participating securities, common stock or common unit equivalents and dilutive convertible securities outstanding during the period. The Aimco Operating Partnership considers both common partnership units and equivalents, which have identical rights to distributions and undistributed earnings, to be common units for purposes of the earnings per unit computations. Please refer to Note 11 for further information regarding earnings per share and unit computations.
Use of Estimates	Use of Estimates The preparation of our consolidated financial statements in conformity with 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 On February 20, 2019, Aimco and the Aimco Operating Partnership effected a reverse split of Common Stock and common partnership units, respectively, at a ratio of one share or unit for every 1.03119 shares or units outstanding on the date of effectiveness. The accounting guidance for recapitalization events requires that we revise Aimco’s equity and the Aimco Operating Partnership’s partners’ capital as if the reverse split had occurred at the beginning of the earliest period presented. As such, we have revised the outstanding share and unit counts, presentation of share and unit activity, and earnings per share and unit, as if the reverse split had occurred on December 31, 2016.
Accounting Pronouncements Adopted in the Current Year	Accounting Pronouncements Adopted in the Current Year Effective January 1, 2019, we adopted ASC 842 issued by the Financial Accounting Standards Board, or FASB. We elected to adopt the new standard using practical expedients that do not require a look back to expired or existing contracts for embedded leases, allow us to retain the classification of existing leases, and allow us to retain the previous accounting for the initial direct costs of existing leases. As both a lessee and a lessor, we also elected to use the practical expedient that allows us to combine revenue attributable to nonlease components with associated lease components where the timing and pattern of transfer of the components are the same. Under the new standard, a contract is or contains a lease when it provides the right to control the use of an asset for a period of time in exchange for consideration. Lessor accounting remains largely unchanged other than how we recognize costs incurred to obtain leases. Under ASC 842, we defer leasing costs incremental to a lease that we would not have incurred if the contract had not been obtained. As a result of the practical expedient related to the combination of revenue from nonlease and lease components described above, we will combine rent payments with payments for other services we provide to our residents, including residents’ reimbursement of utility expenses. We have adopted the standard using the optional transition method that allows for prior reporting periods to remain as originally presented. Please refer to Note 4. In 2018, the Securities Exchange Commission, or SEC, amended its rules to eliminate, modify, or integrate into other SEC requirements certain disclosure rules. The amendments are intended to simplify compliance without significantly changing the total mix of information provided to investors. The amendments created a requirement to report dividends per share or unit and changes in equity in interim periods on a comparative basis for both quarter-to-date and year-to-date periods presented.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In 2016, the FASB issued ASC 326, Financial Instruments-Credit Losses financial instrument, including receivables, at its inception. Our notes receivable and AFS debt securities are subject to the new standard. For AFS debt securities, the new standard would require us to estimate a credit loss if the fair value of the instruments are less than their carrying value of the instruments . This credit loss standard is required to be applied using a modified-retrospective approach and requires a cumulative-effect adjustment to retained earnings be recorded as of the date of adoption. We adopted the new standard on January 1, 2020. The adoption of the standard is not expected to have a material impact on our financial position or results of operations.
Fair Value of Financial Instruments	Recurring Fair Value Measurements that holds certain of our property debt, which

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Other Assets	As of December 31, 2019 and 2018, other assets was comprised of the following amounts (in thousands): 2019 2018 Investments in securitization trust that holds Aimco property debt $ 94,251 $ 83,587 Right of use lease assets 61,911 — Goodwill and other intangible assets, net 56,905 43,424 Notes receivable, net 41,300 39,254 Software, equipment and leasehold improvements 25,750 18,309 Accounts receivable, net 20,949 16,376 Prepaid expenses, real estate taxes and insurance 12,767 25,657 Investments in unconsolidated real estate partnerships 12,759 12,650 Deferred tax asset, net (Note 10) — 67,060 Deferred costs, deposits and other 24,880 45,224 Total other assets $ 351,472 $ 351,541

Significant Transactions (Table

Significant Transactions (Tables)	12 Months Ended
	Dec. 31, 2019
Summary of Apartment Community Dispositions	During the years ended December 31, 2019, 2018, and 2017, we sold apartment communities as summarized below (dollars in thousands): 2019 2018 2017 Number of apartment communities sold 12 4 5 Number of apartment homes sold 3,596 1,334 2,291 Gain on dispositions of real estate (1) $ 503,168 $ 175,213 $ 297,730 (1) During the year ended December 31, 2019, gain on dispositions of real estate includes the expiration of indemnification liabilities related to the sale of our Asset Management business.
Asset Acquisitions
Summarized Information Regarding Acquisition	Summarized information regarding these acquisitions is set forth in the table below (in thousands): Purchase price $ 229,711 Capitalized transaction costs 4,057 Noncontrolling interests in consolidated real estate partnership 8,250 Total consideration (1) $ 242,018 Consideration allocated to building and improvements 218,752 Consideration allocated to land 162,094 Consideration allocated to intangible assets 16,500 Consideration allocated to intangible liabilities (6,519 ) Deferred tax liability assumed (2) (148,809 ) Total consideration $ 242,018 (1) Total consideration includes $97.6 million of debt assumed and issuance of 59,761 common OP Units. In accordance with GAAP, the common OP Units were valued at $50.77 per unit, the Aimco Common Stock closing price on the purchase date. (2) The deferred tax liability of $148.8 million resulted from the corporate structure used to complete the acquisition of 1001 Brickell Bay Drive and is due to the difference between the purchase price determined in accordance with GAAP and the tax basis of the property.

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lease Income for Operating Leases	Our total lease income was comprised of the following amounts for all operating leases for the year ended December 31, 2019 (in thousands): Fixed lease income $ 855,326 Variable lease income 56,424 Total lease income $ 911,750
Future Minimum Annual Rental Payments Receivable Under Residential and Commercial Leases	Future minimum annual rental payments we will receive under commercial leases, excluding such extension options, are as follows as of December 31, 2019 (in thousands): 2020 $ 26,770 2021 23,277 2022 19,766 2023 15,853 2024 13,512 Thereafter 52,040 Total $ 151,218
Minimum Annual Rental Payments Under these Operating Leases	Minimum annual rental payments under these operating leases, reconciled to the lease liability included in accrued liabilities and other in our consolidated balance sheets, are as follows (in thousands): Operating Lease Future Minimum Rent 2020 $ 5,156 2021 5,143 2022 5,053 2023 4,363 2024 4,392 Thereafter 427,935 Total $ 452,042 Less: Discount (394,735 ) Total lease liability $ 57,307

Non-Recourse Property Debt an_2

Non-Recourse Property Debt and Credit Agreement (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Summary of Non-Recourse Property Loans Payable Related to Properties Classified as Held for Use	The following table summarizes non-recourse property debt related to assets classified as held for use as of December 31, 2019 and 2018 (dollars in thousands): Latest Maturity Date Interest Rate Range Weighted-Average Interest Rate 2019 2018 Fixed-rate property debt January 1, 2055 2.73% to 6.79% 3.93% $ 4,081,221 $ 3,676,882 Variable-rate property debt July 13, 2033 2.51% to 3.00% 2.88% 170,118 260,118 Debt issuance costs, net of accumulated amortization (20,749) (21,695 ) Non-recourse property debt, net $ 4,230,590 $ 3,915,305
Scheduled Principal Amortization and Maturity Payments for Non-Recourse Property Debt	As of December 31, 2019, the scheduled principal amortization and maturity payments for the non-recourse property debt were as follows (in thousands): Amortization Maturities Total 2020 $ 92,177 $ 78,930 $ 171,107 2021 (1) 83,427 598,263 681,690 2022 78,909 260,671 339,580 2023 71,332 249,251 320,583 2024 67,561 285,517 353,078 Thereafter 391,512 1,993,789 2,385,301 Total $ 784,918 $ 3,466,421 $ 4,251,339 (1) Pursuant to the terms of our loan agreements, we may prepay in 2020 $246.5 million of loans maturing in 2021, without penalty.

Partners' Capital (Tables)

Partners' Capital (Tables)	12 Months Ended
	Dec. 31, 2019
Partners Capital [Abstract]
Classes of Preferred OP Units	As of December 31, 2019 and 2018, the Aimco Operating Partnership had the following classes of preferred OP Units (stated at their redemption values, in thousands, except unit and per unit data): Distributions per Annum Units Issued and Outstanding Redemption Values Class of Preferred Units Percent Per Unit 2019 2018 2019 2018 Class One 8.75 % $ 8.00 90,000 90,000 $ 8,229 $ 8,229 Class Two 1.92 % $ 0.48 11,122 14,240 278 356 Class Three 7.88 % $ 1.97 1,338,524 1,338,524 33,463 33,463 Class Four 8.00 % $ 2.00 644,954 644,954 16,124 16,124 Class Six 8.50 % $ 2.13 773,693 773,693 19,342 19,342 Class Seven 7.87 % $ 1.97 26,150 27,960 654 699 Class Nine 6.00 % $ 1.50 78,956 243,112 1,974 6,078 Class Ten 6.00 % $ 1.50 680,000 680,000 17,000 17,000 Total 3,643,399 3,812,483 $ 97,064 $ 101,291
Reconciliation of Preferred OP Units	The following table presents a reconciliation of the Aimco Operating Partnership’s preferred OP Units during the year ended December 31, 2019 (in thousands): 2019 Balance at January 1 $ 101,291 Preferred distributions (7,708 ) Redemption of preferred units (4,227 ) Net income 7,708 Balance at December 31 $ 97,064

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Summary of Total Compensation Cost Recognized for Share-Based Awards	Total compensation cost recognized for share-based awards was as follows for the years ended December 31, 2019, 2018, and 2017 (in thousands): 2019 2018 2017 Share-based compensation expense (1) $ 8,146 $ 8,550 $ 7,877 Capitalized share-based compensation (2) 962 1,215 1,374 Total share-based compensation (3) $ 9,108 $ 9,765 $ 9,251 (1) Amounts are recorded in general and administrative expenses on the consolidated statements of operations. (2) Amounts are recorded in building and improvements on the consolidated balance sheets. (3) Amounts are recorded in additional paid-in capital and common noncontrolling interests in the Aimco Operating Partnership on the Aimco consolidated balance sheets, and in general partner and special limited partner and limited partners on the Aimco Operating Partnership consolidated balance sheets.
Summary of Activity for Outstanding Stock Options	The following table summarizes activity for our outstanding stock options, for the years ended December 31, 2019, 2018, and 2017 (options in thousands): 2019 2018 2017 Number of Options Weighted-Average Exercise Price Number of Options Weighted-Average Exercise Price Number of Options Weighted-Average Exercise Price Outstanding at beginning of year 646 $ 40.12 648 $ 40.08 675 $ 29.55 Granted — — — — 184 44.07 Exercised (5 ) 8.92 (2 ) 28.33 (211 ) 9.90 Forfeited — — — — — — Outstanding at end of year 641 $ 40.30 646 $ 40.12 648 $ 40.08 Exercisable at end of year 458 $ 38.78 186 $ 38.18 128 $ 37.59
Summary of Activity for Restricted Stock Awards	The following table summarizes activity for Time-Based Restricted Stock awards for the years ended December 31, 2019, 2018, and 2017 (shares in thousands): 2019 2018 2017 Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Unvested at beginning of year 121 $ 40.82 155 $ 37.63 241 $ 33.61 Granted 48 47.71 49 40.01 44 44.07 Vested (75 ) 42.76 (83 ) 34.42 (130 ) 32.35 Forfeited (2 ) 38.80 — — — — Unvested at end of year 92 $ 42.86 121 $ 40.82 155 $ 37.63 The following table summarizes activity for TSR Restricted Stock awards for the years ended December 31, 2019, 2018, and 2017 (shares in thousands): 2019 2018 2017 Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Number of Shares Weighted-Average Grant-Date Fair Value Unvested at beginning of year 171 $ 41.65 246 $ 40.70 208 $ 39.66 Granted (1) 39 54.73 44 41.71 38 46.39 Change in awards (2) 216 39.67 — — — — Vested (213 ) 39.67 (119 ) 39.72 — — Unvested at end of year 213 $ 43.99 171 $ 41.65 246 $ 40.70 (1) Based on target performance payout. (2) Represents the change in the number of restricted stock awards earned at the end of the measurement period.
Summary of Activity for TSR LTIP I Units and TSR LTIP II Units	The following table summarizes activity for TSR LTIP I units for the years ended December 31, 2019, 2018, and 2017 (units in thousands): 2019 2018 2017 Number of Units Weighted-Average Grant-Date Fair Value Number of Units Weighted-Average Grant-Date Fair Value Number of Units Weighted-Average Grant-Date Fair Value Unvested at beginning of year 93 $ 43.78 45 $ 46.21 — $ — Granted 6 55.17 48 41.48 45 46.21 Unvested at end of year 99 $ 44.38 93 $ 43.78 45 $ 46.21 The following table summarizes activity for TSR LTIP II units for the years ended December 31, 2019 and 2018 (units in thousands): 2019 2018 Number of Units Weighted-Average Grant-Date Fair Value Number of Units Weighted-Average Grant-Date Fair Value Unvested at beginning of year 243 $ 8.29 — $ — Granted 356 12.03 243 8.29 Unvested at end of year 599 $ 10.51 243 $ 8.29
Assumptions Used in Determination of Grant-Date Fair Value of Awards	The valuation assumptions for the 2019, 2018, and 2017 grants were as follows: 2019 2018 2017 Grant date market value of a common share $ 49.24 $ 40.95 $ 44.07 Risk-free interest rate 2.59% - 2.66 % 2.32% - 2.68 % 1.57% - 2.22 % Dividend yield 3.09 % 3.52 % 3.27 % Expected volatility 19.08% - 19.24 % 17.64% - 18.02 % 21.33% - 23.00 % Derived vesting period of TSR Restricted Stock and TSR LTIP I units 3.4 years 3.4 years 3.4 years Weighted average expected term of TSR Stock Options and LTIP II units 5.8 years 5.6 years 5.8 years

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Components of Deferred tax Liabilities and Assets	Significant components of our deferred tax liabilities and assets are as follows (in thousands): December 31, 2019 2018 Deferred tax liabilities: Real estate and real estate partnership basis differences $ 126,269 $ 12,058 Deferred tax assets: Tax credit carryforwards $ 53,776 $ 67,530 Net operating, capital and other loss carryforwards 6,147 7,022 Accruals and expenses 6,138 7,432 Management contracts and other 1,379 2,064 Total deferred tax assets 67,440 84,048 Valuation allowance (4,766 ) (4,930 ) Net deferred tax (liabilities) assets $ (63,595 ) $ 67,060
Reconciliation of Unrecognized Tax Benefits	A reconciliation of the beginning and ending balance of our unrecognized tax benefits is presented below (in thousands): 2019 2018 2017 Balance at January 1 $ 2,618 $ 2,476 $ 2,286 Additions based on tax position taken in current year 2,758 — — Additions based on tax positions related to prior years 226 142 190 Reductions as a result of a lapse of the applicable statutes (522 ) — — Balance at December 31 $ 5,080 $ 2,618 $ 2,476
Components of Income Tax Benefit or Expense	Significant components of the income tax benefit or expense are as follows and are classified within income tax benefit in our consolidated statements of operations for the years ended December 31, 2019, 2018, and 2017 (in thousands): 2019 2018 2017 Current: Federal $ 6,115 $ 11,269 $ (938 ) State 8,982 10,537 525 Total current 15,097 21,806 (413 ) Deferred: Federal (12,891 ) (29,243 ) (10,908 ) State (5,341 ) (5,590 ) (3,621 ) Revaluation of deferred taxes due to change in tax rate — — (15,894 ) Total deferred (18,232 ) (34,833 ) (30,423 ) Total benefit $ (3,135 ) $ (13,027 ) $ (30,836 )
Reconciliation of Income Tax Attributable to Operations	The reconciliation of income tax attributable to operations computed at the United States statutory rate to income tax benefit is shown below (dollars in thousands): 2019 2018 2017 Amount Percent Amount Percent Amount Percent Tax (benefit) provision at United States statutory rates on consolidated income or loss subject to tax $ (4,442 ) 21.0 % $ 33,296 21.0 % $ (19,459 ) 35.0 % United States branch profits tax on losses of a foreign subsidiary (1,813 ) 8.6 % — — % — — % State income tax expense, net of federal tax (benefit) expense 3,935 (18.6 %) 12,252 7.7 % (1,769 ) 3.2 % Establishment of deferred tax asset related to partnership basis difference (1) — — % — — % (3,501 ) 6.3 % Effect of permanent differences (138 ) 0.7 % 302 0.2 % (1,629 ) 2.9 % Tax effect of intercompany transactions (2) — — % (33,250 ) (21.0 %) — — % Tax credits (667 ) 3.2 % (6,897 ) (4.4 %) (9,607 ) 17.3 % Tax reform revaluation (3) — — % 288 0.2 % (15,894 ) 28.6 % (Decrease) increase in valuation allowance (4) (164 ) 0.8 % (20,434 ) (12.9 %) 21,023 (37.8 %) Other 154 (0.7 %) 1,416 0.9 % — — % Total income tax benefit $ (3,135 ) 15.0 % $ (13,027 ) (8.3 %) $ (30,836 ) 55.5 % (1) 2017 includes the establishment of a deferred tax asset related to partnership basis difference when it became apparent that it would reverse in the foreseeable future. This deferred tax asset was fully reserved in the valuation allowance described below as of December 31, 2017. (2) Effective January 1, 2017, we adopted a new accounting standard applicable to intercompany asset transfers. As a result, the accumulated unrecognized deferred tax expense associated with historical intercompany transfers was recognized as a cumulative effect adjustment through retained earnings at that time. 2018 includes the tax benefit to establish the initial deferred tax asset from the intercompany transfer of a portion of the Asset Management business between the Aimco Operating Partnership and TRS entities. (3) Reflects revaluation of deferred tax assets and liabilities using the TRS entities’ lower effective tax rates resulting from the 2017 Act. Accounting for the tax effects of enactment of the 2017 Act was finalized during the year ended December 31, 2018. (4) 2019 includes a $0.2 million release of a valuation allowance for expired state NOL carryforwards. 2017 includes a $15.4 million valuation allowance against the deferred tax assets associated with rehabilitation tax credits due to the lower federal tax rate under the 2017 Act. This valuation allowance was reversed in 2018 as a result of the sale of our Asset Management business.
Schedule of Dividends Per Share Held	For the years ended December 31, 2019 , 2018 , and 2017 , dividends per share held for the entire year were estimated to be taxable as follows: 2019 2018 2017 Amount Percentage Amount Percentage Amount Percentage Ordinary income $ 0.66 20.7 % $ 0.51 33.4 % $ 0.75 51.5 % Capital gains 1.29 40.4 % 0.93 61.2 % 0.51 35.7 % Qualified dividends 0.66 20.7 % — — % 0.02 1.6 % Unrecaptured Section 1250 gain 0.58 18.2 % 0.08 5.4 % 0.16 11.2 % Total $ 3.19 100.0 % $ 1.52 100.0 % $ 1.44 100.0 %

Earnings per Share and per Un_2

Earnings per Share and per Unit (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Reconciliations of Numerator and Denominator in Calculations of Basic and Diluted Earnings per Share and per Unit	Reconciliations of the numerator and denominator in the calculations of basic and diluted earnings per share and per unit for the years ended December 31, 2019, 2018, and 2017 are as follows (in thousands, except per share and per unit data): 2019 2018 2017 Earnings per share Numerator: Basic and dilutive net income attributable to Aimco common stockholders $ 466,144 $ 656,597 $ 306,861 Denominator - shares: Basic weighted-average Common Stock outstanding 147,718 151,152 151,595 Dilutive share equivalents outstanding 226 182 465 Dilutive weighted-average Common Stock outstanding 147,944 151,334 152,060 Earnings per share – basic $ 3.16 $ 4.34 $ 2.02 Earnings per share – dilutive $ 3.15 $ 4.34 $ 2.02 Non-dilutive share equivalents outstanding — 269 184 Earnings per unit Numerator: Basic and dilutive net income attributable to the Aimco Operating Partnership's common unitholders $ 492,177 $ 690,874 $ 321,300 Denominator - units Basic weighted-average common partnership units outstanding 155,882 158,890 158,793 Dilutive partnership unit equivalents outstanding 335 183 464 Dilutive weighted-average common partnership units outstanding 156,217 159,073 159,257 Earnings per unit – basic $ 3.16 $ 4.35 $ 2.02 Earnings per unit – dilutive $ 3.15 $ 4.34 $ 2.02 Non-dilutive partnership unit equivalents outstanding — 269 184

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Summary of Fair Value for AFS Debt Securities	The following table summarizes fair value for our AFS debt securities as of December 31, 2019 and 2018 (in thousands): As of December 31, 2019 2018 Total Fair Value Level 1 Level 2 Level 3 Total Fair Value Level 1 Level 2 Level 3 AFS debt securities $ 94,251 $ — $ 94,251 $ — $ 88,457 $ — $ 88,457 $ —
Summary of Carrying Value and Fair Value of Non-recourse Property Debt	The following table summarizes carrying value and fair value of our non-recourse property debt as of December 31, 2019 and 2018 (in thousands): As of December 31, 2019 2018 Carrying Value Fair Value Carrying Value Fair Value Non-recourse property debt $ 4,251,339 $ 4,298,630 $ 3,937,000 $ 3,893,171

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2019
Segment Reporting [Abstract]
Summary of Information for Reportable Segments	The following tables present the revenues, proportionate property net operating income and income before income tax benefit of our segments on a proportionate basis and excluding our proportionate share of four apartment communities with 142 apartment homes that we neither manage nor consolidate, and amounts related to communities sold as of December 31, 2019 for the years ended December 31, 2019, 2018, and 2017 (in thousands): Same Store Redevelopment and Development Acquisition Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Year ended December 31, 2019: Total revenues $ 691,379 $ 75,522 $ 42,038 $ 45,105 $ 33,450 $ 26,800 $ 914,294 Property operating expenses attributable to real estate 181,802 27,919 11,715 17,717 31,140 40,928 311,221 Other operating expenses not allocated to segments (3) — — — — — 446,300 446,300 Total operating expenses 181,802 27,919 11,715 17,717 31,140 487,228 757,521 Proportionate property net operating income 509,577 47,603 30,323 27,388 2,310 (460,428 ) 156,773 Other items included in income before income tax benefit (4) — — — — — 348,119 348,119 Income before income tax benefit $ 509,577 $ 47,603 $ 30,323 $ 27,388 $ 2,310 $ (112,309 ) $ 504,892 Same Store Redevelopment and Development Acquisition Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Year ended December 31, 2018: Total revenues $ 665,835 $ 76,687 $ 27,923 $ 37,647 $ 31,442 $ 132,876 $ 972,410 Property operating expenses attributable to real estate 177,466 27,836 7,689 14,910 29,323 50,677 307,901 Other operating expenses not allocated to segments (3) — — — — — 448,753 448,753 Total operating expenses 177,466 27,836 7,689 14,910 29,323 499,430 756,654 Proportionate property net operating income 488,369 48,851 20,234 22,737 2,119 (366,554 ) 215,756 Other items included in income before income tax benefit (4) — — — — — 487,820 487,820 Income before income tax benefit $ 488,369 $ 48,851 $ 20,234 $ 22,737 $ 2,119 $ 121,266 $ 703,576 Same Store Redevelopment and Development Acquisition Other Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Segments (2) Consolidated Year ended December 31, 2017: Total revenues $ 626,311 $ 72,995 $ — $ 36,869 $ 39,776 $ 229,486 $ 1,005,437 Property operating expenses attributable to real estate 171,167 26,471 — 14,121 29,782 77,585 319,126 Other operating expenses not allocated to segments (3) — — — — — 492,328 492,328 Total operating expenses 171,167 26,471 — 14,121 29,782 569,913 811,454 Proportionate property net operating income 455,144 46,524 — 22,748 9,994 (340,427 ) 193,983 Other items included in income before income tax benefit (4) — — — — — 122,260 122,260 Income before income tax benefit $ 455,144 $ 46,524 $ — $ 22,748 $ 9,994 $ (218,167 ) $ 316,243 (1) Represents adjustments for the noncontrolling interests in consolidated real estate partnerships’ share of the results of consolidated apartment 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 attributable to real estate in our 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, and the operating results of communities owned by consolidated partnerships served by our Asset Management business prior to its sale in July 2018. Corporate and Amounts Not Allocated to Segments 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. (3) Other operating expenses not allocated to segments consists of property operating expenses of partnerships served by our Asset Management business prior to its sale in July 2018, depreciation and amortization, general and administrative expenses and other operating expenses including provision for real estate impairment loss, which are not included in our measure of segment performance. (4) Other items included in income before income tax benefit primarily consists of gain on dispositions of real estate and the Asset Management business 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): December 31, 2019 December 31, 2018 Same Store $ 3,982,586 $ 4,068,880 Redevelopment and Development 946,390 792,126 Acquisition 623,037 507,190 Other Real Estate 647,725 327,092 Corporate and other assets (1) 629,001 494,716 Total consolidated assets $ 6,828,739 $ 6,190,004 (1) Includes the assets not allocated to our segments, primarily corporate assets, assets of apartment communities which were sold or classified as held for sale as of December 31, 2019, and the Asset Management business.
Capital Additions Related to Segments	For the years ended December 31, 2019, 2018, and 2017, capital additions related to our segments were as follows (in thousands): 2019 2018 2017 Same Store $ 153,944 $ 171,869 $ 215,130 Redevelopment and Development 194,498 138,103 84,712 Acquisition 33,122 14,228 — Other Real Estate 20,011 6,314 12,044 Total capital additions $ 401,575 $ 330,514 $ 311,886

Unaudited Summarized Consolid_2

Unaudited Summarized Consolidated Quarterly Information (Tables)	12 Months Ended
	Dec. 31, 2019
Schedule of Unaudited Quarterly Financial Information [Line Items]
Summarized Unaudited Consolidated Quarterly Information	Aimco’s summarized unaudited consolidated quarterly information for the years ended December 31, 2019 and 2018, is provided below (in thousands, except per share amounts): Quarter 2019 First Second Third Fourth Total revenues $ 230,235 $ 224,200 $ 229,827 $ 230,032 Net income 291,295 69,996 3,970 142,766 Net income attributable to Aimco common stockholders 271,568 59,234 2,003 133,339 Net income attributable to Aimco common stockholders per common share – basic $ 1.88 $ 0.40 $ 0.01 $ 0.90 Net income attributable to Aimco common stockholders per common share – diluted $ 1.88 $ 0.40 $ 0.01 $ 0.90 Quarter 2018 First Second Third Fourth Total revenues $ 247,720 $ 250,187 $ 242,481 $ 232,022 Net income 95,690 7,156 603,917 9,840 Net income attributable to Aimco common stockholders 81,525 2,817 567,029 5,226 Net income attributable to Aimco common stockholders per common share – basic $ 0.54 $ 0.02 $ 3.73 $ 0.04 Net income attributable to Aimco common stockholders per common share – diluted $ 0.54 $ 0.02 $ 3.73 $ 0.04
AIMCO PROPERTIES, L.P. [Member]
Schedule of Unaudited Quarterly Financial Information [Line Items]
Summarized Unaudited Consolidated Quarterly Information	The Aimco Operating Partnership’s summarized unaudited consolidated quarterly information for the years ended December 31, 2019 and 2018, is provided below (in thousands, except per unit amounts): Quarter 2019 First Second Third Fourth Total revenues $ 230,235 $ 224,200 $ 229,827 $ 230,032 Net income 291,295 69,996 3,970 142,766 Net income attributable to the Partnership’s common unitholders 286,639 62,817 2,138 140,583 Net income attributable to the Partnership’s common unitholders per common unit – basic $ 1.88 $ 0.40 $ 0.01 $ 0.90 Net income attributable to the Partnership’s common unitholders per common unit – diluted $ 1.88 $ 0.40 $ 0.01 $ 0.90 Quarter 2018 First Second Third Fourth Total revenues $ 247,720 $ 250,187 $ 242,481 $ 232,022 Net income 95,690 7,156 603,917 9,840 Net income attributable to the Partnership’s common unitholders 85,274 2,949 597,100 5,551 Net income attributable to the Partnership’s common unitholders per common unit – basic $ 0.54 $ 0.02 $ 3.73 $ 0.04 Net income attributable to the Partnership’s common unitholders per common unit – diluted $ 0.54 $ 0.02 $ 3.72 $ 0.04

Organization (Details Textual)

Organization (Details Textual)	12 Months Ended
	Dec. 31, 2019Propertyapartment_homeshares
Partially Owned Properties [Member]
Organization [Line Items]
Number of apartment communities | Property	124
Number of apartment homes in apartment communities | apartment_home	32,839
Percentage of average ownership of portfolio	99.00%
Wholly And Partially Owned Consolidated Properties [Member]
Organization [Line Items]
Number of apartment communities | Property	120
Number of apartment homes in apartment communities | apartment_home	32,697
AIMCO PROPERTIES, L.P [Member]
Organization [Line Items]
Common operating partnership units and equivalents outstanding | shares	158,419,051
Common operating partnership units and equivalents outstanding | shares	148,885,197
Percentage of the Aimco Operating Partnership's common partnership units and equivalents owned by Aimco	94.00%

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies (Details Textual) $ in Millions	Feb. 20, 2019	Feb. 03, 2019	Dec. 31, 2019USD ($)ft²Entity	Dec. 31, 2018USD ($)Entity	Dec. 31, 2017USD ($)
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Weighted average ownership interest			6.00%	4.90%	4.50%
Interest costs capitalized			$ 11.8	$ 7.6	$ 7.6
Other direct and indirect costs capitalized			37.8	36.8	$ 36
Goodwill			$ 37.8	$ 37.8
Estimated useful life			15 years
Percentage of income tax on income from non-arms length transactions			100.00%
Equity reverse stock split	0.0103119	0.0103119
Minimum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life			5 years
Estimated useful life of software			3 years
Maximum [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life			30 years
Estimated useful life of software			5 years
Commercial lease [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Area of commercial space | ft²			1,100,000
Furniture, Fixtures and Equipment [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life			5 years
Equipment [Member]
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Estimated useful life			5 years
Variable Interest Entity, Primary Beneficiary
Basis Of Presentation And Summary Of Significant Accounting Policies [Line Items]
Number of consolidated variable interest entities | Entity			6	9

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Summary of Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Asset Reconciling Item [Line Items]
Investments in securitization trust that holds Aimco property debt	$ 94,251	$ 83,587
Right of use lease assets	61,911
Goodwill and other intangible assets, net	56,905	43,424
Notes receivable, net	41,300	39,254
Software, equipment and leasehold improvements	25,750	18,309
Accounts receivable, net	20,949	16,376
Prepaid expenses, real estate taxes and insurance	12,767	25,657
Investments in unconsolidated real estate partnerships	280,258	0
Deferred tax asset, net (Note 10)		67,060
Deferred costs, deposits and other	24,880	45,224
Total other assets	351,472	351,541
Unconsolidated Real Estate Partnerships [Member]
Segment Reporting Asset Reconciling Item [Line Items]
Investments in unconsolidated real estate partnerships	$ 12,759	$ 12,650

Significant Transactions (Detai

Significant Transactions (Details Textual) $ in Thousands	Nov. 26, 2019USD ($)aapartment_home	Dec. 31, 2019USD ($)aPropertyapartment_homeCommunity	Dec. 31, 2018USD ($)Propertyapartment_home	Dec. 31, 2017USD ($)Propertyapartment_home
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on dispositions of real estate and the Asset Management business		$ 503,168	$ 677,463	$ 300,849
Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment communities sold | Community		0
1001 Brickell Bay Drive [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Area of land | a		1.8
Business acquisition, percentage of interest acquired		95.00%
Business acquisition, percentage of remaining interest acquired		5.00%
Business acquisition, exercise period		3 months
Business acquisition, effective date		Jul. 2, 2022
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 homes | apartment_home		32,697
Number of apartment communities sold | Property		120
Wholly And Partially Owned Consolidated Properties [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment homes | apartment_home		3,596	1,334	2,291
Gross proceeds from the sale of real estate			$ 590,000
Gain on dispositions of real estate and the Asset Management business		$ 503,168	175,213	$ 297,730
Net proceeds to Aimco from the sale of real estate			$ 512,200
Number of apartment communities sold | Property		12	4	5
Wholly And Partially Owned Consolidated Properties [Member] | Asset Management Business [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on dispositions of real estate and the Asset Management business			$ 500,300
Wholly And Partially Owned Consolidated Properties [Member] | La Jolla Cove [Member] | Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Stated value of seller financing provided			48,600
Net cash proceeds received			$ 5,000
Parkmerced Investment [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [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
Equity method investment, percentage of interest acquired	30.00%
Equity method investment, option term	10 years
Equity method investment, exercise price	$ 1,000
Equity method investment, increase future capital percentage	30.00%
Area of land | a	152
Parkmerced Investment [Member] | Rent-control Apartment Homes [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment homes | apartment_home	3,221
Parkmerced Investment [Member] | New Market-rate Homes [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment homes | apartment_home	4,093

Significant Transactions - Summ

Significant Transactions - Summarized Information Regarding Acquisition (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Noncontrolling interests in consolidated real estate partnerships	$ (3,296)	$ (2,967)
Consideration allocated to building and improvements	6,868,543	6,552,065
Consideration allocated to land	1,869,048	$ 1,756,525
Asset Acquisitions
Business Acquisition [Line Items]
Purchase price	229,711
Capitalized transaction costs	4,057
Noncontrolling interests in consolidated real estate partnerships	8,250
Total consideration	242,018
Consideration allocated to building and improvements	218,752
Consideration allocated to land	162,094
Consideration allocated to intangible assets	16,500
Consideration allocated to intangible liabilities	(6,519)
Deferred tax liability assumed	$ (148,809)

Significant Transactions - Su_2

Significant Transactions - Summarized Information Regarding Acquisition (Parenthetical) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)$ / sharesshares
Business Acquisition [Line Items]
Deferred tax liabilities	$ 63,595
Asset Acquisitions
Business Acquisition [Line Items]
Assumed debt	$ 97,600
Issuance of common OP Units | shares	59,761
Share price per unit (in dollars per share) | $ / shares	$ 50.77
1001 Brickell Bay Drive [Member]
Business Acquisition [Line Items]
Deferred tax liabilities	$ 148,800

Significant Transactions - Su_3

Significant Transactions - Summary of Apartment Community Dispositions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Propertyapartment_home	Dec. 31, 2018USD ($)Propertyapartment_home	Dec. 31, 2017USD ($)Propertyapartment_home
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on dispositions of real estate | $	$ 503,168	$ 677,463	$ 300,849
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	120
Number of apartment homes | apartment_home	32,697
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	12	4	5
Number of apartment homes | apartment_home	3,596	1,334	2,291
Gain on dispositions of real estate | $	$ 503,168	$ 175,213	$ 297,730

Leases - Lease Income for Opera

Leases - Lease Income for Operating Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Leases [Abstract]
Fixed lease income	$ 855,326
Variable lease income	56,424
Total lease income	$ 911,750

Leases - Future Minimum Annual

Leases - Future Minimum Annual Payments Receivable Under Residential and Commercial Leases (Details) - Commercial Real Estate [Member] $ in Thousands	Dec. 31, 2019USD ($)
Lessee Lease Description [Line Items]
2020	$ 26,770
2021	23,277
2022	19,766
2023	15,853
2024	13,512
Thereafter	52,040
Total	$ 151,218

Leases (Details Textual)

Leases (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Total lease liability	$ 57,307
Commercial lease [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Lease, existence of option to extend	true
Residential Lease [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Lease, existence of option to extend	false
Weighted average remaining term	8 months 24 days
Lease, option to extend	Generally, our residential leases do not provide extension options
Ground and Office Leases [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Lease cost	$ 10,700
Lease cost		$ 5,100	$ 4,800
Ground Lease [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Weighted average remaining term	74 years
Operating lease, weighted average discount rate, percent	6.55%
Total lease liability	$ 43,700
Office Lease [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Weighted average remaining term	8 years 4 months 24 days
Operating lease, weighted average discount rate, percent	3.22%

Leases - Minimum Annual Rental

Leases - Minimum Annual Rental Payments Under these Operating Leases (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 5,156
2021	5,143
2022	5,053
2023	4,363
2024	4,392
Thereafter	427,935
Total	452,042
Less: Discount	(394,735)
Total lease liability	$ 57,307
Operating Lease, Liability, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesAndOtherLiabilities

Non-Recourse Property Debt an_3

Non-Recourse Property Debt and Credit Agreement - Summary of Non-Recourse Property Loans Payable Related to Properties Classified as Held for Use (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Non-recourse property debt, net	$ 4,230,590	$ 3,915,305
Debt issuance costs, net of accumulated amortization	(20,749)	(21,695)
Fixed-rate property debt
Debt Instrument [Line Items]
Non-recourse property debt, net	$ 4,081,221	3,676,882
Weighted-Average Interest Rate	3.93%
Fixed-rate property debt | Maximum [Member]
Debt Instrument [Line Items]
Latest Maturity Date	Jan. 1, 2055
Interest Rate	6.79%
Fixed-rate property debt | Minimum [Member]
Debt Instrument [Line Items]
Interest Rate	2.73%
Variable-rate property debt
Debt Instrument [Line Items]
Non-recourse property debt, net	$ 170,118	$ 260,118
Weighted-Average Interest Rate	2.88%
Variable-rate property debt | Maximum [Member]
Debt Instrument [Line Items]
Latest Maturity Date	Jul. 13, 2033
Interest Rate	3.00%
Variable-rate property debt | Minimum [Member]
Debt Instrument [Line Items]
Interest Rate	2.51%

Non-Recourse Property Debt an_4

Non-Recourse Property Debt and Credit Agreement (Details Textual) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Property	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Outstanding borrowings under the revolving credit facility	$ 275,000	$ 160,360
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Revolving loan commitments	800,000
Outstanding borrowings under the revolving credit facility	$ 275,000	$ 160,400
Credit facility interest rate at period end	3.00%	3.93%
Amount outstanding for undrawn letters of credit issued under revolving credit facility	$ 7,200
Remaining borrowing capacity under credit facility	$ 517,800
Initial interest rate for credit facility	LIBOR plus 1.20%, or, at our option, a base rate plus 0.20%
Spread on variable interest rate	0.20%
Credit facility maturity date	Jan. 22, 2022
Credit facility, dividend restrictions	aggregate amount that does not exceed the greater of 95% of our funds from operations, as defined by Nareit, for such period, subject to certain non-cash adjustments, or such amount as may be necessary to maintain Aimco’s REIT
Revolving Credit Facility [Member] | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Spread on variable interest rate	1.20%
Fixed Rate Property Debt
Debt Instrument [Line Items]
Aggregate gross book value	$ 4,300,000
Fixed Rate Property Debt | Pledged as Collateral
Debt Instrument [Line Items]
Number of apartment communities | Property	78
Variable-rate property debt
Debt Instrument [Line Items]
Aggregate gross book value	$ 105,700
Variable-rate property debt | Pledged as Collateral
Debt Instrument [Line Items]
Number of apartment communities | Property	7

Non-Recourse Property Debt an_5

Non-Recourse Property Debt and Credit Agreement - Scheduled Principal Amortization and Maturity Payments for Non-Recourse Property Debt (Details) $ in Thousands	Dec. 31, 2019USD ($)
Amortization
2020	$ 92,177
2021	83,427
2022	78,909
2023	71,332
2024	67,561
Thereafter	391,512
Total	784,918
Maturities
2020	78,930
2021	598,263
2022	260,671
2023	249,251
2024	285,517
Thereafter	1,993,789
Total	3,466,421
Long Term Debt Amortization and Maturities
2020	171,107
2021	681,690
2022	339,580
2023	320,583
2024	353,078
Thereafter	2,385,301
Total	$ 4,251,339

Non-Recourse Property Debt an_6

Non-Recourse Property Debt and Credit Agreement - Scheduled Principal Amortization and Maturity Payments for Non-Recourse Property Debt (Parenthetical) (Details) $ in Millions	Dec. 31, 2019USD ($)
Debt Disclosure [Abstract]
Loans maturing in 2021 that may be prepaid without penalty	$ 246.5

Commitments and Contingencies (

Commitments and Contingencies (Details Textual) $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2017Party	Dec. 31, 2019USD ($)
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 active redevelopments and developments | $		$ 254.5
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

Aimco Equity (Details Textual)

Aimco Equity (Details Textual) $ / shares in Units, $ in Millions	Feb. 24, 2020shares	Feb. 20, 2019	Feb. 03, 2019USD ($)shares	Dec. 31, 2019$ / sharesshares	Dec. 31, 2018$ / sharesshares	Dec. 31, 2017$ / shares	Feb. 23, 2020shares
Classes of perpetual preferred stock
Dividends declared per common share (in dollars per share)				$ 3.19	$ 1.52	$ 1.44
Equity reverse stock split		0.0103119	0.0103119
Quarterly cash dividend amount (in dollars per share)				$ 0.39
Common Stock, shares authorized (in shares) | shares				500,787,260	500,787,260
Subsequent Event [Member]
Classes of perpetual preferred stock
Common Stock, shares authorized (in shares) | shares	510,587,500						500,787,260
Common Stock, increase in number of shares authorized (in shares) | shares	9,800,240
Cash Dividend Excluding Special Dividend [Member]
Classes of perpetual preferred stock
Dividends declared per common share (in dollars per share)				$ 1.56
Special Dividend Paid [Member]
Classes of perpetual preferred stock
Cash dividends on common stock declared | $			$ 67.1
Common shares issued in special dividend (in shares) | shares			4,500,000
Special dividend, cash paid in lieu of fractional shares | $			$ 0.4
Class A Cumulative Preferred Stock [Member]
Classes of perpetual preferred stock
Preferred stock, redeemed outstanding shares, percentage				6.88%
Per share par value of preferred stock issued (in dollars per share)				$ 0.01
Preferred stock, liquidation preference per share (in dollars per share)				$ 25

Partners' Capital - Classes of

Partners' Capital - Classes of Preferred OP Units (Details) - AIMCO PROPERTIES, L.P. [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Limited Partners Capital Account [Line Items]
Units issued (in shares)	3,643,399	3,812,483
Units outstanding (in shares)	3,643,399	3,812,483
Redemption values	$ 97,064	$ 101,291
Class One [Member]
Limited Partners Capital Account [Line Items]
Distributions per annum	8.75%
Distributions per annum (in dollars per share)	$ 8
Units issued (in shares)	90,000	90,000
Units outstanding (in shares)	90,000	90,000
Redemption values	$ 8,229	$ 8,229
Class Two [Member]
Limited Partners Capital Account [Line Items]
Distributions per annum	1.92%
Distributions per annum (in dollars per share)	$ 0.48
Units issued (in shares)	11,122	14,240
Units outstanding (in shares)	11,122	14,240
Redemption values	$ 278	$ 356
Class Three [Member]
Limited Partners Capital Account [Line Items]
Distributions per annum	7.88%
Distributions per annum (in dollars per share)	$ 1.97
Units issued (in shares)	1,338,524	1,338,524
Units outstanding (in shares)	1,338,524	1,338,524
Redemption values	$ 33,463	$ 33,463
Class Four [Member]
Limited Partners Capital Account [Line Items]
Distributions per annum	8.00%
Distributions per annum (in dollars per share)	$ 2
Units issued (in shares)	644,954	644,954
Units outstanding (in shares)	644,954	644,954
Redemption values	$ 16,124	$ 16,124
Class Six [Member]
Limited Partners Capital Account [Line Items]
Distributions per annum	8.50%
Distributions per annum (in dollars per share)	$ 2.13
Units issued (in shares)	773,693	773,693
Units outstanding (in shares)	773,693	773,693
Redemption values	$ 19,342	$ 19,342
Class Seven [Member]
Limited Partners Capital Account [Line Items]
Distributions per annum	7.87%
Distributions per annum (in dollars per share)	$ 1.97
Units issued (in shares)	26,150	27,960
Units outstanding (in shares)	26,150	27,960
Redemption values	$ 654	$ 699
Class Nine [Member]
Limited Partners Capital Account [Line Items]
Distributions per annum	6.00%
Distributions per annum (in dollars per share)	$ 1.50
Units issued (in shares)	78,956	243,112
Units outstanding (in shares)	78,956	243,112
Redemption values	$ 1,974	$ 6,078
Class Ten [Member]
Limited Partners Capital Account [Line Items]
Distributions per annum	6.00%
Distributions per annum (in dollars per share)	$ 1.50
Units issued (in shares)	680,000	680,000
Units outstanding (in shares)	680,000	680,000
Redemption values	$ 17,000	$ 17,000

Partners' Capital - Narrative (

Partners' Capital - Narrative (Details) - AIMCO PROPERTIES, L.P. [Member] - USD ($) $ / shares in Units, $ in Millions	Feb. 03, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Redeemable partnership preferred units redeemed for cash during period (in units)		169,000	10,000	67,000
Redeemable partnership preferred units redeemed in exchange for shares during period (in units)		0
Common OP Units redeemed in exchange for cash during period (in units)		129,000	224,000	268,000
Common OP Units redeemed in exchange for shares during period		127,000	0	0
Dividends declared per common share/unit (in dollars per share)		$ 1.56	$ 1.52	$ 1.44
Special Distribution [Member]
Related Party Transaction [Line Items]
Cash dividends on common stock declared	$ 72.7
Common shares issued in special dividend (in shares)	4,800,000
Special distribution, cash paid in lieu of fractional shares	$ 0.4

Partners' Capital - Reconciliat

Partners' Capital - Reconciliation of Preferred OP Units (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Temporary Equity [Line Items]
Balance at January 1	$ 101,291
Balance at December 31	97,064
AIMCO PROPERTIES, L.P. [Member]
Temporary Equity [Line Items]
Balance at January 1	101,291
Preferred distributions	(7,708)
Redemption of preferred units	(4,227)
Net income	7,708
Balance at December 31	$ 97,064

Share-Based Compensation (Detai

Share-Based Compensation (Details Textual) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unvested compensation cost not yet recognized for options and restricted stock awards	$ 10.3
Weighted average period over which unvested compensation cost expected to be recognized	1 year 7 months 6 days
Restricted Stock [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest period	4 years
Requisite service period	4 years
Aggregate fair value of restricted stock awards that vested	$ 13.7	$ 8.4	$ 6
Employee Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest period	4 years
Term of stock options	10 years
Requisite service period	4 years
Stock options outstanding, aggregate intrinsic value	$ 7.3
Stock options outstanding, weighted average remaining contractual term	6 years
Stock options exercisable, aggregate intrinsic value	$ 5.9
Stock options exercisable, weighted average remaining contractual term	5 years 6 months
Intrinsic value of stock options exercised	$ 0.1	$ 0	$ 7.1
TSR Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
TSR restricted shares performance measurement period	3 years
Term of stock options	10 years
Options granted, weighted average grant-date fair value (dollars per share)	$ 11.39
TSR Stock Awards [Member] | NAREIT Apartment Index [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted percentage of index used to compare to TSR	60.00%
TSR Stock Awards [Member] | MSCI US REIT Index [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted percentage of index used to compare to TSR	40.00%
TSR LTIP Units [Member] | 36 Months After Grant Date [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage, TSR restricted stock	50.00%
TSR LTIP Units [Member] | 48 Months After Grant Date [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage, TSR restricted stock	50.00%
2015 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available to be granted under plan (in shares)	3.9

Share-Based Compensation - Tota

Share-Based Compensation - Total Compensation Cost Recognized for Share-based Awards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-based compensation expense	$ 8,146	$ 8,550	$ 7,877
Capitalized share-based compensation	962	1,215	1,374
Total share-based compensation	$ 9,108	$ 9,765	$ 9,251

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Activity for Outstanding Stock Options (Details) - Employee Stock Option [Member] - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Options
Beginning balance (in shares)	646	648	675
Granted (in shares)	0	0	184
Exercised (in shares)	(5)	(2)	(211)
Forfeited (in shares)	0	0	0
Ending balance (in shares)	641	646	648
Exercisable at end of year (in shares)	458	186	128
Weighted Average Exercise Price, Stock Options
Beginning balance (in dollars per share)	$ 40.12	$ 40.08	$ 29.55
Granted (in dollars per share)	0	0	44.07
Exercised (in dollars per share)	8.92	28.33	9.90
Forfeited (in dollars per share)	0	0	0
Ending balance (in dollars per share)	40.30	40.12	40.08
Exercisable (in dollars per share)	$ 38.78	$ 38.18	$ 37.59

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Activity for Restricted Stock Awards (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Time-Based Restricted Stock Awards [Member]
Number of Shares
Unvested (in shares)	121	155	241
Granted (in shares)	48	49	44
Vested (in shares)	(75)	(83)	(130)
Unvested (in shares)	92	121	155
Forfeited (in shares)	(2)
Weighted Average Grant-Date Fair Value
Unvested (in dollars per share)	$ 40.82	$ 37.63	$ 33.61
Granted (in dollars per share)	47.71	40.01	44.07
Vested (in dollars per share)	42.76	34.42	32.35
Forfeited (in dollars per share)	38.80
Unvested (in dollars per share)	$ 42.86	$ 40.82	$ 37.63
TSR Restricted Stock Awards [Member]
Number of Shares
Unvested (in shares)	171	246	208
Granted (in shares)	39	44	38
Vested (in shares)	(213)	(119)	0
Unvested (in shares)	213	171	246
Change in awards (in shares)	216
Weighted Average Grant-Date Fair Value
Unvested (in dollars per share)	$ 41.65	$ 40.70	$ 39.66
Granted (in dollars per share)	54.73	41.71	46.39
Vested (in dollars per share)	39.67	39.72	0
Unvested (in dollars per share)	43.99	$ 41.65	$ 40.70
Change in awards (in dollars per share)	$ 39.67
TSR LTIP I Units [Member]
Number of Shares
Unvested (in shares)	93	45	0
Granted (in shares)	6	48	45
Unvested (in shares)	99	93	45
Weighted Average Grant-Date Fair Value
Unvested (in dollars per share)	$ 43.78	$ 46.21	$ 0
Granted (in dollars per share)	55.17	41.48	46.21
Unvested (in dollars per share)	$ 44.38	$ 43.78	$ 46.21
TSR LTIP II Units [Member]
Number of Shares
Unvested (in shares)	243	0
Granted (in shares)	356	243
Unvested (in shares)	599	243	0
Weighted Average Grant-Date Fair Value
Unvested (in dollars per share)	$ 8.29	$ 0
Granted (in dollars per share)	12.03	8.29
Unvested (in dollars per share)	$ 10.51	$ 8.29	$ 0

Share-Based Compensation - Assu

Share-Based Compensation - Assumptions Used in the Determination of Grant-Date Fair Value of Awards (Details) - TSR Stock Awards [Member] - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date market value of a common share	$ 49.24	$ 40.95	$ 44.07
Risk-free interest rate, minimum	2.59%	2.32%	1.57%
Risk-free interest rate, maximum	2.66%	2.68%	2.22%
Dividend yield	3.09%	3.52%	3.27%
Derived vesting period of TSR Restricted Stock and TSR LTIP I units	3 years 4 months 24 days	3 years 4 months 24 days	3 years 4 months 24 days
Weighted average expected term of TSR Stock Options and LTIP II units	5 years 9 months 18 days	5 years 7 months 6 days	5 years 9 months 18 days
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility	19.08%	17.64%	21.33%
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected volatility	19.24%	18.02%	23.00%

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Liabilities and Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax liabilities:
Real estate and real estate partnership basis differences	$ 126,269	$ 12,058
Deferred tax assets:
Tax credit carryforwards	53,776	67,530
Net operating, capital and other loss carryforwards	6,147	7,022
Accruals and expenses	6,138	7,432
Management contracts and other	1,379	2,064
Total deferred tax assets	67,440	84,048
Valuation allowance	(4,766)	(4,930)
Net deferred tax liabilities	$ (63,595)
Net deferred tax assets		$ 67,060

Income Taxes (Details Textual)

Income Taxes (Details Textual) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Operating loss carryforwards	$ 6,100
Valuation allowance	4,800
Net deferred tax asset related to tax credit carryforwards	53,800
Consolidated income (loss) subject to tax	(21,200)	$ 158,600	$ (55,600)
Consolidated income (loss) subject to tax foreign subsidiary	(7,700)
Cash paid for income taxes	$ 12,238	$ 11,522	$ 7,401
Minimum [Member]
Income Taxes [Line Items]
Expiration years of net operating loss carryforwards	Dec. 31, 2020
Tax credit carryforward, expiration date	Dec. 31, 2035
Maximum [Member]
Income Taxes [Line Items]
Expiration years of net operating loss carryforwards	Dec. 31, 2038
Tax credit carryforward, expiration date	Dec. 31, 2039
1001 Brickell Bay Drive [Member]
Income Taxes [Line Items]
Deferred tax liability	$ 148,800

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of unrecognized tax benefits
Balance at January 1	$ 2,618	$ 2,476	$ 2,286
Additions based on tax position taken in current year	2,758
Additions based on tax positions related to prior years	226	142	190
Reductions as a result of a lapse of the applicable statutes	(522)
Balance at December 31	$ 5,080	$ 2,618	$ 2,476

Income Taxes - Components of In

Income Taxes - Components of Income Tax Benefit or Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 6,115	$ 11,269	$ (938)
State	8,982	10,537	525
Total current	15,097	21,806	(413)
Deferred:
Federal	(12,891)	(29,243)	(10,908)
State	(5,341)	(5,590)	(3,621)
Revaluation of deferred taxes due to change in tax rate	0	0	(15,894)
Total deferred	(18,232)	(34,833)	(30,423)
Total benefit	$ (3,135)	$ (13,027)	$ (30,836)

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Income Tax Attributable to Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amount
Tax (benefit) provision at United States statutory rates on consolidated income or loss subject to tax	$ (4,442)	$ 33,296	$ (19,459)
United States branch profits tax on losses of a foreign subsidiary	(1,813)	0	0
State income tax expense, net of federal tax (benefit) expense	3,935	12,252	(1,769)
Establishment of deferred tax asset related to partnership basis difference	0	0	(3,501)
Effect of permanent differences	(138)	302	(1,629)
Tax effect of intercompany transactions	0	(33,250)	0
Tax credits	(667)	(6,897)	(9,607)
Tax reform revaluation	0	288	(15,894)
(Decrease) increase in valuation allowance	(164)	(20,434)	21,023
Other	154	1,416	0
Total income tax benefit	$ (3,135)	$ (13,027)	$ (30,836)
Percent
Tax (benefit) provision at United States statutory rates on consolidated income or loss subject to tax	21.00%	21.00%	35.00%
United States branch profits tax on losses of a foreign subsidiary	8.60%	0.00%	0.00%
State income tax expense, net of federal tax (benefit) expense	(18.60%)	7.70%	3.20%
Establishment of deferred tax asset related to partnership basis difference	0.00%	0.00%	6.30%
Effect of permanent differences	0.70%	0.20%	2.90%
Tax effect of intercompany transactions	0.00%	(21.00%)	0.00%
Tax credits	3.20%	(4.40%)	17.30%
Tax reform revaluation		0.002	0.286
(Decrease) increase in valuation allowance	0.80%	(12.90%)	(37.80%)
Other	(0.70%)	0.90%	0.00%
Total income tax benefit	15.00%	(8.30%)	55.50%

Income Taxes - Reconciliation_3

Income Taxes - Reconciliation of Income Tax Attributable to Operations (Parenthetical) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Tax Credit Carryforward [Line Items]
Valuation allowance against deferred tax assets associated with rehabilitation tax credits due to lower federal tax rate under the 2017 Act	$ 4,766	$ 4,930
State [Member]
Tax Credit Carryforward [Line Items]
Valuation allowance carryforwards	$ 200
Low-Income Housing and Rehabilitation Tax Credit Carryforward [Member]
Tax Credit Carryforward [Line Items]
Valuation allowance against deferred tax assets associated with rehabilitation tax credits due to lower federal tax rate under the 2017 Act			$ 15,400

Income Taxes - Schedule of Divi

Income Taxes - Schedule of Dividends Per Share Held (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amount
Ordinary income	$ 0.66	$ 0.51	$ 0.75
Capital gains	1.29	0.93	0.51
Qualified dividends	0.66	0	0.02
Unrecaptured Section 1250 gain	0.58	0.08	0.16
Total	$ 3.19	$ 1.52	$ 1.44
Percentage
Ordinary income	20.70%	33.40%	51.50%
Capital gains	40.40%	61.20%	35.70%
Qualified dividends	20.70%	0.00%	1.60%
Unrecaptured Section 1250 gain	18.20%	5.40%	11.20%
Total	100.00%	100.00%	100.00%

Earnings per Share and per Un_3

Earnings per Share and per Unit - Reconciliations of Numerator and Denominator in Calculations of Basic and Diluted Earnings per Share and per Unit (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Earnings Per Share and Per Unit [Line Items]
Basic and dilutive net income attributable to Aimco common stockholders	$ 133,339	$ 2,003	$ 59,234	$ 271,568	$ 5,226	$ 567,029	$ 2,817	$ 81,525	$ 466,144	$ 656,597	$ 306,861
Basic weighted-average Common Stock outstanding									147,718	151,152	151,595
Dilutive share equivalents outstanding									226	182	465
Dilutive weighted-average Common Stock outstanding									147,944	151,334	152,060
Earnings per share – basic	$ 0.90	$ 0.01	$ 0.40	$ 1.88	$ 0.04	$ 3.73	$ 0.02	$ 0.54	$ 3.16	$ 4.34	$ 2.02
Earnings per share – dilutive	$ 0.90	$ 0.01	$ 0.40	$ 1.88	$ 0.04	$ 3.73	$ 0.02	$ 0.54	$ 3.15	$ 4.34	$ 2.02
Non-dilutive share equivalents outstanding										269	184
AIMCO Properties, LP [Member]
Schedule of Earnings Per Share and Per Unit [Line Items]
Basic and dilutive net income attributable to Aimco common stockholders									$ 492,177	$ 690,874	$ 321,300
Basic weighted-average Common Stock outstanding									155,882	158,890	158,793
Dilutive share equivalents outstanding									335	183	464
Dilutive weighted-average Common Stock outstanding									156,217	159,073	159,257
Earnings per share – basic									$ 3.16	$ 4.35	$ 2.02
Earnings per share – dilutive									$ 3.15	$ 4.34	$ 2.02
Non-dilutive share equivalents outstanding										269	184

Earnings per Share and per Un_4

Earnings per Share and per Unit (Details Textual) shares in Millions	Dec. 31, 2019shares
Earnings Per Share [Abstract]
Number of shares potentially redeemable for (in shares)	1.9

Fair Value Measurements (Detail

Fair Value Measurements (Details Textual) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Amortized cost of the investment in available-for-sale debt securities	$ 90	$ 83.6
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	1 year 7 months 6 days

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Fair Value for AFS Debt Securities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	$ 94,251	$ 83,587
Fair value recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	94,251	88,457
Fair value recurring [Member] | Level 1 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	0	0
Fair value recurring [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	94,251	88,457
Fair value recurring [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
AFS debt securities	$ 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] - Fair value Non-recurring [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Carrying Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Non-recourse property debt	$ 4,251,339	$ 3,937,000
Fair Value [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Non-recourse property debt	$ 4,298,630	$ 3,893,171

Business Segments (Details Text

Business Segments (Details Textual)	12 Months Ended
	Dec. 31, 2019Propertyapartment_homeSegmentoffice_building
Business Segments (Textual) [Abstract]
Number of reportable segments | Segment	4
Wholly And Partially Owned Consolidated Properties [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	120
Number of apartment homes in apartment communities | apartment_home	32,697
Wholly And Partially Owned Consolidated Properties [Member] | Same Store [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	91
Number of apartment homes in apartment communities | apartment_home	26,649
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	7
Number of apartment homes in apartment communities | apartment_home	3,143
Wholly And Partially Owned Consolidated Properties [Member] | Acquisition [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	7
Number of apartment homes in apartment communities | apartment_home	1,590
Wholly And Partially Owned Consolidated Properties [Member] | Other Real Estate [Member]
Business Segments (Textual) [Abstract]
Number of owned and managed apartment communities in segments | Property	15
Number of apartment homes in apartment communities | apartment_home	1,315
Wholly And Partially Owned Consolidated Properties [Member] | 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								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary information for the reportable segments
Total revenues	$ 230,032	$ 229,827	$ 224,200	$ 230,235	$ 232,022	$ 242,481	$ 250,187	$ 247,720	$ 914,294	$ 972,410	$ 1,005,437
Other operating expenses not allocated to segments									446,300	448,753	492,328
Total operating expenses									757,521	756,654	811,454
Proportionate property net operating income									156,773	215,756	193,983
Other items included in income before income tax benefit									348,119	487,820	122,260
Income before income tax benefit									504,892	703,576	316,243
Real Estate [Member]
Summary information for the reportable segments
Total revenues									914,294	922,593	918,148
Property operating expenses									311,221	307,901	319,126
Segment Reconciling Items [Member]
Summary information for the reportable segments
Total revenues									33,450	31,442	39,776
Total operating expenses									31,140	29,323	29,782
Proportionate property net operating income									2,310	2,119	9,994
Income before income tax benefit									2,310	2,119	9,994
Segment Reconciling Items [Member] | Real Estate [Member]
Summary information for the reportable segments
Property operating expenses									31,140	29,323	29,782
Corporate Non-Segment [Member]
Summary information for the reportable segments
Total revenues									26,800	132,876	229,486
Other operating expenses not allocated to segments									446,300	448,753	492,328
Total operating expenses									487,228	499,430	569,913
Proportionate property net operating income									(460,428)	(366,554)	(340,427)
Other items included in income before income tax benefit									348,119	487,820	122,260
Income before income tax benefit									(112,309)	121,266	(218,167)
Corporate Non-Segment [Member] | Real Estate [Member]
Summary information for the reportable segments
Property operating expenses									40,928	50,677	77,585
Same Store [Member] | Operating Segments [Member]
Summary information for the reportable segments
Total revenues									691,379	665,835	626,311
Total operating expenses									181,802	177,466	171,167
Proportionate property net operating income									509,577	488,369	455,144
Income before income tax benefit									509,577	488,369	455,144
Same Store [Member] | Operating Segments [Member] | Real Estate [Member]
Summary information for the reportable segments
Property operating expenses									181,802	177,466	171,167
Redevelopment and Development [Member] | Operating Segments [Member]
Summary information for the reportable segments
Total revenues									75,522	76,687	72,995
Total operating expenses									27,919	27,836	26,471
Proportionate property net operating income									47,603	48,851	46,524
Income before income tax benefit									47,603	48,851	46,524
Redevelopment and Development [Member] | Operating Segments [Member] | Real Estate [Member]
Summary information for the reportable segments
Property operating expenses									27,919	27,836	26,471
Acquisition [Member] | Operating Segments [Member]
Summary information for the reportable segments
Total revenues									42,038	27,923
Total operating expenses									11,715	7,689
Proportionate property net operating income									30,323	20,234
Income before income tax benefit									30,323	20,234
Acquisition [Member] | Operating Segments [Member] | Real Estate [Member]
Summary information for the reportable segments
Property operating expenses									11,715	7,689
Other Real Estate [Member] | Operating Segments [Member]
Summary information for the reportable segments
Total revenues									45,105	37,647	36,869
Total operating expenses									17,717	14,910	14,121
Proportionate property net operating income									27,388	22,737	22,748
Income before income tax benefit									27,388	22,737	22,748
Other Real Estate [Member] | Operating Segments [Member] | Real Estate [Member]
Summary information for the reportable segments
Property operating expenses									$ 17,717	$ 14,910	$ 14,121

Business Segments - Reconciliat

Business Segments - Reconciliation of Assets from Segment to Consolidated (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Total assets	$ 6,828,739	$ 6,190,004
Corporate Non-Segment [Member]
Segment Reporting Information [Line Items]
Total assets	629,001	494,716
Same Store [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	3,982,586	4,068,880
Redevelopment and Development [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	946,390	792,126
Acquisition [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	623,037	507,190
Other Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Total assets	$ 647,725	$ 327,092

Business Segments - Capital Add

Business Segments - Capital Additions Related to Segments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Capital additions	$ 401,575	$ 330,514	$ 311,886
Same Store [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Capital additions	153,944	171,869	215,130
Redevelopment and Development [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Capital additions	194,498	138,103	84,712
Acquisition [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Capital additions	33,122	14,228
Other Real Estate [Member] | Operating Segments [Member]
Segment Reporting Information [Line Items]
Capital additions	$ 20,011	$ 6,314	$ 12,044

Unaudited Summarized Consolid_3

Unaudited Summarized Consolidated Quarterly Information - Summary of Unaudited Consolidated Quarterly Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summarized unaudited consolidated quarterly information
Total revenues	$ 230,032	$ 229,827	$ 224,200	$ 230,235	$ 232,022	$ 242,481	$ 250,187	$ 247,720	$ 914,294	$ 972,410	$ 1,005,437
Net income	142,766	3,970	69,996	291,295	9,840	603,917	7,156	95,690	508,027	716,603	347,079
Net income attributable to Aimco common stockholders	$ 133,339	$ 2,003	$ 59,234	$ 271,568	$ 5,226	$ 567,029	$ 2,817	$ 81,525	$ 466,144	$ 656,597	$ 306,861
Net income attributable to Aimco per common share – basic	$ 0.90	$ 0.01	$ 0.40	$ 1.88	$ 0.04	$ 3.73	$ 0.02	$ 0.54	$ 3.16	$ 4.34	$ 2.02
Net income attributable to Aimco per common share – diluted	$ 0.90	$ 0.01	$ 0.40	$ 1.88	$ 0.04	$ 3.73	$ 0.02	$ 0.54	$ 3.15	$ 4.34	$ 2.02
AIMCO PROPERTIES, L.P. [Member]
Summarized unaudited consolidated quarterly information
Total revenues	$ 230,032	$ 229,827	$ 224,200	$ 230,235	$ 232,022	$ 242,481	$ 250,187	$ 247,720
Net income	142,766	3,970	69,996	291,295	9,840	603,917	7,156	95,690
Net income attributable to Aimco common stockholders	$ 140,583	$ 2,138	$ 62,817	$ 286,639	$ 5,551	$ 597,100	$ 2,949	$ 85,274
Net income attributable to Aimco per common share – basic	$ 0.90	$ 0.01	$ 0.40	$ 1.88	$ 0.04	$ 3.73	$ 0.02	$ 0.54
Net income attributable to Aimco per common share – diluted	$ 0.90	$ 0.01	$ 0.40	$ 1.88	$ 0.04	$ 3.72	$ 0.02	$ 0.54

Schedule III_ Real Estate and A

Schedule III: Real Estate and Accumulated Depreciation - Schedule of Real Estate and Accumulated Depreciation (Details) - Continuing Operations [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)apartment_home
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes | apartment_home	32,697
Initial Cost, Land	$ 1,958,523
Initial Cost, Buildings and Improvements	3,562,176
Costs Capitalized Subsequent to Consolidation	3,306,367
Land	1,869,048
Buildings and Improvements	6,868,543
Total	8,737,591
Accumulated Depreciation (AD)	(2,718,284)
Total Cost Net of Accumulated Depreciation	6,019,307
Encumbrances	$ 4,251,339
Same Store Sales [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes | apartment_home	26,649
Initial Cost, Land	$ 1,411,619
Initial Cost, Buildings and Improvements	2,597,010
Costs Capitalized Subsequent to Consolidation	2,149,561
Land	1,322,144
Buildings and Improvements	4,746,571
Total	6,068,715
Accumulated Depreciation (AD)	(2,188,175)
Total Cost Net of Accumulated Depreciation	3,880,540
Encumbrances	$ 3,579,476
Same Store Sales [Member] | 100 Forest Place [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 31, 1997
Location	Oak Park, IL
Year Built	1987
Number of apartment homes | apartment_home	234
Initial Cost, Land	$ 2,664
Initial Cost, Buildings and Improvements	18,815
Costs Capitalized Subsequent to Consolidation	11,145
Land	2,664
Buildings and Improvements	29,960
Total	32,624
Accumulated Depreciation (AD)	(16,676)
Total Cost Net of Accumulated Depreciation	15,948
Encumbrances	$ 34,453
Same Store Sales [Member] | 118-122 West 23rd Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jun. 30, 2012
Location	New York, NY
Year Built	1987
Number of apartment homes | apartment_home	42
Initial Cost, Land	$ 14,985
Initial Cost, Buildings and Improvements	23,459
Costs Capitalized Subsequent to Consolidation	6,914
Land	14,985
Buildings and Improvements	30,373
Total	45,358
Accumulated Depreciation (AD)	(10,461)
Total Cost Net of Accumulated Depreciation	34,897
Encumbrances	$ 16,999
Same Store Sales [Member] | 1045 on the Park Apartments Homes [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Jul. 31, 2013
Location	Atlanta, GA
Year Built	2012
Number of apartment homes | apartment_home	30
Initial Cost, Land	$ 2,793
Initial Cost, Buildings and Improvements	6,662
Costs Capitalized Subsequent to Consolidation	819
Land	2,793
Buildings and Improvements	7,481
Total	10,274
Accumulated Depreciation (AD)	(1,739)
Total Cost Net of Accumulated Depreciation	8,535
Encumbrances	$ 0
Same Store Sales [Member] | 1582 First Avenue [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 31, 2005
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	17
Initial Cost, Land	$ 4,281
Initial Cost, Buildings and Improvements	752
Costs Capitalized Subsequent to Consolidation	518
Land	4,281
Buildings and Improvements	1,270
Total	5,551
Accumulated Depreciation (AD)	(650)
Total Cost Net of Accumulated Depreciation	4,901
Encumbrances	$ 2,226
Same Store Sales [Member] | 21 Fitzsimons [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Aug. 31, 2014
Location	Aurora, CO
Year Built	2008
Number of apartment homes | apartment_home	600
Initial Cost, Land	$ 12,864
Initial Cost, Buildings and Improvements	104,720
Costs Capitalized Subsequent to Consolidation	27,677
Land	12,864
Buildings and Improvements	132,397
Total	145,261
Accumulated Depreciation (AD)	(26,098)
Total Cost Net of Accumulated Depreciation	119,163
Encumbrances	$ 89,413
Same Store Sales [Member] | 2200 Grace [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 31, 1999
Location	Lombard, IL
Year Built	1971
Number of apartment homes | apartment_home	72
Initial Cost, Land	$ 642
Initial Cost, Buildings and Improvements	7,788
Costs Capitalized Subsequent to Consolidation	294
Land	642
Buildings and Improvements	8,082
Total	8,724
Accumulated Depreciation (AD)	(4,549)
Total Cost Net of Accumulated Depreciation	4,175
Encumbrances	$ 7,448
Same Store Sales [Member] | 2900 on First Apartments [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Oct. 31, 2008
Location	Seattle, WA
Year Built	1989
Number of apartment homes | apartment_home	135
Initial Cost, Land	$ 19,070
Initial Cost, Buildings and Improvements	17,518
Costs Capitalized Subsequent to Consolidation	34,356
Land	19,070
Buildings and Improvements	51,874
Total	70,944
Accumulated Depreciation (AD)	(29,578)
Total Cost Net of Accumulated Depreciation	41,366
Encumbrances	$ 13,594
Same Store Sales [Member] | 306 East 89th Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jul. 31, 2004
Location	New York, NY
Year Built	1930
Number of apartment homes | apartment_home	20
Initial Cost, Land	$ 2,680
Initial Cost, Buildings and Improvements	1,006
Costs Capitalized Subsequent to Consolidation	1,099
Land	2,680
Buildings and Improvements	2,105
Total	4,785
Accumulated Depreciation (AD)	(1,046)
Total Cost Net of Accumulated Depreciation	3,739
Encumbrances	$ 1,816
Same Store Sales [Member] | 322-324 East 61st Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 31, 2005
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	40
Initial Cost, Land	$ 6,372
Initial Cost, Buildings and Improvements	2,224
Costs Capitalized Subsequent to Consolidation	1,598
Land	6,372
Buildings and Improvements	3,822
Total	10,194
Accumulated Depreciation (AD)	(2,009)
Total Cost Net of Accumulated Depreciation	8,185
Encumbrances	$ 3,339
Same Store Sales [Member] | 3400 Avenue of the Arts [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Mar. 31, 2002
Location	Costa Mesa, CA
Year Built	1987
Number of apartment homes | apartment_home	770
Initial Cost, Land	$ 57,241
Initial Cost, Buildings and Improvements	65,506
Costs Capitalized Subsequent to Consolidation	88,112
Land	57,241
Buildings and Improvements	153,618
Total	210,859
Accumulated Depreciation (AD)	(92,205)
Total Cost Net of Accumulated Depreciation	118,654
Encumbrances	$ 142,476
Same Store Sales [Member] | 452 East 78th Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 31, 2004
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	12
Initial Cost, Land	$ 1,982
Initial Cost, Buildings and Improvements	608
Costs Capitalized Subsequent to Consolidation	600
Land	1,982
Buildings and Improvements	1,208
Total	3,190
Accumulated Depreciation (AD)	(548)
Total Cost Net of Accumulated Depreciation	2,642
Encumbrances	$ 0
Same Store Sales [Member] | 510 East 88th Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 31, 2004
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	20
Initial Cost, Land	$ 3,163
Initial Cost, Buildings and Improvements	1,002
Costs Capitalized Subsequent to Consolidation	653
Land	3,163
Buildings and Improvements	1,655
Total	4,818
Accumulated Depreciation (AD)	(726)
Total Cost Net of Accumulated Depreciation	4,092
Encumbrances	$ 0
Same Store Sales [Member] | 514-516 East 88th Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 31, 2005
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	36
Initial Cost, Land	$ 6,282
Initial Cost, Buildings and Improvements	2,168
Costs Capitalized Subsequent to Consolidation	1,617
Land	6,282
Buildings and Improvements	3,785
Total	10,067
Accumulated Depreciation (AD)	(1,868)
Total Cost Net of Accumulated Depreciation	8,199
Encumbrances	$ 3,620
Same Store Sales [Member] | Axiom [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Apr. 30, 2015
Location	Cambridge, MA
Year Built	2015
Number of apartment homes | apartment_home	115
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	63,612
Costs Capitalized Subsequent to Consolidation	2,665
Land	0
Buildings and Improvements	66,277
Total	66,277
Accumulated Depreciation (AD)	(11,504)
Total Cost Net of Accumulated Depreciation	54,773
Encumbrances	$ 32,253
Same Store Sales [Member] | Bank Lofts [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Apr. 30, 2001
Location	Denver, CO
Year Built	1920
Number of apartment homes | apartment_home	125
Initial Cost, Land	$ 3,525
Initial Cost, Buildings and Improvements	9,045
Costs Capitalized Subsequent to Consolidation	5,797
Land	3,525
Buildings and Improvements	14,842
Total	18,367
Accumulated Depreciation (AD)	(8,109)
Total Cost Net of Accumulated Depreciation	10,258
Encumbrances	$ 10,218
Same Store Sales [Member] | Bay Ridge at Nashua [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 31, 2003
Location	Nashua, NH
Year Built	1984
Number of apartment homes | apartment_home	412
Initial Cost, Land	$ 3,262
Initial Cost, Buildings and Improvements	40,713
Costs Capitalized Subsequent to Consolidation	17,995
Land	3,262
Buildings and Improvements	58,708
Total	61,970
Accumulated Depreciation (AD)	(26,731)
Total Cost Net of Accumulated Depreciation	35,239
Encumbrances	$ 50,638
Same Store Sales [Member] | Bayberry Hill Estates [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2002
Location	Framingham, MA
Year Built	1971
Number of apartment homes | apartment_home	424
Initial Cost, Land	$ 19,944
Initial Cost, Buildings and Improvements	35,945
Costs Capitalized Subsequent to Consolidation	25,151
Land	19,944
Buildings and Improvements	61,096
Total	81,040
Accumulated Depreciation (AD)	(30,503)
Total Cost Net of Accumulated Depreciation	50,537
Encumbrances	$ 44,197
Same Store Sales [Member] | Bluffs at Pacifica, The [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 31, 2006
Location	Pacifica, CA
Year Built	1963
Number of apartment homes | apartment_home	64
Initial Cost, Land	$ 8,108
Initial Cost, Buildings and Improvements	4,132
Costs Capitalized Subsequent to Consolidation	17,349
Land	8,108
Buildings and Improvements	21,481
Total	29,589
Accumulated Depreciation (AD)	(11,400)
Total Cost Net of Accumulated Depreciation	18,189
Encumbrances	$ 0
Same Store Sales [Member] | Boston Lofts [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Apr. 30, 2001
Location	Denver, CO
Year Built	1890
Number of apartment homes | apartment_home	158
Initial Cost, Land	$ 3,446
Initial Cost, Buildings and Improvements	20,589
Costs Capitalized Subsequent to Consolidation	6,715
Land	3,446
Buildings and Improvements	27,304
Total	30,750
Accumulated Depreciation (AD)	(14,706)
Total Cost Net of Accumulated Depreciation	16,044
Encumbrances	$ 14,927
Same Store Sales [Member] | Boulder Creek [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 31, 1994
Location	Boulder, CO
Year Built	1973
Number of apartment homes | apartment_home	221
Initial Cost, Land	$ 754
Initial Cost, Buildings and Improvements	7,730
Costs Capitalized Subsequent to Consolidation	20,791
Land	754
Buildings and Improvements	28,521
Total	29,275
Accumulated Depreciation (AD)	(20,708)
Total Cost Net of Accumulated Depreciation	8,567
Encumbrances	$ 37,861
Same Store Sales [Member] | Broadcast Center [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	Los Angeles, CA
Year Built	1990
Number of apartment homes | apartment_home	279
Initial Cost, Land	$ 29,407
Initial Cost, Buildings and Improvements	41,244
Costs Capitalized Subsequent to Consolidation	31,856
Land	29,407
Buildings and Improvements	73,100
Total	102,507
Accumulated Depreciation (AD)	(32,455)
Total Cost Net of Accumulated Depreciation	70,052
Encumbrances	$ 96,880
Same Store Sales [Member] | Broadway Lofts [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 30, 2012
Location	San Diego, CA
Year Built	1909
Number of apartment homes | apartment_home	84
Initial Cost, Land	$ 5,367
Initial Cost, Buildings and Improvements	14,442
Costs Capitalized Subsequent to Consolidation	7,647
Land	5,367
Buildings and Improvements	22,089
Total	27,456
Accumulated Depreciation (AD)	(6,031)
Total Cost Net of Accumulated Depreciation	21,425
Encumbrances	$ 11,298
Same Store Sales [Member] | Burke Shire Commons [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2001
Location	Burke, VA
Year Built	1986
Number of apartment homes | apartment_home	360
Initial Cost, Land	$ 4,867
Initial Cost, Buildings and Improvements	23,617
Costs Capitalized Subsequent to Consolidation	19,855
Land	4,867
Buildings and Improvements	43,472
Total	48,339
Accumulated Depreciation (AD)	(27,328)
Total Cost Net of Accumulated Depreciation	21,011
Encumbrances	$ 56,855
Same Store Sales [Member] | Calhoun Beach Club [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 31, 1998
Location	Minneapolis, MN
Year Built	1928
Number of apartment homes | apartment_home	332
Initial Cost, Land	$ 11,708
Initial Cost, Buildings and Improvements	73,334
Costs Capitalized Subsequent to Consolidation	65,713
Land	11,708
Buildings and Improvements	139,047
Total	150,755
Accumulated Depreciation (AD)	(85,259)
Total Cost Net of Accumulated Depreciation	65,496
Encumbrances	$ 0
Same Store Sales [Member] | Canyon Terrace [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	Saugus, CA
Year Built	1984
Number of apartment homes | apartment_home	130
Initial Cost, Land	$ 7,508
Initial Cost, Buildings and Improvements	6,601
Costs Capitalized Subsequent to Consolidation	7,008
Land	7,508
Buildings and Improvements	13,609
Total	21,117
Accumulated Depreciation (AD)	(7,711)
Total Cost Net of Accumulated Depreciation	13,406
Encumbrances	$ 0
Same Store Sales [Member] | Cedar Rim [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Apr. 30, 2000
Location	Newcastle, WA
Year Built	1980
Number of apartment homes | apartment_home	104
Initial Cost, Land	$ 761
Initial Cost, Buildings and Improvements	5,218
Costs Capitalized Subsequent to Consolidation	13,873
Land	761
Buildings and Improvements	19,091
Total	19,852
Accumulated Depreciation (AD)	(14,179)
Total Cost Net of Accumulated Depreciation	5,673
Encumbrances	$ 0
Same Store Sales [Member] | Charlesbank Apartment Homes [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Sep. 30, 2013
Location	Watertown, MA
Year Built	2012
Number of apartment homes | apartment_home	44
Initial Cost, Land	$ 3,399
Initial Cost, Buildings and Improvements	11,726
Costs Capitalized Subsequent to Consolidation	1,018
Land	3,399
Buildings and Improvements	12,744
Total	16,143
Accumulated Depreciation (AD)	(2,931)
Total Cost Net of Accumulated Depreciation	13,212
Encumbrances	$ 0
Same Store Sales [Member] | Chestnut Hall [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Oct. 31, 2006
Location	Philadelphia, PA
Year Built	1923
Number of apartment homes | apartment_home	315
Initial Cost, Land	$ 12,338
Initial Cost, Buildings and Improvements	14,299
Costs Capitalized Subsequent to Consolidation	13,223
Land	12,338
Buildings and Improvements	27,522
Total	39,860
Accumulated Depreciation (AD)	(13,266)
Total Cost Net of Accumulated Depreciation	26,594
Encumbrances	$ 35,834
Same Store Sales [Member] | Creekside [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 31, 2000
Location	Denver, CO
Year Built	1974
Number of apartment homes | apartment_home	328
Initial Cost, Land	$ 3,189
Initial Cost, Buildings and Improvements	12,698
Costs Capitalized Subsequent to Consolidation	7,404
Land	3,189
Buildings and Improvements	20,102
Total	23,291
Accumulated Depreciation (AD)	(13,579)
Total Cost Net of Accumulated Depreciation	9,712
Encumbrances	$ 11,066
Same Store Sales [Member] | Crescent at West Hollywood, The [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Mar. 31, 2002
Location	West Hollywood, CA
Year Built	1985
Number of apartment homes | apartment_home	130
Initial Cost, Land	$ 15,765
Initial Cost, Buildings and Improvements	10,215
Costs Capitalized Subsequent to Consolidation	8,281
Land	15,765
Buildings and Improvements	18,496
Total	34,261
Accumulated Depreciation (AD)	(12,337)
Total Cost Net of Accumulated Depreciation	21,924
Encumbrances	$ 39,336
Same Store Sales [Member] | Elm Creek [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 31, 1997
Location	Elmhurst, IL
Year Built	1987
Number of apartment homes | apartment_home	400
Initial Cost, Land	$ 5,910
Initial Cost, Buildings and Improvements	30,830
Costs Capitalized Subsequent to Consolidation	32,788
Land	5,910
Buildings and Improvements	63,618
Total	69,528
Accumulated Depreciation (AD)	(35,969)
Total Cost Net of Accumulated Depreciation	33,559
Encumbrances	$ 50,296
Same Store Sales [Member] | Evanston Place [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 31, 1997
Location	Evanston, IL
Year Built	1990
Number of apartment homes | apartment_home	190
Initial Cost, Land	$ 3,232
Initial Cost, Buildings and Improvements	25,546
Costs Capitalized Subsequent to Consolidation	16,703
Land	3,232
Buildings and Improvements	42,249
Total	45,481
Accumulated Depreciation (AD)	(20,982)
Total Cost Net of Accumulated Depreciation	24,499
Encumbrances	$ 0
Same Store Sales [Member] | Four Quarters Habitat [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 31, 2006
Location	Miami, FL
Year Built	1976
Number of apartment homes | apartment_home	336
Initial Cost, Land	$ 2,379
Initial Cost, Buildings and Improvements	17,199
Costs Capitalized Subsequent to Consolidation	32,991
Land	2,379
Buildings and Improvements	50,190
Total	52,569
Accumulated Depreciation (AD)	(30,456)
Total Cost Net of Accumulated Depreciation	22,113
Encumbrances	$ 50,716
Same Store Sales [Member] | Foxchase [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Dec. 31, 1997
Location	Alexandria, VA
Year Built	1940
Number of apartment homes | apartment_home	2,113
Initial Cost, Land	$ 15,496
Initial Cost, Buildings and Improvements	96,062
Costs Capitalized Subsequent to Consolidation	64,213
Land	15,496
Buildings and Improvements	160,275
Total	175,771
Accumulated Depreciation (AD)	(92,368)
Total Cost Net of Accumulated Depreciation	83,403
Encumbrances	$ 218,337
Same Store Sales [Member] | Georgetown [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2002
Location	Framingham, MA
Year Built	1964
Number of apartment homes | apartment_home	207
Initial Cost, Land	$ 12,351
Initial Cost, Buildings and Improvements	13,168
Costs Capitalized Subsequent to Consolidation	4,896
Land	12,351
Buildings and Improvements	18,064
Total	30,415
Accumulated Depreciation (AD)	(9,068)
Total Cost Net of Accumulated Depreciation	21,347
Encumbrances	$ 14,355
Same Store Sales [Member] | Georgetown II [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Aug. 31, 2002
Location	Framingham, MA
Year Built	1958
Number of apartment homes | apartment_home	72
Initial Cost, Land	$ 4,577
Initial Cost, Buildings and Improvements	4,057
Costs Capitalized Subsequent to Consolidation	2,316
Land	4,577
Buildings and Improvements	6,373
Total	10,950
Accumulated Depreciation (AD)	(3,871)
Total Cost Net of Accumulated Depreciation	7,079
Encumbrances	$ 0
Same Store Sales [Member] | Hidden Cove [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 31, 1998
Location	Escondido, CA
Year Built	1983
Number of apartment homes | apartment_home	334
Initial Cost, Land	$ 3,043
Initial Cost, Buildings and Improvements	17,616
Costs Capitalized Subsequent to Consolidation	11,447
Land	3,043
Buildings and Improvements	29,063
Total	32,106
Accumulated Depreciation (AD)	(17,321)
Total Cost Net of Accumulated Depreciation	14,785
Encumbrances	$ 51,840
Same Store Sales [Member] | Hidden Cove II [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 31, 2007
Location	Escondido, CA
Year Built	1986
Number of apartment homes | apartment_home	118
Initial Cost, Land	$ 12,849
Initial Cost, Buildings and Improvements	6,530
Costs Capitalized Subsequent to Consolidation	5,439
Land	12,849
Buildings and Improvements	11,969
Total	24,818
Accumulated Depreciation (AD)	(5,881)
Total Cost Net of Accumulated Depreciation	18,937
Encumbrances	$ 20,160
Same Store Sales [Member] | Hillcreste [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	Century City, CA
Year Built	1989
Number of apartment homes | apartment_home	315
Initial Cost, Land	$ 35,862
Initial Cost, Buildings and Improvements	47,216
Costs Capitalized Subsequent to Consolidation	15,706
Land	35,862
Buildings and Improvements	62,922
Total	98,784
Accumulated Depreciation (AD)	(29,709)
Total Cost Net of Accumulated Depreciation	69,075
Encumbrances	$ 61,930
Same Store Sales [Member] | Hillmeade [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Nov. 30, 1994
Location	Nashville, TN
Year Built	1986
Number of apartment homes | apartment_home	288
Initial Cost, Land	$ 2,872
Initial Cost, Buildings and Improvements	16,070
Costs Capitalized Subsequent to Consolidation	22,103
Land	2,872
Buildings and Improvements	38,173
Total	41,045
Accumulated Depreciation (AD)	(22,434)
Total Cost Net of Accumulated Depreciation	18,611
Encumbrances	$ 26,756
Same Store Sales [Member] | Horizons West Apartments [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 31, 2006
Location	Pacifica, CA
Year Built	1970
Number of apartment homes | apartment_home	78
Initial Cost, Land	$ 8,887
Initial Cost, Buildings and Improvements	6,377
Costs Capitalized Subsequent to Consolidation	2,808
Land	8,887
Buildings and Improvements	9,185
Total	18,072
Accumulated Depreciation (AD)	(4,155)
Total Cost Net of Accumulated Depreciation	13,917
Encumbrances	$ 0
Same Store Sales [Member] | Hunt Club [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Sep. 30, 2000
Location	Gaithersburg, MD
Year Built	1986
Number of apartment homes | apartment_home	336
Initial Cost, Land	$ 17,859
Initial Cost, Buildings and Improvements	13,149
Costs Capitalized Subsequent to Consolidation	14,807
Land	17,859
Buildings and Improvements	27,956
Total	45,815
Accumulated Depreciation (AD)	(17,241)
Total Cost Net of Accumulated Depreciation	28,574
Encumbrances	$ 0
Same Store Sales [Member] | Hyde Park Tower [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Oct. 31, 2004
Location	Chicago, IL
Year Built	1990
Number of apartment homes | apartment_home	155
Initial Cost, Land	$ 4,731
Initial Cost, Buildings and Improvements	14,927
Costs Capitalized Subsequent to Consolidation	16,765
Land	4,731
Buildings and Improvements	31,692
Total	36,423
Accumulated Depreciation (AD)	(11,613)
Total Cost Net of Accumulated Depreciation	24,810
Encumbrances	$ 12,301
Same Store Sales [Member] | Indian Oaks [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	Simi Valley, CA
Year Built	1986
Number of apartment homes | apartment_home	254
Initial Cost, Land	$ 24,523
Initial Cost, Buildings and Improvements	15,801
Costs Capitalized Subsequent to Consolidation	12,124
Land	24,523
Buildings and Improvements	27,925
Total	52,448
Accumulated Depreciation (AD)	(14,829)
Total Cost Net of Accumulated Depreciation	37,619
Encumbrances	$ 26,944
Same Store Sales [Member] | Indigo [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Aug. 31, 2016
Location	Redwood City, CA
Year Built	2016
Number of apartment homes | apartment_home	463
Initial Cost, Land	$ 26,932
Initial Cost, Buildings and Improvements	296,116
Costs Capitalized Subsequent to Consolidation	3,561
Land	26,932
Buildings and Improvements	299,677
Total	326,609
Accumulated Depreciation (AD)	(35,408)
Total Cost Net of Accumulated Depreciation	291,201
Encumbrances	$ 135,348
Same Store Sales [Member] | Island Club [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 31, 2000
Location	Oceanside, CA
Year Built	1986
Number of apartment homes | apartment_home	592
Initial Cost, Land	$ 18,027
Initial Cost, Buildings and Improvements	28,654
Costs Capitalized Subsequent to Consolidation	21,829
Land	18,027
Buildings and Improvements	50,483
Total	68,510
Accumulated Depreciation (AD)	(32,842)
Total Cost Net of Accumulated Depreciation	35,668
Encumbrances	$ 93,333
Same Store Sales [Member] | Latrobe [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 31, 2003
Location	Washington, D.C.
Year Built	1980
Number of apartment homes | apartment_home	175
Initial Cost, Land	$ 3,459
Initial Cost, Buildings and Improvements	9,103
Costs Capitalized Subsequent to Consolidation	13,380
Land	3,459
Buildings and Improvements	22,483
Total	25,942
Accumulated Depreciation (AD)	(13,313)
Total Cost Net of Accumulated Depreciation	12,629
Encumbrances	$ 26,128
Same Store Sales [Member] | Laurel Crossing [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 31, 2006
Location	San Mateo, CA
Year Built	1971
Number of apartment homes | apartment_home	418
Initial Cost, Land	$ 49,474
Initial Cost, Buildings and Improvements	17,756
Costs Capitalized Subsequent to Consolidation	15,017
Land	49,474
Buildings and Improvements	32,773
Total	82,247
Accumulated Depreciation (AD)	(17,078)
Total Cost Net of Accumulated Depreciation	65,169
Encumbrances	$ 104,658
Same Store Sales [Member] | Lincoln Place [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 31, 2004
Location	Venice, CA
Year Built	1951
Number of apartment homes | apartment_home	795
Initial Cost, Land	$ 128,332
Initial Cost, Buildings and Improvements	10,439
Costs Capitalized Subsequent to Consolidation	340,136
Land	44,197
Buildings and Improvements	350,575
Total	394,772
Accumulated Depreciation (AD)	(143,166)
Total Cost Net of Accumulated Depreciation	251,606
Encumbrances	$ 184,330
Same Store Sales [Member] | Malibu Canyon [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	Calabasas, CA
Year Built	1986
Number of apartment homes | apartment_home	698
Initial Cost, Land	$ 69,834
Initial Cost, Buildings and Improvements	53,438
Costs Capitalized Subsequent to Consolidation	41,577
Land	69,834
Buildings and Improvements	95,015
Total	164,849
Accumulated Depreciation (AD)	(51,078)
Total Cost Net of Accumulated Depreciation	113,771
Encumbrances	$ 102,968
Same Store Sales [Member] | Mariners Cove [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	San Diego, CA
Year Built	1984
Number of apartment homes | apartment_home	500
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	66,861
Costs Capitalized Subsequent to Consolidation	14,977
Land	0
Buildings and Improvements	81,838
Total	81,838
Accumulated Depreciation (AD)	(42,171)
Total Cost Net of Accumulated Depreciation	39,667
Encumbrances	$ 0
Same Store Sales [Member] | Meadow Creek [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 31, 1994
Location	Boulder, CO
Year Built	1968
Number of apartment homes | apartment_home	332
Initial Cost, Land	$ 1,435
Initial Cost, Buildings and Improvements	24,533
Costs Capitalized Subsequent to Consolidation	10,058
Land	1,435
Buildings and Improvements	34,591
Total	36,026
Accumulated Depreciation (AD)	(21,082)
Total Cost Net of Accumulated Depreciation	14,944
Encumbrances	$ 0
Same Store Sales [Member] | Merrill House [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 31, 2000
Location	Falls Church, VA
Year Built	1964
Number of apartment homes | apartment_home	159
Initial Cost, Land	$ 1,836
Initial Cost, Buildings and Improvements	10,831
Costs Capitalized Subsequent to Consolidation	7,588
Land	1,836
Buildings and Improvements	18,419
Total	20,255
Accumulated Depreciation (AD)	(10,923)
Total Cost Net of Accumulated Depreciation	9,332
Encumbrances	$ 0
Same Store Sales [Member] | Monterey Grove [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jun. 30, 2008
Location	San Jose, CA
Year Built	1999
Number of apartment homes | apartment_home	224
Initial Cost, Land	$ 34,325
Initial Cost, Buildings and Improvements	21,939
Costs Capitalized Subsequent to Consolidation	16,051
Land	34,325
Buildings and Improvements	37,990
Total	72,315
Accumulated Depreciation (AD)	(13,236)
Total Cost Net of Accumulated Depreciation	59,079
Encumbrances	$ 49,680
Same Store Sales [Member] | Ocean House on Prospect [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Apr. 30, 2013
Location	La Jolla, CA
Year Built	1970
Number of apartment homes | apartment_home	53
Initial Cost, Land	$ 12,528
Initial Cost, Buildings and Improvements	18,805
Costs Capitalized Subsequent to Consolidation	15,336
Land	12,528
Buildings and Improvements	34,141
Total	46,669
Accumulated Depreciation (AD)	(8,635)
Total Cost Net of Accumulated Depreciation	38,034
Encumbrances	$ 12,281
Same Store Sales [Member] | One Canal [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 30, 2013
Location	Boston, MA
Year Built	2016
Number of apartment homes | apartment_home	310
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	15,873
Costs Capitalized Subsequent to Consolidation	178,772
Land	0
Buildings and Improvements	194,645
Total	194,645
Accumulated Depreciation (AD)	(29,058)
Total Cost Net of Accumulated Depreciation	165,587
Encumbrances	$ 108,491
Same Store Sales [Member] | Pacific Bay Vistas [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2001
Location	San Bruno, CA
Year Built	1987
Number of apartment homes | apartment_home	308
Initial Cost, Land	$ 28,694
Initial Cost, Buildings and Improvements	62,460
Costs Capitalized Subsequent to Consolidation	40,698
Land	23,354
Buildings and Improvements	103,158
Total	126,512
Accumulated Depreciation (AD)	(39,188)
Total Cost Net of Accumulated Depreciation	87,324
Encumbrances	$ 104,664
Same Store Sales [Member] | Pacifica Park [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 31, 2006
Location	Pacifica, CA
Year Built	1977
Number of apartment homes | apartment_home	104
Initial Cost, Land	$ 12,970
Initial Cost, Buildings and Improvements	6,579
Costs Capitalized Subsequent to Consolidation	8,815
Land	12,970
Buildings and Improvements	15,394
Total	28,364
Accumulated Depreciation (AD)	(7,517)
Total Cost Net of Accumulated Depreciation	20,847
Encumbrances	$ 28,613
Same Store Sales [Member] | Palazzo at Park La Brea, The [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Feb. 29, 2004
Location	Los Angeles, CA
Year Built	2002
Number of apartment homes | apartment_home	521
Initial Cost, Land	$ 48,362
Initial Cost, Buildings and Improvements	125,464
Costs Capitalized Subsequent to Consolidation	48,103
Land	48,362
Buildings and Improvements	173,567
Total	221,929
Accumulated Depreciation (AD)	(87,785)
Total Cost Net of Accumulated Depreciation	134,144
Encumbrances	$ 165,344
Same Store Sales [Member] | Palazzo East at Park La Brea, The [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Mar. 31, 2005
Location	Los Angeles, CA
Year Built	2005
Number of apartment homes | apartment_home	611
Initial Cost, Land	$ 72,578
Initial Cost, Buildings and Improvements	136,503
Costs Capitalized Subsequent to Consolidation	28,065
Land	72,578
Buildings and Improvements	164,568
Total	237,146
Accumulated Depreciation (AD)	(79,668)
Total Cost Net of Accumulated Depreciation	157,478
Encumbrances	$ 192,083
Same Store Sales [Member] | Pathfinder Village [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 31, 2006
Location	Fremont, CA
Year Built	1973
Number of apartment homes | apartment_home	246
Initial Cost, Land	$ 19,595
Initial Cost, Buildings and Improvements	14,838
Costs Capitalized Subsequent to Consolidation	20,707
Land	19,595
Buildings and Improvements	35,545
Total	55,140
Accumulated Depreciation (AD)	(17,480)
Total Cost Net of Accumulated Depreciation	37,660
Encumbrances	$ 55,000
Same Store Sales [Member] | Peachtree Park [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 31, 1996
Location	Atlanta, GA
Year Built	1969
Number of apartment homes | apartment_home	303
Initial Cost, Land	$ 4,684
Initial Cost, Buildings and Improvements	11,713
Costs Capitalized Subsequent to Consolidation	14,244
Land	4,684
Buildings and Improvements	25,957
Total	30,641
Accumulated Depreciation (AD)	(17,244)
Total Cost Net of Accumulated Depreciation	13,397
Encumbrances	$ 27,316
Same Store Sales [Member] | Plantation Gardens [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 31, 1999
Location	Plantation, FL
Year Built	1971
Number of apartment homes | apartment_home	372
Initial Cost, Land	$ 3,773
Initial Cost, Buildings and Improvements	19,443
Costs Capitalized Subsequent to Consolidation	25,547
Land	3,773
Buildings and Improvements	44,990
Total	48,763
Accumulated Depreciation (AD)	(28,766)
Total Cost Net of Accumulated Depreciation	19,997
Encumbrances	$ 0
Same Store Sales [Member] | Preserve at Marin [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Aug. 31, 2011
Location	Corte Madera, CA
Year Built	1964
Number of apartment homes | apartment_home	126
Initial Cost, Land	$ 13,516
Initial Cost, Buildings and Improvements	30,132
Costs Capitalized Subsequent to Consolidation	82,512
Land	13,516
Buildings and Improvements	112,644
Total	126,160
Accumulated Depreciation (AD)	(32,015)
Total Cost Net of Accumulated Depreciation	94,145
Encumbrances	$ 35,451
Same Store Sales [Member] | Ravensworth Towers [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jun. 30, 2004
Location	Annandale, VA
Year Built	1974
Number of apartment homes | apartment_home	219
Initial Cost, Land	$ 3,455
Initial Cost, Buildings and Improvements	17,157
Costs Capitalized Subsequent to Consolidation	4,575
Land	3,455
Buildings and Improvements	21,732
Total	25,187
Accumulated Depreciation (AD)	(15,171)
Total Cost Net of Accumulated Depreciation	10,016
Encumbrances	$ 19,870
Same Store Sales [Member] | River Club,The [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Apr. 30, 2005
Location	Edgewater, NJ
Year Built	1998
Number of apartment homes | apartment_home	266
Initial Cost, Land	$ 30,579
Initial Cost, Buildings and Improvements	30,638
Costs Capitalized Subsequent to Consolidation	8,468
Land	30,579
Buildings and Improvements	39,106
Total	69,685
Accumulated Depreciation (AD)	(19,159)
Total Cost Net of Accumulated Depreciation	50,526
Encumbrances	$ 59,070
Same Store Sales [Member] | Riverloft [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Oct. 31, 1999
Location	Philadelphia, PA
Year Built	1910
Number of apartment homes | apartment_home	184
Initial Cost, Land	$ 2,120
Initial Cost, Buildings and Improvements	11,286
Costs Capitalized Subsequent to Consolidation	38,090
Land	2,120
Buildings and Improvements	49,376
Total	51,496
Accumulated Depreciation (AD)	(25,765)
Total Cost Net of Accumulated Depreciation	25,731
Encumbrances	$ 5,881
Same Store Sales [Member] | Rosewood [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	Camarillo, CA
Year Built	1976
Number of apartment homes | apartment_home	152
Initial Cost, Land	$ 12,430
Initial Cost, Buildings and Improvements	8,060
Costs Capitalized Subsequent to Consolidation	6,983
Land	12,430
Buildings and Improvements	15,043
Total	27,473
Accumulated Depreciation (AD)	(7,950)
Total Cost Net of Accumulated Depreciation	19,523
Encumbrances	$ 0
Same Store Sales [Member] | Royal Crest Estates [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2002
Location	Warwick, RI
Year Built	1972
Number of apartment homes | apartment_home	492
Initial Cost, Land	$ 22,433
Initial Cost, Buildings and Improvements	24,095
Costs Capitalized Subsequent to Consolidation	6,736
Land	22,433
Buildings and Improvements	30,831
Total	53,264
Accumulated Depreciation (AD)	(21,454)
Total Cost Net of Accumulated Depreciation	31,810
Encumbrances	$ 0
Same Store Sales [Member] | Royal Crest Estates [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2002
Location	Nashua, NH
Year Built	1970
Number of apartment homes | apartment_home	902
Initial Cost, Land	$ 68,230
Initial Cost, Buildings and Improvements	45,562
Costs Capitalized Subsequent to Consolidation	16,865
Land	68,230
Buildings and Improvements	62,427
Total	130,657
Accumulated Depreciation (AD)	(44,966)
Total Cost Net of Accumulated Depreciation	85,691
Encumbrances	$ 70,299
Same Store Sales [Member] | Royal Crest Estates [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2002
Location	Marlborough, MA
Year Built	1970
Number of apartment homes | apartment_home	473
Initial Cost, Land	$ 25,178
Initial Cost, Buildings and Improvements	28,786
Costs Capitalized Subsequent to Consolidation	15,100
Land	25,178
Buildings and Improvements	43,886
Total	69,064
Accumulated Depreciation (AD)	(29,314)
Total Cost Net of Accumulated Depreciation	39,750
Encumbrances	$ 62,074
Same Store Sales [Member] | Royal Crest Estates [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2002
Location	North Andover, MA
Year Built	1970
Number of apartment homes | apartment_home	588
Initial Cost, Land	$ 51,292
Initial Cost, Buildings and Improvements	36,808
Costs Capitalized Subsequent to Consolidation	30,314
Land	51,292
Buildings and Improvements	67,122
Total	118,414
Accumulated Depreciation (AD)	(39,455)
Total Cost Net of Accumulated Depreciation	78,959
Encumbrances	$ 81,363
Same Store Sales [Member] | Saybrook Point [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Dec. 31, 2014
Location	San Jose, CA
Year Built	1995
Number of apartment homes | apartment_home	324
Initial Cost, Land	$ 32,842
Initial Cost, Buildings and Improvements	84,457
Costs Capitalized Subsequent to Consolidation	25,960
Land	32,842
Buildings and Improvements	110,417
Total	143,259
Accumulated Depreciation (AD)	(19,010)
Total Cost Net of Accumulated Depreciation	124,249
Encumbrances	$ 61,073
Same Store Sales [Member] | Shenandoah Crossing [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Sep. 30, 2000
Location	Fairfax, VA
Year Built	1984
Number of apartment homes | apartment_home	640
Initial Cost, Land	$ 18,200
Initial Cost, Buildings and Improvements	57,198
Costs Capitalized Subsequent to Consolidation	26,395
Land	18,200
Buildings and Improvements	83,593
Total	101,793
Accumulated Depreciation (AD)	(62,964)
Total Cost Net of Accumulated Depreciation	38,829
Encumbrances	$ 57,204
Same Store Sales [Member] | Springwoods at Lake Ridge [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 31, 2002
Location	Woodbridge, VA
Year Built	1984
Number of apartment homes | apartment_home	180
Initial Cost, Land	$ 5,587
Initial Cost, Buildings and Improvements	7,284
Costs Capitalized Subsequent to Consolidation	3,790
Land	5,587
Buildings and Improvements	11,074
Total	16,661
Accumulated Depreciation (AD)	(5,064)
Total Cost Net of Accumulated Depreciation	11,597
Encumbrances	$ 0
Same Store Sales [Member] | Sterling Apartment Homes, The [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 31, 1999
Location	Philadelphia, PA
Year Built	1961
Number of apartment homes | apartment_home	534
Initial Cost, Land	$ 8,871
Initial Cost, Buildings and Improvements	55,365
Costs Capitalized Subsequent to Consolidation	118,250
Land	8,871
Buildings and Improvements	173,615
Total	182,486
Accumulated Depreciation (AD)	(91,452)
Total Cost Net of Accumulated Depreciation	91,034
Encumbrances	$ 141,077
Same Store Sales [Member] | Stone Creek Club [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Sep. 30, 2000
Location	Germantown, MD
Year Built	1984
Number of apartment homes | apartment_home	240
Initial Cost, Land	$ 13,593
Initial Cost, Buildings and Improvements	9,347
Costs Capitalized Subsequent to Consolidation	8,450
Land	13,593
Buildings and Improvements	17,797
Total	31,390
Accumulated Depreciation (AD)	(13,092)
Total Cost Net of Accumulated Depreciation	18,298
Encumbrances	$ 0
Same Store Sales [Member] | Township At Highlands [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Town Home
Date Consolidated	Nov. 30, 1996
Location	Centennial, CO
Year Built	1985
Number of apartment homes | apartment_home	161
Initial Cost, Land	$ 1,536
Initial Cost, Buildings and Improvements	9,773
Costs Capitalized Subsequent to Consolidation	10,121
Land	1,536
Buildings and Improvements	19,894
Total	21,430
Accumulated Depreciation (AD)	(13,167)
Total Cost Net of Accumulated Depreciation	8,263
Encumbrances	$ 13,120
Same Store Sales [Member] | Vantage Pointe [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Aug. 31, 2002
Location	Swampscott, MA
Year Built	1987
Number of apartment homes | apartment_home	96
Initial Cost, Land	$ 4,748
Initial Cost, Buildings and Improvements	10,089
Costs Capitalized Subsequent to Consolidation	2,661
Land	4,748
Buildings and Improvements	12,750
Total	17,498
Accumulated Depreciation (AD)	(5,806)
Total Cost Net of Accumulated Depreciation	11,692
Encumbrances	$ 0
Same Store Sales [Member] | Villa Del Sol [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	Norwalk, CA
Year Built	1972
Number of apartment homes | apartment_home	120
Initial Cost, Land	$ 7,476
Initial Cost, Buildings and Improvements	4,861
Costs Capitalized Subsequent to Consolidation	5,050
Land	7,476
Buildings and Improvements	9,911
Total	17,387
Accumulated Depreciation (AD)	(6,000)
Total Cost Net of Accumulated Depreciation	11,387
Encumbrances	$ 10,338
Same Store Sales [Member] | Villas of Pasadena [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Jan. 31, 2006
Location	Pasadena, CA
Year Built	1973
Number of apartment homes | apartment_home	92
Initial Cost, Land	$ 9,693
Initial Cost, Buildings and Improvements	6,818
Costs Capitalized Subsequent to Consolidation	4,696
Land	9,693
Buildings and Improvements	11,514
Total	21,207
Accumulated Depreciation (AD)	(5,230)
Total Cost Net of Accumulated Depreciation	15,977
Encumbrances	$ 0
Same Store Sales [Member] | Vivo [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jun. 30, 2016
Location	Cambridge, MA
Year Built	2015
Number of apartment homes | apartment_home	91
Initial Cost, Land	$ 6,450
Initial Cost, Buildings and Improvements	35,974
Costs Capitalized Subsequent to Consolidation	5,851
Land	6,450
Buildings and Improvements	41,825
Total	48,275
Accumulated Depreciation (AD)	(11,588)
Total Cost Net of Accumulated Depreciation	36,687
Encumbrances	$ 19,810
Same Store Sales [Member] | Waterford Village [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2002
Location	Bridgewater, MA
Year Built	1971
Number of apartment homes | apartment_home	588
Initial Cost, Land	$ 29,110
Initial Cost, Buildings and Improvements	28,101
Costs Capitalized Subsequent to Consolidation	11,636
Land	29,110
Buildings and Improvements	39,737
Total	68,847
Accumulated Depreciation (AD)	(29,186)
Total Cost Net of Accumulated Depreciation	39,661
Encumbrances	$ 34,464
Same Store Sales [Member] | Waterways Village [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jun. 30, 1997
Location	Aventura, FL
Year Built	1994
Number of apartment homes | apartment_home	180
Initial Cost, Land	$ 4,504
Initial Cost, Buildings and Improvements	11,064
Costs Capitalized Subsequent to Consolidation	16,910
Land	4,504
Buildings and Improvements	27,974
Total	32,478
Accumulated Depreciation (AD)	(13,996)
Total Cost Net of Accumulated Depreciation	18,482
Encumbrances	$ 12,865
Same Store Sales [Member] | Waverly Apartments [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2008
Location	Brighton, MA
Year Built	1970
Number of apartment homes | apartment_home	103
Initial Cost, Land	$ 7,920
Initial Cost, Buildings and Improvements	11,347
Costs Capitalized Subsequent to Consolidation	6,844
Land	7,920
Buildings and Improvements	18,191
Total	26,111
Accumulated Depreciation (AD)	(7,441)
Total Cost Net of Accumulated Depreciation	18,670
Encumbrances	$ 11,245
Same Store Sales [Member] | Wexford Village [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 31, 2002
Location	Worcester, MA
Year Built	1974
Number of apartment homes | apartment_home	264
Initial Cost, Land	$ 6,349
Initial Cost, Buildings and Improvements	17,939
Costs Capitalized Subsequent to Consolidation	5,183
Land	6,349
Buildings and Improvements	23,122
Total	29,471
Accumulated Depreciation (AD)	(14,281)
Total Cost Net of Accumulated Depreciation	15,190
Encumbrances	$ 0
Same Store Sales [Member] | Willow Bend [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	May 31, 1998
Location	Rolling Meadows, IL
Year Built	1969
Number of apartment homes | apartment_home	328
Initial Cost, Land	$ 2,717
Initial Cost, Buildings and Improvements	15,437
Costs Capitalized Subsequent to Consolidation	20,130
Land	2,717
Buildings and Improvements	35,567
Total	38,284
Accumulated Depreciation (AD)	(24,855)
Total Cost Net of Accumulated Depreciation	13,429
Encumbrances	$ 32,489
Same Store Sales [Member] | Windrift [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2001
Location	Oceanside, CA
Year Built	1987
Number of apartment homes | apartment_home	404
Initial Cost, Land	$ 24,960
Initial Cost, Buildings and Improvements	17,590
Costs Capitalized Subsequent to Consolidation	22,254
Land	24,960
Buildings and Improvements	39,844
Total	64,804
Accumulated Depreciation (AD)	(26,130)
Total Cost Net of Accumulated Depreciation	38,674
Encumbrances	$ 72,646
Same Store Sales [Member] | Windsor Park [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2001
Location	Woodbridge, VA
Year Built	1987
Number of apartment homes | apartment_home	220
Initial Cost, Land	$ 4,279
Initial Cost, Buildings and Improvements	15,970
Costs Capitalized Subsequent to Consolidation	6,366
Land	4,279
Buildings and Improvements	22,336
Total	26,615
Accumulated Depreciation (AD)	(14,287)
Total Cost Net of Accumulated Depreciation	12,328
Encumbrances	$ 0
Same Store Sales [Member] | Yacht Club at Brickell [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 31, 2003
Location	Miami, FL
Year Built	1998
Number of apartment homes | apartment_home	357
Initial Cost, Land	$ 31,362
Initial Cost, Buildings and Improvements	32,214
Costs Capitalized Subsequent to Consolidation	18,825
Land	31,362
Buildings and Improvements	51,039
Total	82,401
Accumulated Depreciation (AD)	(19,678)
Total Cost Net of Accumulated Depreciation	62,723
Encumbrances	$ 68,351
Same Store Sales [Member] | Yorktown Apartments [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 31, 1999
Location	Lombard, IL
Year Built	1971
Number of apartment homes | apartment_home	292
Initial Cost, Land	$ 2,413
Initial Cost, Buildings and Improvements	10,374
Costs Capitalized Subsequent to Consolidation	53,236
Land	2,413
Buildings and Improvements	63,610
Total	66,023
Accumulated Depreciation (AD)	(31,274)
Total Cost Net of Accumulated Depreciation	34,749
Encumbrances	$ 30,167
Redevelopment and Development [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes | apartment_home	3,143
Initial Cost, Land	$ 123,371
Initial Cost, Buildings and Improvements	197,650
Costs Capitalized Subsequent to Consolidation	1,026,681
Land	123,371
Buildings and Improvements	1,224,331
Total	1,347,702
Accumulated Depreciation (AD)	(410,517)
Total Cost Net of Accumulated Depreciation	937,185
Encumbrances	$ 332,917
Redevelopment and Development [Member] | 236-238 East 88th Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 31, 2004
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	42
Initial Cost, Land	$ 8,820
Initial Cost, Buildings and Improvements	2,914
Costs Capitalized Subsequent to Consolidation	8,734
Land	8,820
Buildings and Improvements	11,648
Total	20,468
Accumulated Depreciation (AD)	(2,088)
Total Cost Net of Accumulated Depreciation	18,380
Encumbrances	$ 0
Redevelopment and Development [Member] | 707 Leahy [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Apr. 30, 2007
Location	Redwood City, CA
Year Built	1973
Number of apartment homes | apartment_home	110
Initial Cost, Land	$ 15,444
Initial Cost, Buildings and Improvements	7,909
Costs Capitalized Subsequent to Consolidation	16,619
Land	15,444
Buildings and Improvements	24,528
Total	39,972
Accumulated Depreciation (AD)	(6,731)
Total Cost Net of Accumulated Depreciation	33,241
Encumbrances	$ 8,534
Redevelopment and Development [Member] | Bay Parc Plaza [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 30, 2004
Location	Miami, FL
Year Built	2000
Number of apartment homes | apartment_home	474
Initial Cost, Land	$ 22,680
Initial Cost, Buildings and Improvements	41,847
Costs Capitalized Subsequent to Consolidation	38,851
Land	22,680
Buildings and Improvements	80,698
Total	103,378
Accumulated Depreciation (AD)	(26,606)
Total Cost Net of Accumulated Depreciation	76,772
Encumbrances	$ 76,631
Redevelopment and Development [Member] | Flamingo Point [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 30, 1997
Location	Miami Beach, FL
Year Built	1960
Number of apartment homes | apartment_home	1,101
Initial Cost, Land	$ 32,427
Initial Cost, Buildings and Improvements	48,808
Costs Capitalized Subsequent to Consolidation	400,164
Land	32,427
Buildings and Improvements	448,972
Total	481,399
Accumulated Depreciation (AD)	(188,572)
Total Cost Net of Accumulated Depreciation	292,827
Encumbrances	$ 0
Redevelopment and Development [Member] | Parc Mosaic [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Dec. 31, 2014
Location	Boulder, CO
Year Built	1970
Number of apartment homes | apartment_home	226
Initial Cost, Land	$ 15,300
Initial Cost, Buildings and Improvements	0
Costs Capitalized Subsequent to Consolidation	107,179
Land	15,300
Buildings and Improvements	107,179
Total	122,479
Accumulated Depreciation (AD)	(461)
Total Cost Net of Accumulated Depreciation	122,018
Encumbrances	$ 0
Redevelopment and Development [Member] | Park Towne Place [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Apr. 30, 2000
Location	Philadelphia, PA
Year Built	1959
Number of apartment homes | apartment_home	940
Initial Cost, Land	$ 10,472
Initial Cost, Buildings and Improvements	47,301
Costs Capitalized Subsequent to Consolidation	353,053
Land	10,472
Buildings and Improvements	400,354
Total	410,826
Accumulated Depreciation (AD)	(152,223)
Total Cost Net of Accumulated Depreciation	258,603
Encumbrances	$ 196,655
Redevelopment and Development [Member] | Villas at Park La Brea, The [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 31, 2002
Location	Los Angeles, CA
Year Built	2002
Number of apartment homes | apartment_home	250
Initial Cost, Land	$ 8,630
Initial Cost, Buildings and Improvements	48,871
Costs Capitalized Subsequent to Consolidation	19,251
Land	8,630
Buildings and Improvements	68,122
Total	76,752
Accumulated Depreciation (AD)	(33,834)
Total Cost Net of Accumulated Depreciation	42,918
Encumbrances	$ 51,097
Redevelopment and Development [Member] | Other [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes | apartment_home	0
Initial Cost, Land	$ 9,598
Initial Cost, Buildings and Improvements	0
Costs Capitalized Subsequent to Consolidation	82,830
Land	9,598
Buildings and Improvements	82,830
Total	92,428
Accumulated Depreciation (AD)	(2)
Total Cost Net of Accumulated Depreciation	92,426
Encumbrances	$ 0
Acquisition [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes | apartment_home	1,590
Initial Cost, Land	$ 82,017
Initial Cost, Buildings and Improvements	486,330
Costs Capitalized Subsequent to Consolidation	59,515
Land	82,017
Buildings and Improvements	545,845
Total	627,862
Accumulated Depreciation (AD)	(30,104)
Total Cost Net of Accumulated Depreciation	597,758
Encumbrances	$ 232,827
Acquisition [Member] | 777 South Broad Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	May 31, 2018
Location	Philadelphia, PA
Year Built	2010
Number of apartment homes | apartment_home	146
Initial Cost, Land	$ 6,986
Initial Cost, Buildings and Improvements	67,512
Costs Capitalized Subsequent to Consolidation	2,596
Land	6,986
Buildings and Improvements	70,108
Total	77,094
Accumulated Depreciation (AD)	(4,115)
Total Cost Net of Accumulated Depreciation	72,979
Encumbrances	$ 56,581
Acquisition [Member] | Avery Row [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 31, 2018
Location	Arlington, VA
Year Built	2013
Number of apartment homes | apartment_home	67
Initial Cost, Land	$ 8,165
Initial Cost, Buildings and Improvements	21,348
Costs Capitalized Subsequent to Consolidation	1,812
Land	8,165
Buildings and Improvements	23,160
Total	31,325
Accumulated Depreciation (AD)	(913)
Total Cost Net of Accumulated Depreciation	30,412
Encumbrances	$ 0
Acquisition [Member] | Bent Tree Apartments [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Feb. 28, 2018
Location	Centreville, VA
Year Built	1986
Number of apartment homes | apartment_home	748
Initial Cost, Land	$ 46,975
Initial Cost, Buildings and Improvements	113,695
Costs Capitalized Subsequent to Consolidation	20,823
Land	46,975
Buildings and Improvements	134,518
Total	181,493
Accumulated Depreciation (AD)	(9,679)
Total Cost Net of Accumulated Depreciation	171,814
Encumbrances	$ 0
Acquisition [Member] | Locust on the Park [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	May 31, 2018
Location	Philadelphia, PA
Year Built	1911
Number of apartment homes | apartment_home	152
Initial Cost, Land	$ 5,292
Initial Cost, Buildings and Improvements	53,823
Costs Capitalized Subsequent to Consolidation	4,228
Land	5,292
Buildings and Improvements	58,051
Total	63,343
Accumulated Depreciation (AD)	(3,510)
Total Cost Net of Accumulated Depreciation	59,833
Encumbrances	$ 34,891
Acquisition [Member] | One Ardmore
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Apr. 30, 2019
Location	Ardmore, PA
Year Built	2019
Number of apartment homes | apartment_home	110
Initial Cost, Land	$ 4,929
Initial Cost, Buildings and Improvements	61,631
Costs Capitalized Subsequent to Consolidation	1,387
Land	4,929
Buildings and Improvements	63,018
Total	67,947
Accumulated Depreciation (AD)	(1,560)
Total Cost Net of Accumulated Depreciation	66,387
Encumbrances	$ 31,052
Acquisition [Member] | SouthStar Lofts [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	May 31, 2018
Location	Philadelphia, PA
Year Built	2014
Number of apartment homes | apartment_home	85
Initial Cost, Land	$ 1,780
Initial Cost, Buildings and Improvements	37,428
Costs Capitalized Subsequent to Consolidation	683
Land	1,780
Buildings and Improvements	38,111
Total	39,891
Accumulated Depreciation (AD)	(2,235)
Total Cost Net of Accumulated Depreciation	37,656
Encumbrances	$ 29,624
Acquisition [Member] | The Left Bank [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	May 31, 2018
Location	Philadelphia, PA
Year Built	1929
Number of apartment homes | apartment_home	282
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	130,893
Costs Capitalized Subsequent to Consolidation	13,352
Land	0
Buildings and Improvements	144,245
Total	144,245
Accumulated Depreciation (AD)	(8,092)
Total Cost Net of Accumulated Depreciation	136,153
Encumbrances	$ 80,679
Acquisition [Member] | Other [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes | apartment_home	0
Initial Cost, Land	$ 7,890
Initial Cost, Buildings and Improvements	0
Costs Capitalized Subsequent to Consolidation	14,634
Land	7,890
Buildings and Improvements	14,634
Total	22,524
Accumulated Depreciation (AD)	0
Total Cost Net of Accumulated Depreciation	22,524
Encumbrances	$ 0
Other Real Estate [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes | apartment_home	1,315
Initial Cost, Land	$ 341,516
Initial Cost, Buildings and Improvements	281,186
Costs Capitalized Subsequent to Consolidation	70,610
Land	341,516
Buildings and Improvements	351,796
Total	693,312
Accumulated Depreciation (AD)	(89,488)
Total Cost Net of Accumulated Depreciation	603,824
Encumbrances	$ 106,119
Other Real Estate [Member] | 1001 Brickell [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jul. 31, 2019
Location	Miami, FL
Year Built	1985
Number of apartment homes | apartment_home	0
Initial Cost, Land	$ 149,519
Initial Cost, Buildings and Improvements	152,892
Costs Capitalized Subsequent to Consolidation	5,228
Land	149,519
Buildings and Improvements	158,120
Total	307,639
Accumulated Depreciation (AD)	(8,053)
Total Cost Net of Accumulated Depreciation	299,586
Encumbrances	$ 0
Other Real Estate [Member] | 173 E. 90th Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	May 31, 2004
Location	New York, NY
Year Built	1910
Number of apartment homes | apartment_home	72
Initial Cost, Land	$ 12,066
Initial Cost, Buildings and Improvements	4,535
Costs Capitalized Subsequent to Consolidation	8,827
Land	12,066
Buildings and Improvements	13,362
Total	25,428
Accumulated Depreciation (AD)	(4,667)
Total Cost Net of Accumulated Depreciation	20,761
Encumbrances	$ 0
Other Real Estate [Member] | 182-188 Columbus Avenue [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Feb. 28, 2007
Location	New York, NY
Year Built	1910
Number of apartment homes | apartment_home	32
Initial Cost, Land	$ 19,123
Initial Cost, Buildings and Improvements	3,300
Costs Capitalized Subsequent to Consolidation	5,769
Land	19,123
Buildings and Improvements	9,069
Total	28,192
Accumulated Depreciation (AD)	(4,603)
Total Cost Net of Accumulated Depreciation	23,589
Encumbrances	$ 13,635
Other Real Estate [Member] | 234 East 88th Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Jan. 31, 2014
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	20
Initial Cost, Land	$ 2,448
Initial Cost, Buildings and Improvements	4,449
Costs Capitalized Subsequent to Consolidation	828
Land	2,448
Buildings and Improvements	5,277
Total	7,725
Accumulated Depreciation (AD)	(1,418)
Total Cost Net of Accumulated Depreciation	6,307
Encumbrances	$ 0
Other Real Estate [Member] | 237-239 Ninth Avenue [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 31, 2005
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	36
Initial Cost, Land	$ 8,495
Initial Cost, Buildings and Improvements	1,866
Costs Capitalized Subsequent to Consolidation	3,132
Land	8,495
Buildings and Improvements	4,998
Total	13,493
Accumulated Depreciation (AD)	(3,166)
Total Cost Net of Accumulated Depreciation	10,327
Encumbrances	$ 5,438
Other Real Estate [Member] | 240 West 73rd Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 30, 2004
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	200
Initial Cost, Land	$ 68,109
Initial Cost, Buildings and Improvements	12,140
Costs Capitalized Subsequent to Consolidation	14,048
Land	68,109
Buildings and Improvements	26,188
Total	94,297
Accumulated Depreciation (AD)	(10,715)
Total Cost Net of Accumulated Depreciation	83,582
Encumbrances	$ 0
Other Real Estate [Member] | 311 & 313 East 73rd Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Mar. 31, 2003
Location	New York, NY
Year Built	1904
Number of apartment homes | apartment_home	34
Initial Cost, Land	$ 5,678
Initial Cost, Buildings and Improvements	1,609
Costs Capitalized Subsequent to Consolidation	598
Land	5,678
Buildings and Improvements	2,207
Total	7,885
Accumulated Depreciation (AD)	(1,625)
Total Cost Net of Accumulated Depreciation	6,260
Encumbrances	$ 0
Other Real Estate [Member] | 464-466 Amsterdam & 200-210 [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Feb. 28, 2007
Location	New York, NY
Year Built	1910
Number of apartment homes | apartment_home	71
Initial Cost, Land	$ 25,553
Initial Cost, Buildings and Improvements	7,101
Costs Capitalized Subsequent to Consolidation	9,153
Land	25,553
Buildings and Improvements	16,254
Total	41,807
Accumulated Depreciation (AD)	(6,396)
Total Cost Net of Accumulated Depreciation	35,411
Encumbrances	$ 20,094
Other Real Estate [Member] | 518 East 88th Street [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Jan. 31, 2014
Location	New York, NY
Year Built	1900
Number of apartment homes | apartment_home	20
Initial Cost, Land	$ 2,233
Initial Cost, Buildings and Improvements	4,315
Costs Capitalized Subsequent to Consolidation	625
Land	2,233
Buildings and Improvements	4,940
Total	7,173
Accumulated Depreciation (AD)	(1,388)
Total Cost Net of Accumulated Depreciation	5,785
Encumbrances	$ 0
Other Real Estate [Member] | Columbus Avenue [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Sep. 30, 2003
Location	New York, NY
Year Built	1880
Number of apartment homes | apartment_home	59
Initial Cost, Land	$ 35,527
Initial Cost, Buildings and Improvements	9,450
Costs Capitalized Subsequent to Consolidation	9,327
Land	35,527
Buildings and Improvements	18,777
Total	54,304
Accumulated Depreciation (AD)	(12,118)
Total Cost Net of Accumulated Depreciation	42,186
Encumbrances	$ 24,608
Other Real Estate [Member] | Heritage Park Escondido [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 31, 2000
Location	Escondido, CA
Year Built	1986
Number of apartment homes | apartment_home	196
Initial Cost, Land	$ 1,055
Initial Cost, Buildings and Improvements	7,565
Costs Capitalized Subsequent to Consolidation	2,945
Land	1,055
Buildings and Improvements	10,510
Total	11,565
Accumulated Depreciation (AD)	(7,188)
Total Cost Net of Accumulated Depreciation	4,377
Encumbrances	$ 5,867
Other Real Estate [Member] | Heritage Park Livermore [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 31, 2000
Location	Livermore, CA
Year Built	1988
Number of apartment homes | apartment_home	167
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	10,209
Costs Capitalized Subsequent to Consolidation	2,111
Land	0
Buildings and Improvements	12,320
Total	12,320
Accumulated Depreciation (AD)	(8,576)
Total Cost Net of Accumulated Depreciation	3,744
Encumbrances	$ 6,090
Other Real Estate [Member] | Heritage Village Anaheim [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 31, 2000
Location	Anaheim, CA
Year Built	1986
Number of apartment homes | apartment_home	196
Initial Cost, Land	$ 1,832
Initial Cost, Buildings and Improvements	8,541
Costs Capitalized Subsequent to Consolidation	2,332
Land	1,832
Buildings and Improvements	10,873
Total	12,705
Accumulated Depreciation (AD)	(7,339)
Total Cost Net of Accumulated Depreciation	5,366
Encumbrances	$ 7,124
Other Real Estate [Member] | Mezzo [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 31, 2015
Location	Atlanta, GA
Year Built	2008
Number of apartment homes | apartment_home	94
Initial Cost, Land	$ 4,292
Initial Cost, Buildings and Improvements	34,178
Costs Capitalized Subsequent to Consolidation	1,817
Land	4,292
Buildings and Improvements	35,995
Total	40,287
Accumulated Depreciation (AD)	(6,918)
Total Cost Net of Accumulated Depreciation	33,369
Encumbrances	$ 22,970
Other Real Estate [Member] | St. George Villas [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 31, 2006
Location	St. George, SC
Year Built	1984
Number of apartment homes | apartment_home	40
Initial Cost, Land	$ 107
Initial Cost, Buildings and Improvements	1,025
Costs Capitalized Subsequent to Consolidation	419
Land	107
Buildings and Improvements	1,444
Total	1,551
Accumulated Depreciation (AD)	(1,290)
Total Cost Net of Accumulated Depreciation	261
Encumbrances	$ 293
Other Real Estate [Member] | Tremont [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 31, 2014
Location	Atlanta, GA
Year Built	2009
Number of apartment homes | apartment_home	78
Initial Cost, Land	$ 5,274
Initial Cost, Buildings and Improvements	18,011
Costs Capitalized Subsequent to Consolidation	3,069
Land	5,274
Buildings and Improvements	21,080
Total	26,354
Accumulated Depreciation (AD)	(4,028)
Total Cost Net of Accumulated Depreciation	22,326
Encumbrances	$ 0
Other Real Estate [Member] | Other Real Estate Other [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment homes | apartment_home	0
Initial Cost, Land	$ 205
Initial Cost, Buildings and Improvements	0
Costs Capitalized Subsequent to Consolidation	382
Land	205
Buildings and Improvements	382
Total	587
Accumulated Depreciation (AD)	0
Total Cost Net of Accumulated Depreciation	587
Encumbrances	$ 0

Schedule III_ Real Estate and_2

Schedule III: Real Estate and Accumulated Depreciation - Schedule of Real Estate and Accumulated Depreciation (Parenthetical) (Details) $ in Billions	12 Months Ended
	Dec. 31, 2019USD ($)
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Aggregate cost of land and depreciable property for federal income tax purposes	$ 3.8
Minimum [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Depreciable life for buildings and improvements	5 years
Maximum [Member]
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Depreciable life for buildings and improvements	30 years

Schedule III_ Real Estate and_3

Schedule III: Real Estate and Accumulated Depreciation - Summary Real Estate and Accumulated Depreciation (Details) - Aimco Real Estate - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total portfolio
Total portfolio balance at beginning of year	$ 8,308,590	$ 8,478,877	$ 8,486,166
Additions during the year:
Acquisitions	383,557	501,009	16,687
Capital additions	404,896	348,727	354,229
Dispositions and other	(359,452)	(1,020,023)	(378,205)
Total portfolio balance at end of year	8,737,591	8,308,590	8,478,877
Accumulated depreciation balance at beginning of year	2,585,115	2,848,609	2,730,758
Depreciation	358,661	354,208	344,960
Dispositions and other	(225,492)	(617,702)	(227,109)
Accumulated depreciation balance at end of year	$ 2,718,284	$ 2,585,115	$ 2,848,609