Apartment Investment and Management (AIV) 10-K 20 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 15, 2019	Jun. 30, 2018
Entity Registrant Name	APARTMENT INVESTMENT & MANAGEMENT CO
Entity Central Index Key	922,864
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		148,766,616
Entity Public Float			$ 6.6
AIMCO PROPERTIES, L.P.
Entity Registrant Name	AIMCO PROPERTIES LP
Entity Central Index Key	926,660
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Amendment Flag	false
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		158,495,487

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
ASSETS
Total assets	$ 6,190,004	$ 6,079,040
LIABILITIES AND EQUITY
Total liabilities	4,325,072	4,321,750
Preferred noncontrolling interests in Aimco Operating Partnership (Note 7)	101,291	101,537
Commitments and contingencies (Note 5)
Equity/Partners' Capital:
Perpetual Preferred Stock (Note 6)	125,000	125,000
Common Stock, $0.01 par value, 500,787,260 shares authorized, 149,133,826 and 157,189,447 shares issued/outstanding at December 31, 2018 and 2017, respectively	1,491	1,572
Additional paid-in capital	3,515,641	3,900,042
Accumulated other comprehensive income	4,794	3,603
Distributions in excess of earnings	(1,947,507)	(2,367,073)
Total Aimco equity	1,699,419	1,663,144
Noncontrolling interests in consolidated real estate partnerships	(2,967)	(1,716)
Common noncontrolling interests in Aimco Operating Partnership	67,189	(5,675)
Total equity	1,763,641	1,655,753
Total liabilities and equity	6,190,004	6,079,040
Asset Management
ASSETS
Net real estate	0	224,873
Cash and cash equivalents	0	16,288
Restricted cash	0	30,928
Other assets	0	15,533
LIABILITIES AND EQUITY
Non-recourse property debt secured by Real Estate communities, net	0	227,141
Accrued liabilities and other	0	19,812
Aimco Real Estate
ASSETS
Buildings and improvements	6,552,065	6,174,149
Land	1,756,525	1,753,604
Total real estate	8,308,590	7,927,753
Accumulated depreciation	(2,585,115)	(2,522,358)
Net real estate	5,723,475	5,405,395
Cash and cash equivalents	36,858	60,498
Restricted cash	35,737	34,827
Other assets	351,541	272,739
Assets held for sale	42,393	17,959
LIABILITIES AND EQUITY
Non-recourse property debt secured by Real Estate communities, net	3,915,305	3,545,109
Term loan, net	0	249,501
Revolving credit facility borrowings	160,360	67,160
Total indebtedness associated with Real Estate portfolio	4,075,665	3,861,770
Accrued liabilities and other	226,230	213,027
Liabilities related to assets held for sale	23,177	0
AIMCO Properties, L.P.
ASSETS
Total assets	6,190,004	6,079,040
LIABILITIES AND EQUITY
Total liabilities	4,325,072	4,321,750
Preferred noncontrolling interests in Aimco Operating Partnership (Note 7)	101,291	101,537
Commitments and contingencies (Note 5)
Equity/Partners' Capital:
Preferred units (Note 7)	125,000	125,000
General Partner and Special Limited Partner	1,574,419	1,538,144
Limited Partners	67,189	(5,675)
Partners’ capital attributable to the Aimco Operating Partnership	1,766,608	1,657,469
Noncontrolling interests in consolidated real estate partnerships	(2,967)	(1,716)
Total partners’ capital	1,763,641	1,655,753
Total liabilities and equity	6,190,004	6,079,040
AIMCO Properties, L.P. | Asset Management
ASSETS
Net real estate	0	224,873
Cash and cash equivalents	0	16,288
Restricted cash	0	30,928
Other assets	0	15,533
LIABILITIES AND EQUITY
Non-recourse property debt secured by Real Estate communities, net	0	227,141
Accrued liabilities and other	0	19,812
AIMCO Properties, L.P. | Aimco Real Estate
ASSETS
Buildings and improvements	6,552,065	6,174,149
Land	1,756,525	1,753,604
Total real estate	8,308,590	7,927,753
Accumulated depreciation	(2,585,115)	(2,522,358)
Net real estate	5,723,475	5,405,395
Cash and cash equivalents	36,858	60,498
Restricted cash	35,737	34,827
Other assets	351,541	272,739
Assets held for sale	42,393	17,959
LIABILITIES AND EQUITY
Non-recourse property debt secured by Real Estate communities, net	3,915,305	3,545,109
Term loan, net	0	249,501
Revolving credit facility borrowings	160,360	67,160
Total indebtedness associated with Real Estate portfolio	4,075,665	3,861,770
Accrued liabilities and other	226,230	213,027
Liabilities related to assets held for sale	$ 23,177	$ 0

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2018	Dec. 31, 2017
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)	149,133,826	157,189,447
Common stock, shares outstanding (in shares)	149,133,826	157,189,447

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
REVENUES:
Tax credit and transaction revenues	$ 6,987	$ 13,243	$ 21,323
Total revenues	972,410	1,005,437	995,854
OPERATING EXPENSES:
Depreciation and amortization	377,786	366,184	333,066
General and administrative expenses	46,268	43,657	46,784
Other expenses, net	3,778	11,148	14,295
Provision for real estate impairment loss	0	35,881	0
Total operating expenses	756,654	811,454	749,058
Interest income	10,914	8,332	7,797
Interest expense	(200,634)	(194,615)	(196,389)
Gain on dispositions of real estate and the Asset Management Business	677,463	300,849	400,156
Other, net	77	7,694	6,071
Income before income tax benefit	703,576	316,243	464,431
Income tax benefit (Note 9)	13,027	30,836	18,842
Net income	716,603	347,079	483,273
Noncontrolling interests:
Net income attributable to noncontrolling interests in consolidated real estate partnerships	(8,220)	(9,084)	(25,256)
Net income attributable to preferred noncontrolling interests in Aimco Operating Partnership	(7,739)	(7,764)	(7,239)
Net income attributable to common noncontrolling interests in Aimco Operating Partnership	(34,417)	(14,457)	(20,368)
Net income attributable to noncontrolling interests	(50,376)	(31,305)	(52,863)
Net income attributable to the company	666,227	315,774	430,410
Net income attributable to the company's preferred equityholders	(8,593)	(8,594)	(11,994)
Net income attributable to participating securities	(1,037)	(319)	(635)
Net income attributable to Aimco common stockholders	$ 656,597	$ 306,861	$ 417,781
Net income attributable to the company per common share/unit - basic (in dollars per share)	$ 4.21	$ 1.96	$ 2.68
Net income attributable to the company per common share/unit - diluted (in dollars per share)	$ 4.21	$ 1.96	$ 2.67
Weighted average common shares/units outstanding - basic (in shares)	155,866	156,323	156,001
Weighted average common shares/units outstanding - diluted (in shares)	156,053	156,796	156,391
Asset Management
REVENUES:
Rental and other property revenues	$ 42,830	$ 74,046	$ 74,640
OPERATING EXPENSES:
Property operating expenses	20,921	35,458	36,956
Aimco Real Estate
REVENUES:
Rental and other property revenues	922,593	918,148	899,891
OPERATING EXPENSES:
Property operating expenses	307,901	319,126	317,957
AIMCO Properties, L.P.
REVENUES:
Tax credit and transaction revenues	6,987	13,243	21,323
Total revenues	972,410	1,005,437	995,854
OPERATING EXPENSES:
Depreciation and amortization	377,786	366,184	333,066
General and administrative expenses	46,268	43,657	46,784
Other expenses, net	3,778	11,148	14,295
Provision for real estate impairment loss	0	35,881	0
Total operating expenses	756,654	811,454	749,058
Interest income	10,914	8,332	7,797
Interest expense	(200,634)	(194,615)	(196,389)
Gain on dispositions of real estate and the Asset Management Business	677,463	300,849	400,156
Other, net	77	7,694	6,071
Income before income tax benefit	703,576	316,243	464,431
Income tax benefit (Note 9)	13,027	30,836	18,842
Net income	716,603	347,079	483,273
Noncontrolling interests:
Net income attributable to noncontrolling interests in consolidated real estate partnerships	(8,220)	(9,084)	(25,256)
Net income attributable to the company	708,383	337,995	458,017
Net income attributable to the company's preferred equityholders	(16,332)	(16,358)	(19,233)
Net income attributable to participating securities	(1,177)	(337)	(635)
Net income attributable to Aimco common stockholders	$ 690,874	$ 321,300	$ 438,149
Net income attributable to the company per common share/unit - basic (in dollars per share)	$ 4.22	$ 1.96	$ 2.68
Net income attributable to the company per common share/unit - diluted (in dollars per share)	$ 4.21	$ 1.96	$ 2.67
Weighted average common shares/units outstanding - basic (in shares)	163,846	163,746	163,761
Weighted average common shares/units outstanding - diluted (in shares)	164,033	164,218	164,151
AIMCO Properties, L.P. | Asset Management
REVENUES:
Rental and other property revenues	$ 42,830	$ 74,046	$ 74,640
OPERATING EXPENSES:
Property operating expenses	20,921	35,458	36,956
AIMCO Properties, L.P. | Aimco Real Estate
REVENUES:
Rental and other property revenues	922,593	918,148	899,891
OPERATING EXPENSES:
Property operating expenses	$ 307,901	$ 319,126	$ 317,957

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income	$ 716,603	$ 347,079	$ 483,273
Other comprehensive gain:
Realized and unrealized (losses) gains on interest rate swaps	0	(173)	221
Losses on interest rate swaps reclassified into earnings from accumulated other comprehensive loss	1,391	1,480	1,586
Unrealized (losses) gains on available for sale debt securities	(131)	1,507	5,855
Other comprehensive gain	1,260	2,814	7,662
Comprehensive income	717,863	349,893	490,935
Comprehensive income attributable to noncontrolling interests	(50,445)	(31,527)	(53,474)
Comprehensive income attributable to Aimco/Operating Partnership	667,418	318,366	437,461
AIMCO Properties, L.P.
Net income	716,603	347,079	483,273
Other comprehensive gain:
Realized and unrealized (losses) gains on interest rate swaps	0	(173)	221
Losses on interest rate swaps reclassified into earnings from accumulated other comprehensive loss	1,391	1,480	1,586
Unrealized (losses) gains on available for sale debt securities	(131)	1,507	5,855
Other comprehensive gain	1,260	2,814	7,662
Comprehensive income	717,863	349,893	490,935
Comprehensive income attributable to noncontrolling interests	(8,220)	(9,185)	(25,516)
Comprehensive income attributable to Aimco/Operating Partnership	$ 709,643	$ 340,708	$ 465,419

Consolidated Statements of Equi

Consolidated Statements of Equity - USD ($) shares in Thousands, $ in Thousands	Total	Total Aimco Equity	Preferred Stock	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Distributions in Excess of Earnings	Noncontrolling Interests
Balances (in shares) at Dec. 31, 2015			6,391	156,326
Balances at Dec. 31, 2015	$ 1,763,905	$ 1,622,391	$ 159,126	$ 1,563	$ 4,064,659	$ (6,040)	$ (2,596,917)	$ 141,514
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption and repurchase of stock (in shares)			(1,391)
Redemption and repurchase of stock	(34,799)	(34,799)	$ (34,126)		1,307		(1,980)
Redemption of Aimco Operating Partnership units	(10,819)							(10,819)
Amortization of share-based compensation cost (in shares)				31
Amortization of share-based compensation cost	8,610	8,610			8,610
Effect of changes in ownership for consolidated entities	(16,064)	(26,171)			(26,171)			10,107
Change in accumulated other comprehensive income	7,662	7,051				7,051		611
Other, net (in shares)				531
Other, net	3,323	3,323		$ 6	3,317		0
Net income	476,034	430,410					430,410	45,624
Distributions to noncontrolling interests	(35,974)							(35,974)
Common Stock dividends	(206,898)	(206,898)					(206,898)
Preferred Stock dividends	(10,014)	(10,014)					(10,014)
Balances (in shares) at Dec. 31, 2016			5,000	156,888
Balances at Dec. 31, 2016	1,944,966	1,793,903	$ 125,000	$ 1,569	4,051,722	1,011	(2,385,399)	151,063
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption of Aimco Operating Partnership units	(11,882)							(11,882)
Amortization of share-based compensation cost (in shares)				18
Amortization of share-based compensation cost	9,251	8,638			8,638			613
Contributions from noncontrolling interests	3,401							3,401
Effect of changes in ownership for consolidated entities	(312,775)	(160,586)			(160,586)			(152,189)
Change in accumulated other comprehensive income	2,814	2,592				2,592		222
Other, net (in shares)				283
Other, net	271	271		$ 3	268
Net income	339,315	315,774					315,774	23,541
Distributions to noncontrolling interests	(19,132)							(19,132)
Common Stock dividends	(226,172)	(226,172)					(226,172)
Preferred Stock dividends	(8,594)	(8,594)					(8,594)
Balances (in shares) at Dec. 31, 2017			5,000	157,189
Balances at Dec. 31, 2017	1,655,753	1,663,144	$ 125,000	$ 1,572	3,900,042	3,603	(2,367,073)	(7,391)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemption and repurchase of stock (in shares)				(8,219)
Redemption and repurchase of stock	(373,593)	(373,593)		$ (82)	(373,511)
Issuance of Aimco Operating Partnership units	50,151							50,151
Redemption of Aimco Operating Partnership units	(9,639)							(9,639)
Amortization of share-based compensation cost (in shares)				22
Amortization of share-based compensation cost	9,765	8,074			8,074			1,691
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
Other, net (in shares)				142
Other, net	152	152		$ 1	151
Net income	708,864	666,227					666,227	42,637
Distributions to noncontrolling interests	(22,310)							(22,310)
Common Stock dividends	(238,067)	(238,067)					(238,067)
Preferred Stock dividends	(8,594)	(8,594)					(8,594)
Balances (in shares) at Dec. 31, 2018			5,000	149,134
Balances at Dec. 31, 2018	$ 1,763,641	$ 1,699,419	$ 125,000	$ 1,491	$ 3,515,641	$ 4,794	$ (1,947,507)	$ 64,222

Consolidated Statements of Part

Consolidated Statements of Partners' Capital - USD ($) $ in Thousands	Total	AIMCO Properties, L.P.	AIMCO Properties, L.P.Preferred Units	AIMCO Properties, L.P.General Partner and Special Limited Partner	AIMCO Properties, L.P.Limited Partners	AIMCO Properties, L.P.Partners’ Capital Attributable to the Partnership	AIMCO Properties, L.P.Noncontrolling Interests
Balances at Dec. 31, 2015		$ 1,763,905	$ 159,126	$ 1,463,265	$ (9,851)	$ 1,612,540	$ 151,365
Increase (Decrease) in Partners' Capital [Roll Forward]
Redemption of preferred units held by Aimco		(34,799)	(34,126)	(673)		(34,799)
Redemption of partnership units held by non-Aimco partners		(10,819)			(10,819)	(10,819)
Amortization of Aimco stock-based compensation		8,610		8,610		8,610
Effect of changes in ownership for consolidated entities		(16,064)		(26,171)	10,107	(16,064)
Change in accumulated other comprehensive income	$ 7,662	7,662		7,051	351	7,402	260
Other, net		3,323		3,323		3,323
Net income		476,034		430,410	20,368	450,778	25,256
Distributions to noncontrolling interests	(35,974)	(25,760)					(25,760)
Distributions to common unitholders		(217,112)		(206,898)	(10,214)	(217,112)
Distributions to preferred unitholders		(10,014)		(10,014)		(10,014)
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 stock-based compensation		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
Other, net		271		271		271
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)
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]
Repurchases of common partnership units		(373,593)		(373,593)		(373,593)
Issuance of common 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 stock-based compensation		9,765		8,074	1,691	9,765
Effect of changes in ownership for consolidated entities		(10,101)		(19,115)	9,014	(10,101)	0
Change in accumulated other comprehensive income	1,260	1,260		1,191	69	1,260
Other, net		152		152		152
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)
Balances at Dec. 31, 2018		$ 1,763,641	$ 125,000	$ 1,574,419	$ 67,189	$ 1,766,608	$ (2,967)

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 716,603	$ 347,079	$ 483,273
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	377,786	366,184	333,066
Provision for real estate impairment loss	0	35,881	0
Gain on dispositions of real estate and the Asset Management business	(677,463)	(300,849)	(400,156)
Income tax benefit	(13,027)	(30,836)	(18,842)
Share-based compensation expense	8,550	7,877	7,629
Amortization of deferred loan costs and other	9,023	5,666	5,060
Other, net	1,065	(7,694)	(6,071)
Changes in operating assets and operating liabilities:
Accounts receivable and other assets	(27,830)	(15,841)	(22,294)
Accounts payable, accrued liabilities and other	1,681	(15,395)	(5,164)
Total adjustments	(320,215)	44,993	(106,772)
Net cash provided by operating activities	396,388	392,072	376,501
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate and deposits related to purchases of real estate	(242,297)	(20,372)	(290,729)
Capital expenditures	(340,489)	(358,104)	(346,645)
Proceeds from dispositions of real estate	708,848	401,983	535,513
Purchases of corporate assets	(7,718)	(8,899)	(7,540)
Proceeds from repayments on notes receivable	5,010	430	412
Other investing activities	(1,508)	(2,019)	9,842
Net cash provided by (used in) investing activities	121,846	13,019	(99,147)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from non-recourse property debt	1,228,027	312,434	417,714
Principal repayments on non-recourse property debt	(976,087)	(409,167)	(371,947)
(Repayment of) proceeds from term loan	(250,000)	250,000	0
Net borrowings on (repayments of) revolving credit facility	93,200	49,230	(9,070)
Payment of debt issue costs	(11,961)	(4,751)	(7,816)
Payment of debt extinguishment costs	(14,241)	(399)	(391)
Repurchases of Common Stock	(373,593)	0	0
Redemptions of Preferred Stock	0	0	(34,799)
Payment of dividends to holders of Preferred Stock	(8,594)	(8,594)	(10,014)
Payment of dividends to holders of Common Stock	(237,504)	(225,377)	(206,279)
Payment of distributions to noncontrolling interests	(29,196)	(26,799)	(35,706)
Other financing activities	5,233	(2,462)	844
Net cash used in financing activities	(588,180)	(393,700)	(283,949)
NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(69,946)	11,391	(6,595)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF PERIOD	142,541	131,150	137,745
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	72,595	142,541	131,150
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	199,996	196,438	200,278
Cash paid for income taxes	11,522	7,401	2,152
Non-cash transactions associated with the acquisition or disposition of real estate:
Non-recourse property debt assumed by buyer in connection with the disposition of the Asset Management business	227,708	0	0
Non-recourse property debt assumed in connection with the acquisition of real estate	208,885	0	0
Issuance of preferred OP Units in connection with acquisition of real estate	0	0	17,000
Issuance of common OP Units in connection with acquisition of real estate	50,151	0	0
Other non-cash transactions:
Accrued capital expenditures (at end of period)	40,185	31,719	35,594
Accrued dividends on TSR restricted stock and LTIP awards (at end of period) (Note 8)	1,266	1,720	927
AIMCO Properties, L.P.
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	716,603	347,079	483,273
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	377,786	366,184	333,066
Provision for real estate impairment loss	0	35,881	0
Gain on dispositions of real estate and the Asset Management business	(677,463)	(300,849)	(400,156)
Income tax benefit	(13,027)	(30,836)	(18,842)
Share-based compensation expense	8,550	7,877	7,629
Amortization of deferred loan costs and other	9,023	5,666	5,060
Other, net	1,065	(7,694)	(6,071)
Changes in operating assets and operating liabilities:
Accounts receivable and other assets	(27,830)	(15,841)	(22,294)
Accounts payable, accrued liabilities and other	1,681	(15,395)	(5,164)
Total adjustments	(320,215)	44,993	(106,772)
Net cash provided by operating activities	396,388	392,072	376,501
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of real estate and deposits related to purchases of real estate	(242,297)	(20,372)	(290,729)
Capital expenditures	(340,489)	(358,104)	(346,645)
Proceeds from dispositions of real estate	708,848	401,983	535,513
Purchases of corporate assets	(7,718)	(8,899)	(7,540)
Proceeds from repayments on notes receivable	5,010	430	412
Other investing activities	(1,508)	(2,019)	9,842
Net cash provided by (used in) investing activities	121,846	13,019	(99,147)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from non-recourse property debt	1,228,027	312,434	417,714
Principal repayments on non-recourse property debt	(976,087)	(409,167)	(371,947)
(Repayment of) proceeds from term loan	(250,000)	250,000	0
Net borrowings on (repayments of) revolving credit facility	93,200	49,230	(9,070)
Payment of debt issue costs	(11,961)	(4,751)	(7,816)
Payment of debt extinguishment costs	(14,241)	(399)	(391)
Repurchases of Common Stock	(373,593)	0	0
Redemptions of Preferred Stock	0	0	(34,799)
Payment of dividends to holders of Preferred Stock	(16,334)	(16,358)	(17,253)
Payment of distributions to General Partner and Special Limited Partner	(237,504)	(225,377)	(206,279)
Payment of distributions to Limited Partners	(11,987)	(10,668)	(10,214)
Payment of distributions to noncontrolling interests	(9,469)	(8,367)	(18,253)
Redemptions of noncontrolling interests in the Aimco Operating Partnership	(9,885)	(13,546)	(12,544)
Redemption of common and preferred units	(9,885)	(13,546)	(12,544)
Redemptions of noncontrolling interests in the Aimco Operating Partnership	(3,579)	(314,269)	(13,941)
Other financing activities	5,233	(2,462)	844
Net cash used in financing activities	(588,180)	(393,700)	(283,949)
NET (DECREASE) INCREASE IN CASH, CASH EQUIVALENTS AND RESTRICTED CASH	(69,946)	11,391	(6,595)
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF PERIOD	142,541	131,150	137,745
CASH, CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	72,595	142,541	131,150
SUPPLEMENTAL CASH FLOW INFORMATION:
Interest paid	199,996	196,438	200,278
Cash paid for income taxes	11,522	7,401	2,152
Non-cash transactions associated with the acquisition or disposition of real estate:
Non-recourse property debt assumed by buyer in connection with the disposition of the Asset Management business	227,708	0	0
Issuance of preferred OP Units in connection with acquisition of real estate	0	0	17,000
Other non-cash transactions:
Accrued capital expenditures (at end of period)	40,185	31,719	35,594
Accrued dividends on TSR restricted stock and LTIP awards (at end of period) (Note 8)	2,217	1,818	927
AIMCO PROPERTIES, L.P.
CASH FLOWS FROM FINANCING ACTIVITIES:
Redemptions of noncontrolling interests in the Aimco Operating Partnership	(3,579)	(314,269)	(13,941)
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	$ 208,885	$ 0	$ 0

Organization

Organization	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	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 limited 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, owns 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 partnership preferred units, which we refer to as preferred OP Units. As of December 31, 2018 , after eliminations for units held by consolidated subsidiaries, the Aimco Operating Partnership had 158,140,169 common partnership units outstanding. As of December 31, 2018 , Aimco owned 149,133,826 of the common partnership units ( 94.3% of the common partnership units) of the Aimco Operating Partnership and Aimco had outstanding an equal number of shares of its Class A Common Stock, 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. As of December 31, 2018 , we owned an equity interest in 134 apartment communities with 36,549 apartment homes in our Real Estate portfolio. Our Real Estate portfolio, is diversified by both price point and geography and consists of market rate apartment communities in which we own a substantial interest. We consolidated 130 of these apartment communities with 36,407 apartment homes and these communities comprise our reportable segment. 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 (see Note 13 ). All significant intercompany balances have been eliminated in consolidation. Interests in the Aimco Operating Partnership that are held by limited partners other than Aimco are reflected in Aimco’s accompanying consolidated balance sheets as noncontrolling interests in Aimco Operating Partnership. Interests in partnerships consolidated by the Aimco Operating Partnership that are held by third parties are reflected in our accompanying consolidated balance sheets as noncontrolling interests in consolidated real estate partnerships. 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. 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. Acquisition of Real Estate and Related Depreciation and Amortization We generally recognize the acquisition of apartment communities or interests in partnerships that own apartment communities at our cost. The related transaction costs are included in the cost of the acquired apartment community. We allocate the cost of apartment communities acquired based on the relative fair value of the assets acquired and liabilities assumed. 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. 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 apartment community. At December 31, 2018 , the weighted average depreciable life of our buildings and improvements was approximately 28 years. Furniture, fixtures and equipment associated with apartment communities are depreciated over five years. 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. At December 31, 2018 and 2017 , deferred income in our consolidated balance sheets included below-market lease amounts totaling $18.7 million and $9.1 million , respectively, which are net of accumulated amortization of $36.7 million and $34.4 million , respectively. During the years ended December 31, 2018 , 2017 and 2016 , we included amortization of below-market leases of $2.3 million , $1.3 million and $1.7 million , respectively, in rental and other property revenues in our consolidated statements of operations. At December 31, 2018 , our below-market leases had a weighted average amortization period of 6.3 years and estimated aggregate amortization for each of the five succeeding years as follows (in thousands): Estimated Amortization 2019 $1,986 2020 1,741 2021 1,668 2022 1,621 2023 1,571 Capital Additions and Related Depreciation 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 site 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 redevelopments, developments and 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 apartment 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. 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. All capitalized site 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. Certain homogeneous items that are purchased in bulk on a recurring basis, such as carpeting and 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. For the years ended December 31, 2018 , 2017 and 2016 , we capitalized to buildings and improvements $7.6 million , $7.6 million and $9.6 million of interest costs, respectively, and $36.8 million , $36.0 million and $32.9 million of other direct and indirect costs, respectively. Impairment of Long-Lived Assets 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 make an assessment of its recoverability by comparing the carrying amount to our estimate of the undiscounted future cash flows, excluding interest charges, of the apartment 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 apartment community. 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, tax and insurance escrow accounts held by lenders and resident security deposits. Other Assets At December 31, 2018 and 2017 , other assets was comprised of the following amounts (dollars in thousands): 2018 2017 Investments in securitization trust that holds Aimco property debt $ 83,587 $ 82,794 Deferred tax asset, net (Note 9) 67,060 32,227 Intangible assets, net 43,424 38,701 Prepaid expenses, real estate taxes and insurance 25,657 25,144 Software, equipment and leasehold improvements 18,309 20,048 Investments in unconsolidated real estate partnerships 12,650 12,636 Accounts and notes receivable, net 55,630 17,035 Deferred costs, deposits and other 45,224 44,154 Total other assets $ 351,541 $ 272,739 The table above excludes other assets of partnerships served by our Asset Management business at December 31, 2017 , as they are presented separately on our consolidated balance sheet. 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. Refer to Note 11 for further information regarding these debt securities. Intangible Assets At December 31, 2018 and 2017 , other assets included goodwill associated with our reportable segment of $37.8 million . We perform an annual impairment test of goodwill by evaluating qualitative factors to determine the likelihood that goodwill may be impaired. We primarily consider the fair value of our real estate portfolio and the fair value of our debt relative to their carrying values. As a result of the qualitative analysis, we do not believe our goodwill is impaired as of the date of our annual test. Capitalized Software Costs, Equipment and Leasehold Improvements 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. 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 recognized by and related to such entities, and we present such amounts within other, net in our consolidated statements of operations. The excess of the cost of the acquired partnership interests over the historical carrying amount of partners’ equity or deficit is generally ascribed to the fair values of land and buildings owned by the partnerships. We amortize the excess cost related 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. Deferred Costs We defer, as debt issue 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 issue costs over the term of the modified loan agreement. Debt issue costs associated with our revolving credit facility are included in other assets on our consolidated balance sheets. Debt issue costs associated with non-recourse property debt and our term loan are presented as a direct deduction from the related liabilities on our consolidated balance sheets. When financing arrangements are repaid or otherwise extinguished prior to maturity, unamortized debt issue costs are written off, additionally, any lender fees or other costs incurred in connection with the extinguishment are recognized. Amortization and write-off of debt issue costs and other extinguishment costs are included in interest expense on our consolidated statements of operations. We defer leasing commissions and other direct costs incurred in connection with successful leasing efforts and amortize the costs over the terms of the related leases. Beginning in 2019, in connection with our adoption of the new accounting standard for leases, which is further discussed under the Recent Accounting Pronouncements heading below, such costs will be deferred when they are incremental and would not have incurred if the contract had not been obtained. Amortization of these costs is included in depreciation and amortization. Noncontrolling Interests in Consolidated Real Estate Partnerships We 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. 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, 2018 , 2017 and 2016 , 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 on disposition 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. Noncontrolling Interests in Aimco Operating Partnership Noncontrolling interests in Aimco Operating Partnership consist of common OP Units and preferred OP Units. 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 partnership units based on the weighted average number of common partnership units (including those held by Aimco) outstanding during the period. During the years ended December 31, 2018 , 2017 and 2016 , the holders of common OP Units had a weighted average ownership interest in the Aimco Operating Partnership of 4.9% , 4.5% and 4.7% , respectively. See Note 7 for further information regarding the items comprising noncontrolling interests in the Aimco Operating Partnership. Revenue from Leases Our apartment communities have operating leases with apartment residents with terms averaging 13 months. We recognize rental revenue related to these leases, net of any concessions, on a straight-line basis over the term of the lease. Our operating leases with residents 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 are variable payments pursuant to the related lease and recognized as income when the utility expense is incurred. 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 on our consolidated statements of operations. 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 recognized income from asset management and other services when the related fees were earned and realized or realizable. The tax credits were generally realized ratably over the first ten years of the tax credit arrangement and are subject to the partnership’s compliance with applicable laws and regulations for a period of 15 years . We held nominal ownership positions in these partnerships, generally less than one percent, and sold these interests to an unrelated third party in July 2018. In our role, we provided asset management and other services to these partnerships and we received fees and other payments in return. Capital contributions received by the partnerships from tax credit investors represented, in substance, consideration that we received in exchange for our obligation to deliver tax credits and other tax benefits to the investors. We recorded these contributions as deferred income in our consolidated balance sheets upon receipt, and we recognized these amounts as revenue in our consolidated statements of operations when our obligation to the investors is relieved upon delivery of the tax benefits. This obligation transferred to the buyer along with our interest in the partnerships. Prior to the sale of our interests in the partnerships, we consolidated the low-income housing tax credit partnerships in which we were the sole general partner, because we were the sole decision maker of the partnerships. When the contractual arrangements obligated us to deliver tax benefits to the investors, and entitled us through fee arrangements to receive substantially all available cash flow from the partnerships, we recognized the income or loss generated by the underlying real estate based on our economic interest in the partnerships’ current period results, which was approximately 100% and represented the allocation of cash available for distribution we would receive from a hypothetical liquidation at the book value of the partnership’s net assets. Our economic interests generally differed from our legal interests. Upon the sale of our interests in these partnerships, we deconsolidated these partnerships and removed the obligation to deliver future tax credits and benefits, represented by the remaining deferred income as a component of our gain on the sale of the business. 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. See Note 8 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 our 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. Refer to Note 9 for further information about our income taxes. Comprehensive Income or Loss As discussed under the preceding Investments in Securitization Trust that holds Aimco Property Debt heading, we have investments in debt securities that are measured at fair value with unrealized gains or losses recognized as an adjustment of accumulated other comprehensive loss within equity and partners’ capital. Additionally, during the year ended December 31, 2018 , we recognized changes in the fair value of our cash flow hedges as an adjustment of accumulated other comprehensive loss within equity and partners’ capital until the July 2018 sale of the Asset Management business. The amounts of consolidated comprehensive income for the years ended December 31, 2018 , 2017 and 2016 , along with the corresponding amounts of such comprehensive income attributable to Aimco, the Aimco Operating Partnership and to noncontrolling interests, are presented within the accompanying consolidated statements of comprehensive income. 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. See Note 10 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 Certain items included in the 2017 and 2016 consolidated financial statements have been reclassified to conform to the current presentation. We have also reclassified certain items on our consolidated statements of operations to comply with the SEC disclosure amendments summarized below. Accounting Pronouncements Adopted in the Current Year Effective January 1, 2018, we adopted a new standard issued by the Financial Accounting Standards Board, or FASB, that affects accounting for revenue. Under this new standard, revenue is generally recognized when an entity has transferred control of goods or services to a customer for an amount reflecting the consideration to which the entity expects to be entitled for such exchange. The new revenue standard also introduced new guidance for accounting for other income, including how we measure gains or losses on the sale of real estate. We adopted the new standard using the modified retrospective transition method effective January 1, 2018, with no effect on our results of operations or financial position. Effective January 1, 2018, we also adopted new standards issued by the FASB that affect the presentation and disclosure of the statements of cash flows. We are now required to present combined inflows and outflows of cash, cash equivalents, and restricted cash in the consolidated statement of cash flows. Previously our consolidated statements of cash flows presented transfers between restricted and unrestricted cash accounts as operating, financing and investing cash activities depending on the required or intended purpose for the restricted funds. The new guidance also requires debt prepayment and other extinguishment-related payments to be classified as financing activities. We previously classified such payments as operating activities. We have revised our consolidated statements of cash flows for the years ended December 31, 2017 and 2016 to conform to this presentation, and the effect of the revisions to net cash flows from operating, investing, and financing activities as previously reported are summarized in the following table (in thousands): 2017 2016 As Previously Reported Adjustments As Revised As Previously Reported Adjustments As Revised Net cash provided by operating activities $ 394,139 $ (2,067 ) $ 392,072 $ 377,724 $ (1,223 ) $ 376,501 Net cash used in investing activities 14,704 (1,685 ) 13,019 (97,773 ) (1,374 ) (99,147 ) Net cash used in financing activities (393,301 ) (399 ) (393,700 ) (269,496 ) (14,453 ) (283,949 ) 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 and were generally effective on November 5, 2018. The amendments remove the SEC rule that requires REITs to present gain or loss on the sale of re

Basis of Presentation and Summa

Basis of Presentation and Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Summary of Significant Accounting Policies	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 limited 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, owns 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 partnership preferred units, which we refer to as preferred OP Units. As of December 31, 2018 , after eliminations for units held by consolidated subsidiaries, the Aimco Operating Partnership had 158,140,169 common partnership units outstanding. As of December 31, 2018 , Aimco owned 149,133,826 of the common partnership units ( 94.3% of the common partnership units) of the Aimco Operating Partnership and Aimco had outstanding an equal number of shares of its Class A Common Stock, 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. As of December 31, 2018 , we owned an equity interest in 134 apartment communities with 36,549 apartment homes in our Real Estate portfolio. Our Real Estate portfolio, is diversified by both price point and geography and consists of market rate apartment communities in which we own a substantial interest. We consolidated 130 of these apartment communities with 36,407 apartment homes and these communities comprise our reportable segment. 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 (see Note 13 ). All significant intercompany balances have been eliminated in consolidation. Interests in the Aimco Operating Partnership that are held by limited partners other than Aimco are reflected in Aimco’s accompanying consolidated balance sheets as noncontrolling interests in Aimco Operating Partnership. Interests in partnerships consolidated by the Aimco Operating Partnership that are held by third parties are reflected in our accompanying consolidated balance sheets as noncontrolling interests in consolidated real estate partnerships. 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. 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. Acquisition of Real Estate and Related Depreciation and Amortization We generally recognize the acquisition of apartment communities or interests in partnerships that own apartment communities at our cost. The related transaction costs are included in the cost of the acquired apartment community. We allocate the cost of apartment communities acquired based on the relative fair value of the assets acquired and liabilities assumed. 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. 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 apartment community. At December 31, 2018 , the weighted average depreciable life of our buildings and improvements was approximately 28 years. Furniture, fixtures and equipment associated with apartment communities are depreciated over five years. 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. At December 31, 2018 and 2017 , deferred income in our consolidated balance sheets included below-market lease amounts totaling $18.7 million and $9.1 million , respectively, which are net of accumulated amortization of $36.7 million and $34.4 million , respectively. During the years ended December 31, 2018 , 2017 and 2016 , we included amortization of below-market leases of $2.3 million , $1.3 million and $1.7 million , respectively, in rental and other property revenues in our consolidated statements of operations. At December 31, 2018 , our below-market leases had a weighted average amortization period of 6.3 years and estimated aggregate amortization for each of the five succeeding years as follows (in thousands): Estimated Amortization 2019 $1,986 2020 1,741 2021 1,668 2022 1,621 2023 1,571 Capital Additions and Related Depreciation 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 site 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 redevelopments, developments and 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 apartment 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. 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. All capitalized site 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. Certain homogeneous items that are purchased in bulk on a recurring basis, such as carpeting and 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. For the years ended December 31, 2018 , 2017 and 2016 , we capitalized to buildings and improvements $7.6 million , $7.6 million and $9.6 million of interest costs, respectively, and $36.8 million , $36.0 million and $32.9 million of other direct and indirect costs, respectively. Impairment of Long-Lived Assets 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 make an assessment of its recoverability by comparing the carrying amount to our estimate of the undiscounted future cash flows, excluding interest charges, of the apartment 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 apartment community. 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, tax and insurance escrow accounts held by lenders and resident security deposits. Other Assets At December 31, 2018 and 2017 , other assets was comprised of the following amounts (dollars in thousands): 2018 2017 Investments in securitization trust that holds Aimco property debt $ 83,587 $ 82,794 Deferred tax asset, net (Note 9) 67,060 32,227 Intangible assets, net 43,424 38,701 Prepaid expenses, real estate taxes and insurance 25,657 25,144 Software, equipment and leasehold improvements 18,309 20,048 Investments in unconsolidated real estate partnerships 12,650 12,636 Accounts and notes receivable, net 55,630 17,035 Deferred costs, deposits and other 45,224 44,154 Total other assets $ 351,541 $ 272,739 The table above excludes other assets of partnerships served by our Asset Management business at December 31, 2017 , as they are presented separately on our consolidated balance sheet. 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. Refer to Note 11 for further information regarding these debt securities. Intangible Assets At December 31, 2018 and 2017 , other assets included goodwill associated with our reportable segment of $37.8 million . We perform an annual impairment test of goodwill by evaluating qualitative factors to determine the likelihood that goodwill may be impaired. We primarily consider the fair value of our real estate portfolio and the fair value of our debt relative to their carrying values. As a result of the qualitative analysis, we do not believe our goodwill is impaired as of the date of our annual test. Capitalized Software Costs, Equipment and Leasehold Improvements 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. 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 recognized by and related to such entities, and we present such amounts within other, net in our consolidated statements of operations. The excess of the cost of the acquired partnership interests over the historical carrying amount of partners’ equity or deficit is generally ascribed to the fair values of land and buildings owned by the partnerships. We amortize the excess cost related 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. Deferred Costs We defer, as debt issue 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 issue costs over the term of the modified loan agreement. Debt issue costs associated with our revolving credit facility are included in other assets on our consolidated balance sheets. Debt issue costs associated with non-recourse property debt and our term loan are presented as a direct deduction from the related liabilities on our consolidated balance sheets. When financing arrangements are repaid or otherwise extinguished prior to maturity, unamortized debt issue costs are written off, additionally, any lender fees or other costs incurred in connection with the extinguishment are recognized. Amortization and write-off of debt issue costs and other extinguishment costs are included in interest expense on our consolidated statements of operations. We defer leasing commissions and other direct costs incurred in connection with successful leasing efforts and amortize the costs over the terms of the related leases. Beginning in 2019, in connection with our adoption of the new accounting standard for leases, which is further discussed under the Recent Accounting Pronouncements heading below, such costs will be deferred when they are incremental and would not have incurred if the contract had not been obtained. Amortization of these costs is included in depreciation and amortization. Noncontrolling Interests in Consolidated Real Estate Partnerships We 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. 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, 2018 , 2017 and 2016 , 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 on disposition 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. Noncontrolling Interests in Aimco Operating Partnership Noncontrolling interests in Aimco Operating Partnership consist of common OP Units and preferred OP Units. 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 partnership units based on the weighted average number of common partnership units (including those held by Aimco) outstanding during the period. During the years ended December 31, 2018 , 2017 and 2016 , the holders of common OP Units had a weighted average ownership interest in the Aimco Operating Partnership of 4.9% , 4.5% and 4.7% , respectively. See Note 7 for further information regarding the items comprising noncontrolling interests in the Aimco Operating Partnership. Revenue from Leases Our apartment communities have operating leases with apartment residents with terms averaging 13 months. We recognize rental revenue related to these leases, net of any concessions, on a straight-line basis over the term of the lease. Our operating leases with residents 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 are variable payments pursuant to the related lease and recognized as income when the utility expense is incurred. 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 on our consolidated statements of operations. 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 recognized income from asset management and other services when the related fees were earned and realized or realizable. The tax credits were generally realized ratably over the first ten years of the tax credit arrangement and are subject to the partnership’s compliance with applicable laws and regulations for a period of 15 years . We held nominal ownership positions in these partnerships, generally less than one percent, and sold these interests to an unrelated third party in July 2018. In our role, we provided asset management and other services to these partnerships and we received fees and other payments in return. Capital contributions received by the partnerships from tax credit investors represented, in substance, consideration that we received in exchange for our obligation to deliver tax credits and other tax benefits to the investors. We recorded these contributions as deferred income in our consolidated balance sheets upon receipt, and we recognized these amounts as revenue in our consolidated statements of operations when our obligation to the investors is relieved upon delivery of the tax benefits. This obligation transferred to the buyer along with our interest in the partnerships. Prior to the sale of our interests in the partnerships, we consolidated the low-income housing tax credit partnerships in which we were the sole general partner, because we were the sole decision maker of the partnerships. When the contractual arrangements obligated us to deliver tax benefits to the investors, and entitled us through fee arrangements to receive substantially all available cash flow from the partnerships, we recognized the income or loss generated by the underlying real estate based on our economic interest in the partnerships’ current period results, which was approximately 100% and represented the allocation of cash available for distribution we would receive from a hypothetical liquidation at the book value of the partnership’s net assets. Our economic interests generally differed from our legal interests. Upon the sale of our interests in these partnerships, we deconsolidated these partnerships and removed the obligation to deliver future tax credits and benefits, represented by the remaining deferred income as a component of our gain on the sale of the business. 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. See Note 8 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 our 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. Refer to Note 9 for further information about our income taxes. Comprehensive Income or Loss As discussed under the preceding Investments in Securitization Trust that holds Aimco Property Debt heading, we have investments in debt securities that are measured at fair value with unrealized gains or losses recognized as an adjustment of accumulated other comprehensive loss within equity and partners’ capital. Additionally, during the year ended December 31, 2018 , we recognized changes in the fair value of our cash flow hedges as an adjustment of accumulated other comprehensive loss within equity and partners’ capital until the July 2018 sale of the Asset Management business. The amounts of consolidated comprehensive income for the years ended December 31, 2018 , 2017 and 2016 , along with the corresponding amounts of such comprehensive income attributable to Aimco, the Aimco Operating Partnership and to noncontrolling interests, are presented within the accompanying consolidated statements of comprehensive income. 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. See Note 10 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 Certain items included in the 2017 and 2016 consolidated financial statements have been reclassified to conform to the current presentation. We have also reclassified certain items on our consolidated statements of operations to comply with the SEC disclosure amendments summarized below. Accounting Pronouncements Adopted in the Current Year Effective January 1, 2018, we adopted a new standard issued by the Financial Accounting Standards Board, or FASB, that affects accounting for revenue. Under this new standard, revenue is generally recognized when an entity has transferred control of goods or services to a customer for an amount reflecting the consideration to which the entity expects to be entitled for such exchange. The new revenue standard also introduced new guidance for accounting for other income, including how we measure gains or losses on the sale of real estate. We adopted the new standard using the modified retrospective transition method effective January 1, 2018, with no effect on our results of operations or financial position. Effective January 1, 2018, we also adopted new standards issued by the FASB that affect the presentation and disclosure of the statements of cash flows. We are now required to present combined inflows and outflows of cash, cash equivalents, and restricted cash in the consolidated statement of cash flows. Previously our consolidated statements of cash flows presented transfers between restricted and unrestricted cash accounts as operating, financing and investing cash activities depending on the required or intended purpose for the restricted funds. The new guidance also requires debt prepayment and other extinguishment-related payments to be classified as financing activities. We previously classified such payments as operating activities. We have revised our consolidated statements of cash flows for the years ended December 31, 2017 and 2016 to conform to this presentation, and the effect of the revisions to net cash flows from operating, investing, and financing activities as previously reported are summarized in the following table (in thousands): 2017 2016 As Previously Reported Adjustments As Revised As Previously Reported Adjustments As Revised Net cash provided by operating activities $ 394,139 $ (2,067 ) $ 392,072 $ 377,724 $ (1,223 ) $ 376,501 Net cash used in investing activities 14,704 (1,685 ) 13,019 (97,773 ) (1,374 ) (99,147 ) Net cash used in financing activities (393,301 ) (399 ) (393,700 ) (269,496 ) (14,453 ) (283,949 ) 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 and were generally effective on November 5, 2018. The amendments remove the SEC rule that requires REITs to present gain or loss on the sale of re

Significant Transactions

Significant Transactions	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Significant Transactions	Significant Transactions Acquisitions of Apartment Communities During the year ended December 31, 2018 , we acquired apartment communities located in Arlington, Virginia, Fairfax County, Virginia and in the Center City and University City areas of Philadelphia. Summarized information regarding these acquisitions is set forth in the table below (dollars in thousands): 2018 Number of apartment communities 6 Number of apartment homes 1,480 Purchase price (1) $ 483,066 Capitalized transaction costs 7,591 Total fair value allocated to land 69,177 Total fair value allocated to building and improvements 424,718 Total fair value allocated to intangible assets 9,700 Total fair value allocated to intangible liabilities 12,938 (1) The gross purchase price of the Philadelphia portfolio consisted of $34.4 million in cash, $208.9 million of assumed property-level debt and the issuance of 1.2 million OP Units. In accordance with GAAP, the OP Units were valued at $41.08 per unit, the closing price of Aimco’s common share on May 1, 2018, the purchase date. Dispositions of Apartment Communities and Assets Held for Sale During the year ended December 31, 2018 , we 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 encumbering the Hunters Point apartment communities. In addition to the Hunters Point apartment communities, we sold the following apartment communities from our Real Estate portfolio during the years ended December 31, 2018 , 2017 and 2016 (dollars in thousands): 2018 2017 2016 Real Estate portfolio: Apartment communities sold 4 5 7 Apartment homes sold 1,334 2,291 3,045 Gain on dispositions of real estate $ 175,213 $ 297,730 $ 383,647 The apartment communities sold from our Real Estate portfolio during 2018 , 2017 and 2016 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 sold our interests in the entities owning the La Jolla Cove property in settlement of legal actions filed in 2014 by a group of disappointed buyers who had hoped to acquire the property. We provided seller financing with a stated value of $48.6 million and received net cash proceeds of approximately $5.0 million in the sale. During the years ended December 31, 2017 and 2016, the consolidated partnerships served by our Asset Management business sold a total of three apartment communities for gross proceeds of $10.9 million and $27.5 million , respectively, and resulting in gains on dispositions of $2.6 million and $16.5 million , respectively. In addition to the apartment communities we sold during the periods presented, from time to time we may be marketing for sale certain apartment communities that are inconsistent with our long-term investment strategy. At the end of each reporting period, we evaluate whether such communities meet the criteria to be classified as held for sale. As of December 31, 2018 , we had two apartment communities with 782 apartment homes in our Real Estate portfolio that were classified as held for sale. In January 2019, we sold the apartment communities for a gain on disposition of $87.5 million , net of tax, and gross proceeds of $141.2 million , resulting in $114.9 million of net proceeds to Aimco.

Non-Recourse Property Debt and

Non-Recourse Property Debt and Credit Agreement	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Non-Recourse Property Debt and Credit Agreement	Non-Recourse Property Debt and Credit Agreement Non-Recourse Property Debt (Real Estate Portfolio) We finance apartment communities in our Real Estate 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 at December 31, 2018 and 2017 (in thousands): 2018 2017 Fixed-rate property debt $ 3,676,882 $ 3,480,378 Variable-rate property debt 260,118 82,663 Debt issue costs, net of accumulated amortization (21,695 ) (17,932 ) Non-recourse property debt, net $ 3,915,305 $ 3,545,109 Fixed-rate property debt matures at various dates through January 2055 , and has interest rates that range from 2.73% to 7.14% , with a weighted average interest rate of 4.22% . Principal and interest on fixed-rate debt are generally payable monthly or in monthly interest-only payments with balloon payments due at maturity. At December 31, 2018 , each of the fixed-rate loans payable related to apartment communities classified as held for use were secured by one of 82 apartment communities that had an aggregate net book value of $4.2 billion . Variable-rate property debt matures at various dates through July 2033 , and had interest rates that ranged from 3.55% to 3.67% , as of December 31, 2018 , with a weighted average interest rate of 3.61% at December 31, 2018 . Principal and interest on variable-rate debt are generally payable in semi-annual installments with balloon payments due at maturity. As of December 31, 2018 , our variable-rate property debt related to apartment communities classified as held for use were each secured by eight apartment communities that had an aggregate net book value of $239.5 million . These non-recourse property debt instruments contain covenants common to the type of borrowing, and at December 31, 2018 , we were in compliance with all such covenants. As of December 31, 2018 , the scheduled principal amortization and maturity payments for the non-recourse property debt related to apartment communities classified as held for use were as follows (in thousands): Amortization Maturities 2019 $ 77,791 $ 168,554 2020 79,592 78,930 2021 (1) 69,995 611,039 2022 64,991 283,629 2023 55,450 337,871 Thereafter 2,109,158 Total $ 3,937,000 (1) Pursuant to the terms of our loan agreements, we may prepay in 2020 $246.5 million of loans maturing in 2021, without penalty. Credit Facility We have a credit facility with a syndicate of financial institutions. Our credit facility provides for $800.0 million of revolving loan commitments. As of December 31, 2018 and 2017 , we had $160.4 million and $67.2 million , respectively, of outstanding borrowings under our revolving credit facility. The interest rate on our outstanding borrowings was 3.93% and 3.26% at December 31, 2018 and 2017 , respectively. As of December 31, 2018 , after outstanding borrowings and $7.1 million of undrawn letters of credit backed by the Credit Agreement, our available borrowing capacity was $632.5 million . During the year ended December 31, 2018 , we repaid the $250.0 million term loan in full. 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% at December 31, 2018 ). The credit facility matures on January 22, 2022 . The 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 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, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Commitments In connection with our redevelopment, development and capital improvement activities, we have entered into various construction-related contracts and we have made commitments to complete redevelopment of certain apartment communities, pursuant to financing or other arrangements. As of December 31, 2018 , our commitments related to these capital activities totaled approximately $207.0 million , most of which we expect to incur during the next 12 months. We enter into certain commitments for future purchases of goods and services in connection with the operations of our apartment communities. Those commitments generally have terms of one year or less and reflect expenditure levels comparable to our historical expenditures. Legal Matters In addition to the matters described below, we are a party to various legal actions and administrative proceedings arising in the ordinary course of business, some of which are covered by our general liability insurance program, and none of which we expect to have a material adverse effect on our consolidated financial condition, results of operations or cash flows. Environmental Various federal, state and local laws subject apartment community owners or operators to liability for management, and the costs of removal or remediation, of certain potentially hazardous materials that may be present in the land or buildings of an apartment community. Such laws often impose liability without regard to fault or whether the owner or operator knew of, or was responsible for, the presence of such materials. The presence of, or the failure to manage or remediate properly, these materials may adversely affect occupancy at such apartment communities as well as the ability to sell or finance such apartment communities. In addition, governmental agencies may bring claims for costs associated with investigation and remediation actions. Moreover, private plaintiffs may potentially make claims for investigation and remediation costs they incur or for personal injury, disease, disability or other infirmities related to the alleged presence of hazardous materials. In addition to potential environmental liabilities or costs associated with our current apartment communities, we may also be responsible for such liabilities or costs associated with communities we acquire or manage in the future, or apartment communities we no longer own or operate. We are engaged in discussions with the Environmental Protection Agency, or EPA, and the Indiana Department of Environmental Management, or IDEM, regarding contaminated groundwater in a residential area 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 IDEM’s oversight. In 2016, EPA listed our former community and a number of residential communities in the vicinity on the National Priorities List, or NPL (i.e. as a Superfund site). In May 2018, we prevailed on our federal judicial appeal vacating the Superfund listing. We continue to work with EPA and IDEM to identify options for clean-up of the site. Although the outcome of these processes are uncertain, we do not expect their resolution to have a material adverse effect on our consolidated financial condition, results of operations or cash flows. We also have been contacted by regulators and the current owner of a property in Lake Tahoe, California, regarding environmental issues allegedly stemming from the historic operation of a dry cleaner. An entity owned by us was the former general partner of a now-dissolved partnership that previously owned a site that was used for dry cleaning. That entity and the current property owner have been remediating the dry cleaner site since 2009, under the oversight of the Lahontan Regional Water Quality Control Board, or Lahontan. In May 2017, Lahontan issued a final cleanup and abatement order that names four potentially-responsible parties, acknowledges that there may be additional responsible parties, and requires the named parties to perform additional groundwater investigation and corrective actions with respect to onsite and offsite contamination. We are appealing the final order while simultaneously complying with it. Although the outcome of this process is uncertain, we do not expect its resolution to have a material adverse effect on our consolidated financial condition, results of operations or cash flows. We have determined that our legal obligations to remove or remediate certain potentially hazardous materials may be conditional asset retirement obligations, as defined in GAAP. Except in limited circumstances where the asset retirement activities are expected to be performed in connection with a planned construction project or apartment community casualty, we believe that the fair value of our asset retirement obligations cannot be reasonably estimated due to significant uncertainties in the timing and manner of settlement of those obligations. Asset retirement obligations that are reasonably estimable as of December 31, 2018 , are immaterial to our consolidated financial condition, results of operations and cash flows. Operating Leases We are obligated under non-cancelable operating leases for office space. We are also obligated under non-cancelable operating leases for the ground under certain of our apartment communities with remaining terms ranging from 52 years to 99 years . Minimum annual rental payments under operating leases are as follows (in thousands): Office Lease Obligations Ground Lease Obligations Total Operating Lease Obligations 2019 $ 2,237 $ 2,114 $ 4,351 2020 2,821 2,350 5,171 2021 2,719 2,439 5,158 2022 2,582 2,492 5,074 2023 1,871 2,492 4,363 Thereafter 10,644 422,169 432,813 Total $ 22,874 $ 434,056 $ 456,930 Substantially all of the office space subject to the operating leases in the table above is for the use of our corporate offices and area operations. Rent expense is generally recognized on a straight-line basis and totaled $2.8 million , $3.0 million and $3.3 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Rent expense recognized for the ground leases totaled $2.3 million , $1.8 million and $1.7 million for the years ended December 31, 2018 , 2017 and 2016 , respectively, and is included within interest expense in the accompanying statements of operations.

Aimco Equity

Aimco Equity	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Aimco Equity	Aimco Equity Preferred Stock At December 31, 2018 and 2017 , Aimco had a single class of perpetual preferred stock outstanding, its Class A Cumulative Preferred Stock, with 5,000,000 shares authorized, issued and outstanding and with a balance of $125.0 million as of December 31, 2018 and 2017 . Aimco’s Class A Preferred Stock has a $0.01 per share par value, is senior to Aimco’s Common Stock, has a liquidation preference per share of $25.00 and is redeemable at our option on or after May 17, 2019 . The holders of Preferred Stock are generally not entitled to vote on matters submitted to stockholders. Dividends at an annual rate of 6.88% are subject to declaration by Aimco’s Board of Directors and accrue if not declared. During the year ended December 31, 2016 , Aimco redeemed all of the outstanding shares of its Class Z Cumulative Preferred Stock at a redemption value of $34.8 million . We reflected the $0.7 million excess of the redemption value over the carrying amount and $1.3 million of previously deferred issuance costs as an adjustment of net income attributable to preferred stockholders for the year ended December 31, 2016 . In connection with the redemption of Aimco preferred stock, the Aimco Operating Partnership redeemed from Aimco a number of Partnership Preferred Units equal to the number of shares redeemed or repurchased by Aimco. Common Stock During the years ended December 31, 2018 , 2017 and 2016 , Aimco declared dividends per common share of $1.52 , $1.44 and $1.32 , respectively. On February 3, 2019, Aimco’s Board of Directors authorized a reverse stock split, in which every 1.03119 Aimco common share will be 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 consists of $67.1 million in cash and 4.5 million shares of Aimco common stock. The special dividend will be payable on March 22, 2019, to stockholders of record as of February 22, 2019. The special dividend amount includes the regular quarterly cash dividend, which for 2019 is expected to be $0.39 per share. Stockholders will have the opportunity to elect to receive the special dividend in the form of all cash or all stock, subject to proration if either option is oversubscribed. The reverse split was authorized in order to neutralize the dilutive impact of the stock issued in the special dividend. As a result, total shares outstanding following completion of both the special dividend and the reverse stock split are expected to be unchanged from the total shares outstanding immediately prior to the transactions. Some stockholders may have more Aimco shares and some may have fewer based on their individual elections. Pro forma Earnings per Share (unaudited) In financial statements issued after the effective date of the reverse stock split, we are required to retroactively recognize the reverse stock split in the calculation of basic and diluted earnings per share. The shares issued in connection with the special dividend will be included in the calculation of basic and diluted earnings per share on a prospective basis, and are therefore not included in the pro forma amounts disclosed below. If the reverse stock split had been effective prior to issuance of these financial statements, basic and diluted weighted average shares outstanding and earnings per share for the years ending December 31, 2018, 2017 and 2016 would have been (shares in thousands): 2018 2017 2016 Weighted average shares, basic 151,152 151,595 151,282 Weighted average shares, diluted 151,334 152,060 151,669 Basic earnings per share $ 4.34 $ 2.02 $ 2.76 Diluted earnings per share $ 4.34 $ 2.02 $ 2.75 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, 2018
Partners' Capital [Abstract]
Partners' Capital	Partners’ Capital Partnership Preferred Units Owned by Aimco At December 31, 2018 and 2017 , the Aimco Operating Partnership had outstanding preferred units in classes and amounts similar to Aimco’s Preferred Stock described in Note 6 , or Partnership Preferred Units. All of these Partnership Preferred Units were owned by Aimco during the periods presented. The Partnership Preferred Units are senior to the Aimco Operating Partnership’s common partnership units. The Partnership Preferred Units do not have voting rights, except the right to approve certain changes to the Aimco Operating Partnership’s Partnership Agreement that would adversely affect holders of such class of units. Distributions on Partnership Preferred Units are subject to being declared by the General Partner. The Partnership Preferred Units are redeemable by the Aimco Operating Partnership only in connection with a concurrent redemption by Aimco of the corresponding Aimco Preferred Stock held by unrelated parties. As discussed in Note 6 , during the year ended December 31, 2016 , Aimco redeemed its Class Z Cumulative Preferred Stock. In connection with this redemption, the Aimco Operating Partnership redeemed from Aimco a corresponding number of Partnership Preferred Units. Redeemable Preferred OP Units In addition to the Partnership Preferred Units owned by Aimco, the Aimco Operating Partnership has outstanding various classes of redeemable Partnership Preferred Units owned by third parties, which we refer to as preferred OP Units. As of December 31, 2018 and 2017 , 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 2018 2017 2018 2017 Class One 8.75 % $ 8.00 90,000 90,000 $ 8,229 $ 8,229 Class Two 1.92 % $ 0.48 14,240 17,750 356 444 Class Three 7.88 % $ 1.97 1,338,524 1,338,524 33,463 33,462 Class Four 8.00 % $ 2.00 644,954 644,954 16,124 16,124 Class Six 8.50 % $ 2.13 773,693 780,036 19,342 19,501 Class Seven 7.87 % $ 1.97 27,960 27,960 699 699 Class Nine 6.00 % $ 1.50 243,112 243,112 6,078 6,078 Class Ten 6.00 % $ 1.50 680,000 680,000 17,000 17,000 Total 3,812,483 3,822,336 $ 101,291 $ 101,537 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 partnership 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, 2018 , 2017 and 2016 , approximately 10,000 , 67,000 and 69,000 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. The Class Ten preferred OP Units were issued as partial consideration for an acquisition during the year ended December 31, 2016. The following table presents a reconciliation of the Aimco Operating Partnership’s preferred OP Units during the years ended December 31, 2018 , 2017 and 2016 (in thousands): 2018 2017 2016 Balance at January 1 $ 101,537 $ 103,201 $ 87,926 Preferred distributions (7,740 ) (7,764 ) (7,239 ) Redemption of preferred units and other (246 ) (1,664 ) (1,725 ) Issuance of preferred units — — 17,000 Net income 7,740 7,764 7,239 Balance at December 31 $ 101,291 $ 101,537 $ 103,201 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, 2018 , 2017 and 2016 , approximately 224,000 , 268,000 and 248,000 common OP Units, respectively, were redeemed in exchange for cash, and no common OP Units were redeemed in exchange for shares of Common Stock. 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, 2018 , 2017 and 2016 , the Aimco Operating Partnership declared distributions per common unit of $1.52 , $1.44 and $1.32 , respectively On February 3, 2019, the Board of Directors of the Aimco Operating Partnership’s general partner authorized a reverse unit split in which every 1.03119 common partnership units will be combined into one common partnership unit. The reverse split is effective at the close of business on February 20, 2019, and corresponds to a similar split effected by Aimco with respect to its common shares at the same time. On the same date, the Board of Directors also declared a special distribution to the holders of Aimco Operating Partnership common partnership units that consists of $71.5 million in cash and 4.8 million common partnership units. The special distribution will be payable on March 22, 2019, to unitholders of record as of February 22, 2019. The special distribution also corresponds to a similar special dividend paid at the same time to holders of Aimco common shares. The reverse split was authorized in order to neutralize the dilutive impact of the units issued in the special distribution. As a result, total common partnership units outstanding following completion of both the special distribution and the reverse unit split are expected to be unchanged from the total common partnership units outstanding immediately prior to the transactions. Pro forma Earnings per Common Unit (Unaudited) In financial statements issued after the effective date of the reverse unit split, we are required to retroactively recognize the reverse unit split in the calculation of basic and diluted earnings per unit. The units issued in connection with the special distribution will be included in the calculation of basic and diluted earnings per unit on a prospective basis, and are therefore not included in the pro forma amounts disclosed below. If the reverse unit split had been effective prior to issuance of these financial statements, basic and diluted weighted average units outstanding and earnings per unit for the years ending December 31, 2018, 2017 and 2016 would have been (units in thousands): 2018 2017 2016 Weighted average units, basic 158,890 158,793 158,808 Weighted average units, diluted 159,073 159,257 159,194 Basic earnings per unit $ 4.35 $ 2.02 $ 2.76 Diluted earnings per unit $ 4.34 $ 2.02 $ 2.75

Share-Based Compensation

Share-Based Compensation	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Share-Based Compensation	Share-Based Compensation We have a stock award and incentive program to attract and retain officers and independent directors. As of December 31, 2018 , approximately 4.7 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 be increased by an additional 0.3 million shares to the extent of 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 stock based awards was $9.7 million , $9.3 million and $8.6 million for the years ended December 31, 2018 , 2017 and 2016 , respectively. Of these amounts, $1.2 million , $1.4 million and $1.0 million , respectively, were capitalized. At December 31, 2018 , total unvested compensation cost not yet recognized was $11.0 million . We expect to recognize this compensation over a weighted average period of approximately 1.6 years . We have granted five different types of awards that are outstanding as of December 31, 2018 . We have outstanding 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 have outstanding 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 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 ten 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. The term of Time-Based Stock Options and TSR Stock Options is generally ten 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. Stock Options During the years ended December 31, 2018 , 2017 and 2016, we granted TSR Stock Options. The following table summarizes activity for our outstanding stock options, for the years ended December 31, 2018 , 2017 and 2016 (options in thousands): 2018 2017 2016 Number of Options Weighted Number of Options Weighted Number of Options Weighted Outstanding at beginning of year 648 $ 40.08 675 $ 29.55 1,394 $ 30.85 Granted — — 184 44.07 216 38.73 Exercised (2 ) 28.33 (211 ) 9.90 (934 ) 33.61 Forfeited — — — — (1 ) 29.11 Outstanding at end of year 646 $ 40.12 648 $ 40.08 675 $ 29.55 Exercisable at end of year 186 $ 38.18 128 $ 37.59 280 $ 16.38 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, 2018 , options outstanding had an aggregate intrinsic value of $2.5 million and a weighted average remaining contractual term of 7.0 years . Options exercisable at December 31, 2018 , had an aggregate intrinsic value of $1.1 million and a weighted average remaining contractual term of 5.9 years . The intrinsic value of stock options exercised during the years ended December 31, 2018 , 2017 and 2016 , was $32 thousand , $7.1 million and $11.1 million , respectively. The weighted average grant date fair value of stock options granted during the years ended 2017 and 2016 was $11.39 and $9.94 per option, respectively. Time-Based Restricted Stock Awards The following table summarizes activity for Time-Based Restricted Stock awards for the years ended December 31, 2018 , 2017 and 2016 (shares in thousands): 2018 2017 2016 Number of Shares Weighted Number of Shares Weighted Number of Shares Weighted Unvested at beginning of year 160 $ 37.63 249 $ 33.61 339 $ 29.96 Granted 51 40.01 45 44.07 91 40.03 Vested (86 ) 34.42 (134 ) 32.35 (181 ) 29.99 Unvested at end of year 125 $ 40.82 160 $ 37.63 249 $ 33.61 The aggregate fair value of shares that vested during the years ended December 31, 2018 , 2017 and 2016 was $8.4 million , $6.0 million and $7.0 million , respectively. TSR Restricted Stock Awards The following table summarizes activity for TSR Restricted Stock awards for the years ended December 31, 2018 , 2017 and 2016 (shares in thousands): 2018 2017 2016 Number of Shares Weighted Number of Shares Weighted Number of Shares Weighted Unvested at beginning of year 253 $ 40.70 214 $ 39.66 123 $ 39.72 Granted 45 41.71 39 46.39 91 39.59 Vested (123 ) 39.72 — — — — Unvested at end of year 175 $ 41.65 253 $ 40.70 214 $ 39.66 TSR LTIP I Units The following table summarizes activity for TSR LTIP I units for the years ended December 31, 2018 and 2017 (units in thousands): 2018 2017 Number of Units Weighted Number of Units Weighted Unvested at beginning of year 45 $ 46.21 — $ — Granted 48 41.48 45 46.21 Unvested at end of year 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, 2018 and 2017 (numbers of units in thousands): 2018 Number of Units Weighted Unvested at beginning of year — $ — Granted 243 41.84 Unvested at end of year 243 $ 41.84 Determination of Grant-Date Fair Value of Awards We estimated the fair value of TSR-based awards granted in 2018 , 2017 and 2016 using a Monte Carlo model using the assumptions set forth in the table below. The risk-free interest rate reflects the annualized yield of a zero coupon U.S. Treasury security with a term equal to the expected term of the option. 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 options 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 option exercises and post-vesting terminations. The midpoints of our valuation assumptions for the 2018 , 2017 and 2016 grants were as follows: 2018 2017 2016 Grant date market value of a common share $ 40.95 $ 44.07 $ 38.73 Risk-free interest rate 2.32 % 1.57 % 1.15 % Dividend yield 3.52 % 3.27 % 3.41 % Expected volatility 18.02 % 21.33 % 21.24 % 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 5.6 years 5.8 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, 2018
Income Tax Disclosure [Abstract]
Income Taxes	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, 2018 2017 Deferred tax liabilities: Real estate and real estate partnership basis differences $ 12,058 $ 32,032 Deferred tax assets: Net operating, capital and other loss carryforwards $ 7,022 $ 9,523 Accruals and expenses 7,432 6,575 Tax credit carryforwards 67,530 73,450 Management contracts and other 2,064 200 Total deferred tax assets 84,048 89,748 Valuation allowance (4,930 ) (25,489 ) Net deferred tax assets $ 67,060 $ 32,227 In December 2017, the U.S. Congress passed the Tax Cuts and Jobs Act, or the 2017 Act, which is effective for years beginning with 2018. The 2017 Act provided for a reduction in the federal income tax rate. In accordance with GAAP, we revalued our deferred tax assets and liabilities as of December 31, 2017. We finalized our accounting for the tax effects of enactment of the 2017 Act during the year ended December 31, 2018, resulting in our recognition of a cumulative net tax benefit of $15.6 million over the two years. At December 31, 2018 , we had federal and state net operating loss carryforwards, or NOLs, for which the deferred tax asset was approximately $7.0 million , before a valuation allowance of $4.9 million . The NOLs expire in years 2019 to 2034 . 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, 2018 , we had low-income housing and rehabilitation tax credit carryforwards and corresponding deferred tax assets of approximately $67.5 million for income tax purposes that expire in years 2034 to 2038 . In light of the lower federal tax rate under the 2017 Act, our TRS entities must generate more taxable income in future years to utilize tax credit carryforwards, which are recorded as deferred tax assets. As a result, during the year ended December 31, 2017, we recognized a partial valuation allowance of $15.4 million against the deferred tax assets associated with low-income housing and rehabilitation tax credit carryforwards. Due to the sale of our Asset Management business, discussed further in Note 3 , during the year ended December 31, 2018, we reversed the remaining valuation allowance recognized in 2017 against our deferred tax benefits that we now expect to utilize. A reconciliation of the beginning and ending balance of our unrecognized tax benefits is presented below (in thousands): 2018 2017 2016 Balance at January 1 $ 2,476 $ 2,286 $ 2,897 Additions (reductions) based on tax positions related to prior years 142 190 (611 ) Balance at December 31 $ 2,618 $ 2,476 $ 2,286 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 remains in process as of December 31, 2018 . We do not believe the audit will have any material effect on our unrecognized 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 income before gain on dispositions and gain on dispositions of real estate, net of tax, in our consolidated statements of operations for the years ended December 31, 2018 , 2017 and 2016 (in thousands): 2018 2017 2016 Current: Federal $ 11,269 $ (938 ) $ 5,038 State 10,537 525 2,916 Total current 21,806 (413 ) 7,954 Deferred: Federal (29,243 ) (10,908 ) (26,173 ) State (5,590 ) (3,621 ) (623 ) Revaluation of deferred taxes due to change in tax rate — (15,894 ) — Total deferred (34,833 ) (30,423 ) (26,796 ) Total benefit $ (13,027 ) $ (30,836 ) $ (18,842 ) 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, 2018 , 2017 and 2016 , we had consolidated net income subject to tax of $158.6 million , net loss subject to tax of $55.6 million and net income subject to tax of $109.3 million , respectively. 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): 2018 2017 2016 Amount Percent Amount Percent Amount Percent Tax provision (benefit) at United States statutory rates on consolidated income or loss subject to tax $ 33,296 21.0 % $ (19,459 ) 35.0 % $ 38,257 35.0 % State income tax expense, net of federal tax (benefit) expense 12,252 7.7 % (1,769 ) 3.2 % 7,152 6.5 % Establishment of deferred tax asset related to partnership basis difference (1) — — % (3,501 ) 6.3 % — — % Effect of permanent differences 302 0.2 % (1,629 ) 2.9 % (132 ) (0.1 )% Tax effect of intercompany transactions (2) (33,250 ) (21.0 )% — — % (47,369 ) (43.3 )% Tax credits (6,897 ) (4.4 )% (9,607 ) 17.3 % (16,750 ) (15.3 )% Tax reform revaluation (3) 288 0.2 % (15,894 ) 28.6 % — — % (Decrease) increase in valuation allowance (4) (20,434 ) (12.9 )% 21,023 (37.8 )% — — % Other 1,416 0.9 % — — % — — % Total income tax benefit $ (13,027 ) (8.3 )% $ (30,836 ) 55.5 % $ (18,842 ) (17.2 )% (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) 2016 includes the effect of intercompany asset transfers between the Aimco Operating Partnership and TRS entities, for which tax was deferred and recognized as the assets affected GAAP income or loss, for example, through depreciation, impairment, or upon the sale of the asset to a third-party. 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) 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 $11.5 million , $7.4 million and $2.2 million in the years ended December 31, 2018 , 2017 and 2016 , 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, 2018 , 2017 and 2016 , dividends per share held for the entire year were estimated to be taxable as follows: 2018 2017 2016 Amount Percentage Amount Percentage Amount Percentage Ordinary income $ 0.51 33.4 % $ 0.75 51.5 % $ 0.45 34.2 % Capital gains 0.93 61.2 % 0.51 35.7 % 0.47 35.4 % Qualified dividends — — % 0.02 1.6 % 0.13 9.9 % Unrecaptured Section 1250 gain 0.08 5.4 % 0.16 11.2 % 0.27 20.5 % $ 1.52 100.0 % $ 1.44 100.0 % $ 1.32 100.0 %

Earnings per Share_Unit

Earnings per Share/Unit	12 Months Ended
	Dec. 31, 2018
Earnings Per Share [Abstract]
Earnings per Share/Unit	Earnings per Share/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 and participating securities outstanding, and 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 equivalents 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 the issuance of additional common shares and common partnership units equal to the number of shares that vest. The dilutive effect of these securities was 0.2 million shares or units, 0.5 million shares or units, and 0.4 million shares or units, respectively, for the years ended December 31, 2018 , 2017 and 2016 . Securities with dilutive effect are included in the denominator for calculating diluted earnings per share and unit during these periods. There were 0.3 million potential shares and 0.3 million potential units not dilutive and excluded from the denominator for calculating diluted earnings per share and per unit, respectively, for the year ended December 31, 2018 . There were 0.2 million potential shares and 0.2 million potential units not dilutive and excluded from the denominator for calculating diluted earnings per share and per unit, respectively, for the years ended December 31, 2017 and 2016 . Our Time-Based Restricted Stock awards receive 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 distributions based on specified percentages of the distributions paid to common partnership units prior to vesting and conversion. These dividends and distributions are not forfeited in the event the awards do not vest. Therefore, the unvested restricted shares and units related to these awards are participating securities. The effect of participating securities is included 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. At December 31, 2018 , 2017 and 2016 , there were 0.3 million , 0.2 million and 0.2 million shares of unvested participating restricted securities, respectively. At December 31, 2018 , 2017 and 2016 , there were 0.6 million , 0.3 million and 0.2 million units of unvested participating restricted securities, respectively. 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, 2018 , these preferred OP Units were potentially redeemable for approximately 2.3 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, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	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 we classify as AFS debt securities. These investments are presented within other assets in the accompanying consolidated balance sheets. We hold several positions in the securitization trust that pay interest currently and we also hold the first loss position in the securitization trust, which accrues interest over the term of the investment. These investments were acquired at a discount to face value and we are accreting the discount to the $100.9 million face value of the investments through interest income using the effective interest method over the remaining expected term of the investments, which as of December 31, 2018 , was approximately 2.4 years. Our amortized cost basis for these investments, which represents the original cost adjusted for interest accretion less interest payments received, was $83.6 million and $77.7 million at December 31, 2018 and 2017 , respectively. We estimated the fair value of these investments to be $88.5 million and $82.8 million at December 31, 2018 and 2017 , respectively. Our investments in AFS debt securities are classified within Level 2 of the GAAP fair value hierarchy. We estimate the fair value of these investments using an income and market approach with primarily observable inputs, including yields and other information regarding similar types of investments, and adjusted for certain unobservable inputs specific to these investments. The fair value of the positions that pay interest currently typically moves in an inverse relationship with movements in interest rates. The fair value of the first loss position is primarily correlated to collateral quality and demand for similar subordinate commercial mortgage-backed securities. Fair Value Disclosures We believe that the carrying values of the consolidated amounts of cash and cash equivalents, receivables and payables approximates their fair value at December 31, 2018 and 2017 , due to their relatively short-term nature and high probability of realization. The carrying amount of seller financing notes receivable approximated their estimated fair value at December 31, 2018 . The carrying amount of the total indebtedness associated with our Real Estate portfolio approximated its estimated fair value at December 31, 2018 and 2017 . We estimate the fair value of our seller financing notes and our consolidated 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 debt and seller financing notes within Level 3 of the GAAP valuation hierarchy based on the significance of certain of the unobservable inputs used to estimate its fair value.

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Business Segments	Business Segments Our chief executive officer, who is 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 revenue less our share of property operating expenses, including real estate taxes, for consolidated apartment communities we own and manage. Beginning in 2018, we exclude from rental and other property revenues the amount of utilities cost reimbursed by residents and reflect such amount as a reduction of the related utility expense within property operating expenses in our evaluation of segment results. In our consolidated statements of operation, utility reimbursements are included in rental and other property revenues, in accordance with GAAP. The 2017 and 2016 tables below have been revised to conform to this presentation. Apartment communities are classified as either part of our Real Estate portfolio or, prior to the sale in July 2018, those owned through partnerships served by our Asset Management business. As of December 31, 2018 , for segment performance evaluation, our Real Estate segment included 130 consolidated apartment communities with 36,407 apartment homes and excluded four apartment communities with 142 apartment homes that we neither manage nor consolidate. Prior to the July 2018 sale of our Asset Management business, we consolidated certain partnerships in which we held nominal positions. These partnerships own low-income housing tax credit apartment communities. Neither the results of operations nor the assets of these partnerships and apartment communities were quantitatively material during our period of ownership; therefore, we have one reportable segment, Real Estate. The following tables present the revenues, net operating income and income before gain on dispositions of our Real Estate segment on a proportionate basis and excluding amounts related to apartment communities sold or classified as held for sale as of December 31, 2018 for the years ended December 31, 2018 , 2017 and 2016 (in thousands): Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Reportable Segment (2) Consolidated Year Ended December 31, 2018: Rental and other property revenues attributable to Real Estate $ 854,240 $ 34,282 $ 34,071 $ 922,593 Rental and other property revenues of partnerships served by Asset Management business — — 42,830 42,830 Tax credit and transaction revenues — — 6,987 6,987 Total revenues 854,240 34,282 83,888 972,410 Property operating expenses attributable to Real Estate 238,860 32,169 36,872 307,901 Property operating expenses of partnerships served by Asset Management business — — 20,921 20,921 Other operating expenses not allocated to reportable segment (3) — — 427,832 427,832 Total operating expenses 238,860 32,169 485,625 756,654 Proportionate property net operating income 615,380 — — — Other items included in income before income tax benefit (4) — — 487,820 487,820 Income before income tax benefit $ 615,380 $ 2,113 $ 86,083 $ 703,576 Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Reportable Segment (2) Consolidated Year Ended December 31, 2017: Rental and other property revenues attributable to Real Estate $ 781,194 $ 43,043 $ 93,911 $ 918,148 Rental and other property revenues of partnerships served by Asset Management business — — 74,046 74,046 Tax credit and transaction revenues — — 13,243 13,243 Total revenues 781,194 43,043 181,200 1,005,437 Property operating expenses attributable to Real Estate 222,731 32,432 63,963 319,126 Property operating expenses of partnerships served by Asset Management business — — 35,458 35,458 Other operating expenses not allocated to reportable segment (3) — — 456,870 456,870 Total operating expenses 222,731 32,432 556,291 811,454 Proportionate property net operating income 558,463 — — — Other items included in income before income tax benefit (4) — — 122,260 122,260 Income before income tax benefit $ 558,463 $ 10,611 $ (252,831 ) $ 316,243 Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Reportable Segment (2) Consolidated Year Ended December 31, 2016: Rental and other property revenues attributable to Real Estate $ 720,302 $ 55,257 $ 124,332 $ 899,891 Rental and other property revenues of partnerships served by Asset Management business — — 74,640 74,640 Tax credit and transaction revenues — — 21,323 21,323 Total revenues 720,302 55,257 220,295 995,854 Property operating expenses attributable to Real Estate 210,426 35,468 72,063 317,957 Property operating expenses of partnerships served by Asset Management business — — 36,956 36,956 Other operating expenses not allocated to reportable segment (3) — — 394,145 394,145 Total operating expenses 210,426 35,468 503,164 749,058 Proportionate property net operating income 509,876 — — — Other items included in income before income tax benefit (4) — — 217,635 217,635 Income before income tax benefit $ 509,876 $ 19,789 $ (65,234 ) $ 464,431 (1) Represents adjustments for the noncontrolling interests in consolidated real estate partnerships’ share of the results of consolidated apartment communities in our Real Estate segment, which are included in the related consolidated amounts, but excluded from proportionate property net operating income for our segment evaluation. Also includes the reclassification of utility reimbursements from revenues to property operating expenses for the purpose of evaluating segment results. Utility reimbursements are included in rental and other property revenues in our 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 apartment communities owned by consolidated partnerships served by our Asset Management business prior to its sale in July 2018. Corporate and Amounts Not Allocated to Reportable Segment 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 reportable segment consists of 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 interest expense. The assets of our reportable segment and the consolidated assets not allocated to our segment are as follows (in thousands): December 31, 2018 2017 Real Estate $ 5,849,638 $ 5,346,390 Corporate and other assets (1) 340,366 732,650 Total consolidated assets $ 6,190,004 $ 6,079,040 (1) Includes the assets not allocated to our reportable segment, primarily corporate assets, and assets of apartment communities and the Asset Management business, which were sold or classified as held for sale as of December 31, 2018 . For the years ended December 31, 2018 , 2017 and 2016 , capital additions related to our Real Estate segment totaled $338.8 million , $321.9 million and $312.8 million , respectively.

Variable Interest Entities

Variable Interest Entities	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	Variable Interest Entities Generally, a variable interest entity, or VIE, is a legal entity in which the equity investors do not have the characteristics of a controlling financial interest or the equity investors lack sufficient equity at risk for the entity to finance its activities without additional subordinated financial support. A limited partnership is considered a VIE when the majority of the limited partners unrelated to the general partner possess neither the right to remove the general partner without cause, nor certain rights to participate in the decisions that most significantly affect the financial results of the partnership. In determining whether we are the primary beneficiary of a VIE, we consider qualitative and quantitative factors, including, but not limited to: which activities most significantly impact the VIE’s economic performance and which party controls such activities; the amount and characteristics of our investment; the obligation or likelihood for us or other investors to provide financial support; and the similarity with and significance to our business activities and the business activities of the other investors. Significant judgments related to these determinations include estimates about the current and future fair values and performance of real estate held by these VIEs and general market conditions. Aimco consolidates the Aimco Operating Partnership, which is a VIE for which Aimco is the primary beneficiary. Aimco, through the Aimco Operating Partnership, consolidates all VIEs for which it is the primary beneficiary. All of the VIEs we consolidate own interests in one or more apartment communities. VIEs that own apartment communities we classify as part of our Real Estate segment are typically structured to generate a return for their partners through the operation and ultimate sale of the communities. We are the primary beneficiary in the limited partnerships in which we are the sole decision maker and have a substantial economic interest. As described in Note 3 , we sold our Asset Management business in July 2018, including the nominal ownership interest we held in partnerships served by this business. December 31, 2018 2017 Real Estate portfolio: VIEs with interests in apartment communities 9 14 Apartment communities owned by VIEs 9 14 Apartment homes in communities owned by VIEs 3,592 4,321 Consolidated partnerships served by the Asset Management business: VIEs with interests in apartment communities — 49 Apartment communities owned by VIEs — 37 Apartment homes in communities owned by VIEs — 5,893 Assets of the Aimco Operating Partnership’s consolidated VIEs must first be used to settle the liabilities of such consolidated VIEs. These consolidated VIEs’ creditors do not have recourse to the general credit of the Aimco Operating Partnership. Assets and liabilities of VIEs are summarized in the table below (in thousands): December 31, 2018 2017 Real Estate portfolio: Assets Net real estate $ 488,127 $ 529,898 Cash and cash equivalents 15,416 16,111 Restricted cash 4,461 4,798 Liabilities Non-recourse property debt 322,685 412,205 Accrued liabilities and other 13,576 10,623 Consolidated partnerships served by the Asset Management business: Assets Real estate, net — 215,580 Cash and cash equivalents — 15,931 Restricted cash — 30,107 Liabilities Non-recourse property debt — 220,356 Accrued liabilities and other — 20,241

Unaudited Summarized Consolidat

Unaudited Summarized Consolidated Quarterly Information	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Unaudited Summarized Consolidated Quarterly Information	Unaudited Summarized Consolidated Quarterly Information Aimco Aimco’s summarized unaudited consolidated quarterly information for the years ended December 31, 2018 and 2017 , is provided below (in thousands, except per share amounts): 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 $ 0.52 $ 0.02 $ 3.62 $ 0.03 Net income attributable to Aimco common stockholders per common share - diluted $ 0.52 $ 0.02 $ 3.61 $ 0.03 Quarter 2017 First Second Third Fourth Total revenues $ 246,481 $ 249,092 $ 254,635 $ 255,229 Net income 17,155 21,591 22,144 286,189 Net income attributable to Aimco common stockholders 11,491 15,843 17,430 262,097 Net income attributable to Aimco common stockholders per common share - basic $ 0.07 $ 0.10 $ 0.11 $ 1.68 Net income attributable to Aimco common stockholders per common share - diluted $ 0.07 $ 0.10 $ 0.11 $ 1.67 The Aimco Operating Partnership The Aimco Operating Partnership’s summarized unaudited consolidated quarterly information for the years ended December 31, 2018 and 2017 , is provided below (in thousands, except per unit amounts): 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 $ 0.52 $ 0.02 $ 3.62 $ 0.03 Net income attributable to the Partnership’s common unitholders per common unit - diluted $ 0.52 $ 0.02 $ 3.61 $ 0.03 Quarter 2017 First Second Third Fourth Total revenues $ 246,481 $ 249,092 $ 254,635 $ 255,229 Net income 17,155 21,591 22,144 286,189 Net income attributable to the Partnership’s common unitholders 12,047 16,627 18,246 274,380 Net income attributable to the Partnership’s common unitholders per common unit - basic $ 0.07 $ 0.10 $ 0.11 $ 1.68 Net income attributable to the Partnership’s common unitholders per common unit - diluted $ 0.07 $ 0.10 $ 0.11 $ 1.67

Real Estate and Accumulated Dep

Real Estate and Accumulated Depreciation	12 Months Ended
	Dec. 31, 2018
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III: Real Estate and Accumulated Depreciation Disclosure	APARTMENT INVESTMENT AND MANAGEMENT COMPANY AIMCO PROPERTIES, L.P. SCHEDULE III: REAL ESTATE AND ACCUMULATED DEPRECIATION December 31, 2018 (In Thousands Except Apartment Home Data) (2) (1) Initial Cost Cost Capitalized December 31, 2018 Apartment Date Year Apartment Buildings and Subsequent to Buildings and (3) Accumulated Total Cost (4) Apartment Community Name Type Consolidated Location Built Homes Land Improvements Consolidation Land Improvements Total Depreciation (AD) Net of AD Encumbrances Real Estate Segment: 100 Forest Place High Rise Dec 1997 Oak Park, IL 1987 234 $ 2,664 $ 18,815 $ 10,553 $ 2,664 $ 29,368 $ 32,032 $ (15,640 ) $ 16,392 $ 35,048 118-122 West 23rd Street High Rise Jun 2012 New York, NY 1987 42 14,985 23,459 6,752 14,985 30,211 45,196 (9,121 ) 36,075 17,457 173 E. 90th Street High Rise May 2004 New York, NY 1910 72 12,066 4,535 8,068 12,066 12,603 24,669 (3,730 ) 20,939 — 182-188 Columbus Avenue Mid Rise Feb 2007 New York, NY 1910 32 19,123 3,300 5,513 19,123 8,813 27,936 (3,968 ) 23,968 13,925 1045 on the Park Apartments Homes Mid Rise Jul 2013 Atlanta, GA 2012 30 2,793 6,662 692 2,793 7,354 10,147 (1,423 ) 8,724 5,627 1582 First Avenue High Rise Mar 2005 New York, NY 1900 17 4,281 752 499 4,281 1,251 5,532 (578 ) 4,954 2,273 21 Fitzsimons Mid Rise Aug 2014 Aurora, CO 2008 600 12,864 104,720 20,379 12,864 125,099 137,963 (19,590 ) 118,373 90,000 234 East 88th Street Mid Rise Jan 2014 New York, NY 1900 20 2,448 4,449 807 2,448 5,256 7,704 (1,154 ) 6,550 3,223 236-238 East 88th Street High Rise Jan 2004 New York, NY 1900 43 8,820 2,914 2,681 8,820 5,595 14,415 (1,930 ) 12,485 10,875 237-239 Ninth Avenue High Rise Mar 2005 New York, NY 1900 36 8,495 1,866 3,092 8,495 4,958 13,453 (2,770 ) 10,683 5,553 240 West 73rd Street, LLC High Rise Sep 2004 New York, NY 1900 200 68,109 12,140 11,905 68,109 24,045 92,154 (9,818 ) 82,336 — 2900 on First Apartments Mid Rise Oct 2008 Seattle, WA 1989 135 19,070 17,518 33,542 19,070 51,060 70,130 (25,554 ) 44,576 13,915 306 East 89th Street High Rise Jul 2004 New York, NY 1930 20 2,680 1,006 1,098 2,680 2,104 4,784 (888 ) 3,896 1,854 311 & 313 East 73rd Street Mid Rise Mar 2003 New York, NY 1904 34 5,678 1,609 520 5,678 2,129 7,807 (1,487 ) 6,320 3,904 322-324 East 61st Street High Rise Mar 2005 New York, NY 1900 40 6,372 2,224 1,512 6,372 3,736 10,108 (1,830 ) 8,278 3,410 3400 Avenue of the Arts Mid Rise Mar 2002 Costa Mesa, CA 1987 770 57,241 65,506 80,349 57,241 145,855 203,096 (86,923 ) 116,173 145,752 452 East 78th Street High Rise Jan 2004 New York, NY 1900 12 1,982 608 548 1,982 1,156 3,138 (486 ) 2,652 2,542 464-466 Amsterdam & 200-210 W. 83rd Street Mid Rise Feb 2007 New York, NY 1910 71 25,553 7,101 6,070 25,553 13,171 38,724 (6,031 ) 32,693 20,520 510 East 88th Street High Rise Jan 2004 New York, NY 1900 20 3,163 1,002 622 3,163 1,624 4,787 (642 ) 4,145 2,724 514-516 East 88th Street High Rise Mar 2005 New York, NY 1900 36 6,282 2,168 1,593 6,282 3,761 10,043 (1,619 ) 8,424 3,696 518 East 88th Street Mid Rise Jan 2014 New York, NY 1900 20 2,233 4,315 606 2,233 4,921 7,154 (1,137 ) 6,017 2,792 707 Leahy Garden Apr 2007 Redwood City, CA 1973 110 15,444 7,909 7,406 15,444 15,315 30,759 (6,964 ) 23,795 8,737 777 South Broad Street Mid Rise May 2018 Philadelphia, PA 2010 146 6,986 67,512 829 6,986 68,341 75,327 (1,515 ) 73,812 57,627 865 Bellevue Garden Jul 2000 Nashville, TN 1972 326 3,562 12,037 23,538 3,562 35,575 39,137 (23,393 ) 15,744 — Avery Row Mid Rise Dec 2018 Arlington, VA 2013 67 8,140 21,348 — 8,140 21,348 29,488 — 29,488 — Axiom Mid Rise Apr 2015 Cambridge, MA 2015 115 — 63,612 2,444 — 66,056 66,056 (8,920 ) 57,136 32,978 Bank Lofts High Rise Apr 2001 Denver, CO 1920 125 3,525 9,045 5,539 3,525 14,584 18,109 (7,463 ) 10,646 10,476 Bay Parc Plaza High Rise Sep 2004 Miami, FL 2000 474 22,680 41,847 34,053 22,680 75,900 98,580 (22,485 ) 76,095 42,434 Bay Ridge at Nashua Garden Jan 2003 Nashua, NH 1984 412 3,262 40,713 16,739 3,262 57,452 60,714 (22,738 ) 37,976 51,450 Bayberry Hill Estates Garden Aug 2002 Framingham, MA 1971 424 19,944 35,945 21,847 19,944 57,792 77,736 (27,629 ) 50,107 — Bent Tree Apartments Garden Feb 2018 Centreville, VA 1986 748 46,975 113,695 7,493 46,975 121,188 168,163 (4,331 ) 163,832 — Bluffs at Pacifica, The Garden Oct 2006 Pacifica, CA 1963 64 8,108 4,132 17,804 8,108 21,936 30,044 (10,996 ) 19,048 — Boston Lofts High Rise Apr 2001 Denver, CO 1890 158 3,446 20,589 5,694 3,446 26,283 29,729 (13,914 ) 15,815 15,303 Boulder Creek Garden Jul 1994 Boulder, CO 1973 221 754 7,730 20,628 754 28,358 29,112 (19,702 ) 9,410 38,500 Broadcast Center Garden Mar 2002 Los Angeles, CA 1990 279 29,407 41,244 28,683 29,407 69,927 99,334 (29,655 ) 69,679 — Broadway Lofts High Rise Sep 2012 San Diego, CA 1909 84 5,367 14,442 6,126 5,367 20,568 25,935 (4,604 ) 21,331 11,531 Burke Shire Commons Garden Mar 2001 Burke, VA 1986 360 4,867 23,617 17,678 4,867 41,295 46,162 (24,737 ) 21,425 57,860 (2) (1) Initial Cost Cost Capitalized December 31, 2018 Apartment Date Year Apartment Buildings and Subsequent to Buildings and (3) Accumulated Total Cost (4) Apartment Community Name Type Consolidated Location Built Homes Land Improvements Consolidation Land Improvements Total Depreciation (AD) Net of AD Encumbrances Calhoun Beach Club High Rise Dec 1998 Minneapolis, MN 1928 332 11,708 73,334 64,948 11,708 138,282 149,990 (79,547 ) 70,443 — Canyon Terrace Garden Mar 2002 Saugus, CA 1984 130 7,508 6,601 6,525 7,508 13,126 20,634 (6,960 ) 13,674 — Cedar Rim Garden Apr 2000 Newcastle, WA 1980 104 761 5,218 13,032 761 18,250 19,011 (13,153 ) 5,858 — Charlesbank Apartment Homes Mid Rise Sep 2013 Watertown, MA 2012 44 3,399 11,726 821 3,399 12,547 15,946 (2,404 ) 13,542 7,718 Chestnut Hall High Rise Oct 2006 Philadelphia, PA 1923 315 12,338 14,299 12,074 12,338 26,373 38,711 (12,144 ) 26,567 36,653 Chimneys of Cradle Rock Garden Jun 2004 Columbia, MD 1979 198 2,040 8,108 1,116 2,040 9,224 11,264 (4,206 ) 7,058 — Columbus Avenue Mid Rise Sep 2003 New York, NY 1880 59 35,527 9,450 9,117 35,527 18,567 54,094 (10,600 ) 43,494 25,205 Creekside Garden Jan 2000 Denver, CO 1974 328 3,189 12,698 7,450 3,189 20,148 23,337 (13,072 ) 10,265 11,325 Crescent at West Hollywood, The Mid Rise Mar 2002 West Hollywood, CA 1985 130 15,765 10,215 8,411 15,765 18,626 34,391 (12,166 ) 22,225 40,000 Elm Creek Mid Rise Dec 1997 Elmhurst, IL 1987 400 5,910 30,830 31,950 5,910 62,780 68,690 (32,993 ) 35,697 51,341 Evanston Place High Rise Dec 1997 Evanston, IL 1990 190 3,232 25,546 16,214 3,232 41,760 44,992 (19,152 ) 25,840 — Farmingdale Mid Rise Oct 2000 Darien, IL 1975 240 11,763 15,174 11,173 11,763 26,347 38,110 (13,618 ) 24,492 13,106 Flamingo Towers High Rise Sep 1997 Miami Beach, FL 1960 1,324 32,427 48,808 339,187 32,427 387,995 420,422 (174,249 ) 246,173 103,152 Four Quarters Habitat Garden Jan 2006 Miami, FL 1976 336 2,379 17,199 30,286 2,379 47,485 49,864 (27,112 ) 22,752 51,603 Foxchase Garden Dec 1997 Alexandria, VA 1940 2,113 15,496 96,062 52,254 15,496 148,316 163,812 (85,298 ) 78,514 223,626 Georgetown Garden Aug 2002 Framingham, MA 1964 207 12,351 13,168 3,996 12,351 17,164 29,515 (8,281 ) 21,234 14,697 Georgetown II Mid Rise Aug 2002 Framingham, MA 1958 72 4,577 4,057 2,118 4,577 6,175 10,752 (3,483 ) 7,269 — Heritage Park Escondido Garden Oct 2000 Escondido, CA 1986 196 1,055 7,565 2,572 1,055 10,137 11,192 (6,993 ) 4,199 6,129 Heritage Park Livermore Garden Oct 2000 Livermore, CA 1988 167 — 10,209 1,850 — 12,059 12,059 (8,176 ) 3,883 6,353 Heritage Village Anaheim Garden Oct 2000 Anaheim, CA 1986 196 1,832 8,541 2,084 1,832 10,625 12,457 (6,999 ) 5,458 7,441 Hidden Cove Garden Jul 1998 Escondido, CA 1983 334 3,043 17,616 10,802 3,043 28,418 31,461 (16,205 ) 15,256 51,840 Hidden Cove II Garden Jul 2007 Escondido, CA 1986 118 12,849 6,530 5,260 12,849 11,790 24,639 (5,263 ) 19,376 20,160 Hillcreste Garden Mar 2002 Century City, CA 1989 315 35,862 47,216 13,194 35,862 60,410 96,272 (27,374 ) 68,898 63,479 Hillmeade Garden Nov 1994 Nashville, TN 1986 288 2,872 16,070 20,200 2,872 36,270 39,142 (21,006 ) 18,136 27,321 Horizons West Apartments Mid Rise Dec 2006 Pacifica, CA 1970 78 8,887 6,377 1,634 8,887 8,011 16,898 (3,689 ) 13,209 — Hunt Club Garden Sep 2000 Gaithersburg, MD 1986 336 17,859 13,149 14,154 17,859 27,303 45,162 (16,083 ) 29,079 — Hyde Park Tower High Rise Oct 2004 Chicago, IL 1990 155 4,731 14,927 12,334 4,731 27,261 31,992 (9,569 ) 22,423 12,620 Indian Oaks Garden Mar 2002 Simi Valley, CA 1986 254 24,523 15,801 11,246 24,523 27,047 51,570 (13,180 ) 38,390 27,596 Indigo High Rise Aug 2016 Redwood City, CA 2016 463 26,932 296,116 1,771 26,932 297,887 324,819 (24,707 ) 300,112 138,430 Island Club Garden Oct 2000 Oceanside, CA 1986 592 18,027 28,654 18,740 18,027 47,394 65,421 (30,320 ) 35,101 94,967 Key Towers High Rise Apr 2001 Alexandria, VA 1964 140 1,526 7,050 7,781 1,526 14,831 16,357 (11,892 ) 4,465 — Lakeside Garden Oct 1999 Lisle, IL 1972 568 5,840 27,937 22,408 5,840 50,345 56,185 (33,582 ) 22,603 25,090 Latrobe High Rise Jan 2003 Washington, DC 1980 175 3,459 9,103 12,715 3,459 21,818 25,277 (11,916 ) 13,361 26,758 Laurel Crossing Garden Jan 2006 San Mateo, CA 1971 418 49,474 17,756 14,166 49,474 31,922 81,396 (15,757 ) 65,639 — Lincoln Place (5) Garden Oct 2004 Venice, CA 1951 795 128,332 10,439 337,267 44,197 347,706 391,903 (121,677 ) 270,226 187,723 Locust on the Park High Rise May 2018 Philadelphia, PA 1911 152 5,292 53,823 2,474 5,292 56,297 61,589 (1,183 ) 60,406 35,728 Lodge at Chattahoochee, The Garden Oct 1999 Sandy Springs, GA 1970 312 2,335 16,370 16,809 2,335 33,179 35,514 (22,375 ) 13,139 — Malibu Canyon Garden Mar 2002 Calabasas, CA 1986 698 69,834 53,438 37,919 69,834 91,357 161,191 (45,222 ) 115,969 105,367 Mariners Cove Garden Mar 2002 San Diego, CA 1984 500 — 66,861 13,317 — 80,178 80,178 (39,035 ) 41,143 — Meadow Creek Garden Jul 1994 Boulder, CO 1968 332 1,435 24,533 9,602 1,435 34,135 35,570 (19,285 ) 16,285 — Merrill House High Rise Jan 2000 Falls Church, VA 1964 159 1,836 10,831 7,657 1,836 18,488 20,324 (10,492 ) 9,832 — Mezzo High Rise Mar 2015 Atlanta, GA 2008 94 4,292 34,178 1,250 4,292 35,428 39,720 (5,484 ) 34,236 23,496 Monterey Grove Garden Jun 2008 San Jose, CA 1999 224 34,325 21,939 8,674 34,325 30,613 64,938 (12,039 ) 52,899 — Ocean House on Prospect Mid Rise Apr 2013 La Jolla, CA 1970 53 12,528 18,805 15,089 12,528 33,894 46,422 (6,592 ) 39,830 12,745 One Canal High Rise Sep 2013 Boston, MA 2016 310 — 15,873 179,912 — 195,785 195,785 (20,623 ) 175,162 110,310 Pacific Bay Vistas (5) Garden Mar 2001 San Bruno, CA 1987 308 28,694 62,460 39,067 23,354 101,527 124,881 (35,131 ) 89,750 67,826 Pacifica Park Garden Jul 2006 Pacifica, CA 1977 104 12,970 6,579 7,879 12,970 14,458 27,428 (6,565 ) 20,863 28,613 (2) (1) Initial Cost Cost Capitalized December 31, 2018 Apartment Date Year Apartment Buildings and Subsequent to Buildings and (3) Accumulated Total Cost (4) Apartment Community Name Type Consolidated Location Built Homes Land Improvements Consolidation Land Improvements Total Depreciation (AD) Net of AD Encumbrances Palazzo at Park La Brea, The Mid Rise Feb 2004 Los Angeles, CA 2002 521 48,362 125,464 45,176 48,362 170,640 219,002 (80,075 ) 138,927 168,654 Palazzo East at Park La Brea, The Mid Rise Mar 2005 Los Angeles, CA 2005 611 72,578 136,503 19,328 72,578 155,831 228,409 (72,709 ) 155,700 196,109 Parc Mosaic Garden Dec 2014 Boulder, CO 1970 226 15,300 — 53,638 15,300 53,638 68,938 — 68,938 — Park Towne Place High Rise Apr 2000 Philadelphia, PA 1959 940 10,472 47,301 345,748 10,472 393,049 403,521 (119,350 ) 284,171 200,000 Pathfinder Village Garden Jan 2006 Fremont, CA 1973 246 19,595 14,838 18,457 19,595 33,295 52,890 (14,518 ) 38,372 55,000 Peachtree Park Garden Jan 1996 Atlanta, GA 1969 303 4,684 11,713 14,045 4,684 25,758 30,442 (16,449 ) 13,993 27,800 Plantation Gardens Garden Oct 1999 Plantation, FL 1971 372 3,773 19,443 25,655 3,773 45,098 48,871 (27,273 ) 21,598 — Post Ridge Garden Jul 2000 Nashville, TN 1972 150 1,883 6,712 4,537 1,883 11,249 13,132 (7,401 ) 5,731 — Preserve at Marin Mid Rise Aug 2011 Corte Madera, CA 1964 126 18,179 30,132 84,629 18,179 114,761 132,940 (26,039 ) 106,901 36,260 Ravensworth Towers High Rise Jun 2004 Annandale, VA 1974 219 3,455 17,157 4,490 3,455 21,647 25,102 (14,617 ) 10,485 20,342 River Club,The Garden Apr 2005 Edgewater, NJ 1998 266 30,579 30,638 7,475 30,579 38,113 68,692 (17,293 ) 51,399 60,000 Riverloft High Rise Oct 1999 Philadelphia, PA 1910 184 2,120 11,286 35,086 2,120 46,372 48,492 (23,386 ) 25,106 7,680 Rosewood Garden Mar 2002 Camarillo, CA 1976 152 12,430 8,060 5,754 12,430 13,814 26,244 (6,984 ) 19,260 — Royal Crest Estates Garden Aug 2002 Warwick, RI 1972 492 22,433 24,095 5,512 22,433 29,607 52,040 (20,050 ) 31,990 — Royal Crest Estates Garden Aug 2002 Nashua, NH 1970 902 68,230 45,562 15,751 68,230 61,313 129,543 (41,440 ) 88,103 71,957 Royal Crest Estates Garden Aug 2002 Marlborough, MA 1970 473 25,178 28,786 13,490 25,178 42,276 67,454 (26,610 ) 40,844 — Royal Crest Estates Garden Aug 2002 North Andover, MA 1970 588 51,292 36,808 27,916 51,292 64,724 116,016 (36,132 ) 79,884 — Saybrook Point Garden Dec 2014 San Jose, CA 1995 324 32,842 84,457 25,729 32,842 110,186 143,028 (14,179 ) 128,849 62,329 Shenandoah Crossing Garden Sep 2000 Fairfax, VA 1984 640 18,200 57,198 25,345 18,200 82,543 100,743 (58,302 ) 42,441 58,565 SouthStar Lofts High Rise May 2018 Philadelphia, PA 2014 85 1,780 37,428 402 1,780 37,830 39,610 (836 ) 38,774 30,197 Springwoods at Lake Ridge Garden Jul 2002 Woodbridge, VA 1984 180 5,587 7,284 3,642 5,587 10,926 16,513 (4,606 ) 11,907 — St. George Villas Garden Jan 2006 St. George, SC 1984 40 107 1,025 410 107 1,435 1,542 (1,256 ) 286 314 Sterling Apartment Homes, The Garden Oct 1999 Philadelphia, PA 1961 534 8,871 55,365 120,426 8,871 175,791 184,662 (82,367 ) 102,295 144,030 Stone Creek Club Garden Sep 2000 Germantown, MD 1984 240 13,593 9,347 8,078 13,593 17,425 31,018 (12,553 ) 18,465 — The Left Bank Mid Rise May 2018 Philadelphia, PA 1929 282 — 130,893 3,053 — 133,946 133,946 (2,879 ) 131,067 82,532 Timbers at Long Reach Apartment Homes Garden Apr 2005 Columbia, MD 1979 178 2,430 12,181 1,705 2,430 13,886 16,316 (8,182 ) 8,134 — Towers Of Westchester Park, The High Rise Jan 2006 College Park, MD 1972 303 15,198 22,029 13,936 15,198 35,965 51,163 (18,825 ) 32,338 23,232 Township At Highlands Town Home Nov 1996 Centennial, CO 1985 161 1,536 9,773 9,280 1,536 19,053 20,589 (12,181 ) 8,408 13,557 Tremont Mid Rise Dec 2014 Atlanta, GA 2009 78 5,274 18,011 2,746 5,274 20,757 26,031 (3,110 ) 22,921 — Twin Lake Towers High Rise Oct 1999 Westmont, IL 1969 399 3,268 18,763 37,904 3,268 56,667 59,935 (43,106 ) 16,829 44,906 Vantage Pointe Mid Rise Aug 2002 Swampscott, MA 1987 96 4,748 10,089 2,314 4,748 12,403 17,151 (5,294 ) 11,857 2,746 Villa Del Sol Garden Mar 2002 Norwalk, CA 1972 120 7,476 4,861 4,553 7,476 9,414 16,890 (5,216 ) 11,674 10,582 Villas at Park La Brea, The Garden Mar 2002 Los Angeles, CA 2002 250 8,630 48,871 16,008 8,630 64,879 73,509 (30,510 ) 42,999 53,868 Villas of Pasadena Mid Rise Jan 2006 Pasadena, CA 1973 92 9,693 6,818 4,493 9,693 11,311 21,004 (4,397 ) 16,607 — Vivo High Rise Jun 2016 Cambridge, MA 2015 91 6,450 35,974 5,590 6,450 41,564 48,014 (8,694 ) 39,320 20,310 Waterford Village Garden Aug 2002 Bridgewater, MA 1971 588 29,110 28,101 8,222 29,110 36,323 65,433 (26,540 ) 38,893 35,269 Waterways Village Garden Jun 1997 Aventura, FL 1994 180 4,504 11,064 15,205 4,504 26,269 30,773 (12,394 ) 18,379 13,168 Waverly Apartments Garden Aug 2008 Brighton, MA 1970 103 7,920 11,347 6,299 7,920 17,646 25,566 (6,323 ) 19,243 11,515 Wexford Village Garden Aug 2002 Worcester, MA 1974 264 6,349 17,939 4,245 6,349 22,184 28,533 (12,980 ) 15,553 — Willow Bend Garden May 1998 Rolling Meadows, IL 1969 328 2,717 15,437 19,609 2,717 35,046 37,763 (23,492 ) 14,271 33,175 Windrift Garden Mar 2001 Oceanside, CA 1987 404 24,960 17,590 21,487 24,960 39,077 64,037 (23,762 ) 40,275 — Windsor Park Garden Mar 2001 Woodbridge, VA 1987 220 4,279 15,970 6,217 4,279 22,187 26,466 (13,378 ) 13,088 — Yacht Club at Brickell High Rise Dec 2003 Miami, FL 1998 357 31,362 32,214 16,715 31,362 48,929 80,291 (17,513 ) 62,778 44,219 Yorktown Apartments High Rise Dec 1999 Lombard, IL 1971 364 3,055 18,162 52,436 3,055 70,598 73,653 (29,697 ) 43,956 38,280 Other (6) — 5,135 — 20,914 5,135 20,914 26,049 — 26,049 — Total Real Estate Segment 35,625 1,846,000 3,494,014 3,058,051 1,756,525 6,552,065 8,308,590 (2,585,115 ) 5,723,475 3,937,000 (2) (1) Initial Cost Cost Capitalized December 31, 2018 Apartment Date Year Apartment Buildings and Subsequent to Buildings and (3) Accumulated Total Cost (4) Apartment Community Name Type Consolidated Location Built Homes Land Improvements Consolidation Land Improvements Total Depreciation (AD) Net of AD Encumbrances (1) Date we acquired the apartment community or first consolidated the partnership that owns the apartment community. (2) Includes costs capitalized since acquisition or date of initial consolidation of the partnership/apartment community. (3) The aggregate cost of land and depreciable property for federal income tax purposes was approximately $4.0 billion at December 31, 2018. (4) Encumbrances are presented before reduction for debt issuance costs. (5) The current carrying value of the apartment community reflects an impairment loss recognized during prior periods. (6) Other includes 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, 2018 , 2017 and 2016 (In Thousands) 2018 2017 2016 Real Estate Segment Real Estate balance at beginning of year $ 7,927,753 $ 7,931,117 $ 7,744,894 Additions during the year: Acquisitions 501,009 16,687 333,174 Capital additions 344,501 345,974 329,697 Deductions during the year: Casualty and other write-offs (1) (58,152 ) (106,590 ) (170,744 ) Impairment of real estate — (35,881 ) — Amounts related to assets held for sale (83,905 ) (38,208 ) — Sales (322,616 ) (185,346 ) (305,904 ) Real Estate balance at end of year $ 8,308,590 $ 7,927,753 $ 7,931,117 Accumulated Depreciation balance at beginning of year $ 2,522,358 $ 2,421,357 $ 2,488,448 Additions during the year: Depreciation 339,883 320,870 287,661 Deductions during the year: Casualty and other write-offs (1) (57,067 ) (106,521 ) (169,098 ) Amounts related to assets held for sale (41,717 ) (20,383 ) — Sales (178,342 ) (92,965 ) (185,654 ) Accumulated depreciation balance at end of year $ 2,585,115 $ 2,522,358 $ 2,421,357 Asset Management Business Real Estate balance at beginning of year $ 551,124 $ 555,049 $ 562,589 Additions during the year: Capital additions 4,226 8,255 8,909 Deductions during the year: Casualty and other write-offs (2) 6,603 (1,711 ) (2,116 ) Amounts related to assets held for sale — — (2,801 ) Sales (561,953 ) (10,469 ) (11,532 ) Real Estate balance at end of year $ — $ 551,124 $ 555,049 Accumulated Depreciation balance at beginning of year $ 326,251 $ 309,401 $ 289,574 Additions during the year: Depreciation 14,325 24,090 24,704 Deductions during the year: Casualty and other write-offs (2) 6,704 (2,480 ) (68 ) Amounts related to assets held for sale — — (1,525 ) Sales (347,280 ) (4,760 ) (3,284 ) Accumulated depreciation balance at end of year $ — $ 326,251 $ 309,401 (1) Includes the write-off of fully depreciated assets totaling $54.5 million , $106.4 million and $167.9 million , during the years ended December 31, 2018 , 2017 and 2016 , respectively. (2) Includes the write-off of fully depreciated assets totaling $6.7 million and $1.8 million , during the years ended December 31, 2018 and 2017 , respectively.

Basis of Presentation and Sum_2

Basis of Presentation and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
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 (see Note 13 ). All significant intercompany balances have been eliminated in consolidation. Interests in the Aimco Operating Partnership that are held by limited partners other than Aimco are reflected in Aimco’s accompanying consolidated balance sheets as noncontrolling interests in Aimco Operating Partnership. Interests in partnerships consolidated by the Aimco Operating Partnership that are held by third parties are reflected in our accompanying consolidated balance sheets as noncontrolling interests in consolidated real estate partnerships. 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. 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.
Acquisition of Real Estate and Related Depreciation and Amortization	Acquisition of Real Estate and Related Depreciation and Amortization We generally recognize the acquisition of apartment communities or interests in partnerships that own apartment communities at our cost. The related transaction costs are included in the cost of the acquired apartment community. We allocate the cost of apartment communities acquired based on the relative fair value of the assets acquired and liabilities assumed. 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. 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 apartment community. At December 31, 2018 , the weighted average depreciable life of our buildings and improvements was approximately 28 years. Furniture, fixtures and equipment associated with apartment communities are depreciated over five years. 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.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets 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 make an assessment of its recoverability by comparing the carrying amount to our estimate of the undiscounted future cash flows, excluding interest charges, of the apartment 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 apartment community.
Cash Equivalents	Cash Equivalents We classify highly liquid investments with an original maturity of three months or less as cash equivalents. We maintain cash equivalents in financial institutions in excess of insured limits. We have not experienced any losses in these accounts in the past and believe that we are not exposed to significant credit risk because our accounts are deposited with major financial institutions.
Restricted Cash	Restricted Cash Restricted cash includes capital replacement reserves, completion repair reserves, bond sinking fund amounts, tax and insurance escrow accounts held by lenders and resident security deposits.
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 recognized by and related to such entities, and we present such amounts within other, net in our consolidated statements of operations. The excess of the cost of the acquired partnership interests over the historical carrying amount of partners’ equity or deficit is generally ascribed to the fair values of land and buildings owned by the partnerships. We amortize the excess cost related 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. 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.
Intangible Assets	Intangible Assets At December 31, 2018 and 2017 , other assets included goodwill associated with our reportable segment of $37.8 million . We perform an annual impairment test of goodwill by evaluating qualitative factors to determine the likelihood that goodwill may be impaired. We primarily consider the fair value of our real estate portfolio and the fair value of our debt relative to their carrying values. As a result of the qualitative analysis, we do not believe our goodwill is impaired as of the date of our annual test.
Capitalized Software Costs	Capitalized Software Costs, Equipment and Leasehold Improvements 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.
Equipment and Leasehold Improvements	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.
Deferred Costs	Deferred Costs We defer, as debt issue 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 issue costs over the term of the modified loan agreement. Debt issue costs associated with our revolving credit facility are included in other assets on our consolidated balance sheets. Debt issue costs associated with non-recourse property debt and our term loan are presented as a direct deduction from the related liabilities on our consolidated balance sheets. When financing arrangements are repaid or otherwise extinguished prior to maturity, unamortized debt issue costs are written off, additionally, any lender fees or other costs incurred in connection with the extinguishment are recognized. Amortization and write-off of debt issue costs and other extinguishment costs are included in interest expense on our consolidated statements of operations. We defer leasing commissions and other direct costs incurred in connection with successful leasing efforts and amortize the costs over the terms of the related leases. Beginning in 2019, in connection with our adoption of the new accounting standard for leases, which is further discussed under the Recent Accounting Pronouncements heading below, such costs will be deferred when they are incremental and would not have incurred if the contract had not been obtained. Amortization of these costs is included in depreciation and amortization.
Noncontrolling Interests in Consolidated Real Estate Partnerships	Noncontrolling Interests in Consolidated Real Estate Partnerships We 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. 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, 2018 , 2017 and 2016 , 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 on disposition 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.
Noncontrolling Interests in Aimco Operating Partnership	Noncontrolling Interests in Aimco Operating Partnership Noncontrolling interests in Aimco Operating Partnership consist of common OP Units and preferred OP Units. 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 partnership units based on the weighted average number of common partnership units (including those held by Aimco) outstanding during the period.
Revenue from Leases	Revenue from Leases Our apartment communities have operating leases with apartment residents with terms averaging 13 months. We recognize rental revenue related to these leases, net of any concessions, on a straight-line basis over the term of the lease. Our operating leases with residents 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 are variable payments pursuant to the related lease and recognized as income when the utility expense is incurred. 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 on our consolidated statements of operations.
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 recognized income from asset management and other services when the related fees were earned and realized or realizable. The tax credits were generally realized ratably over the first ten years of the tax credit arrangement and are subject to the partnership’s compliance with applicable laws and regulations for a period of 15 years . We held nominal ownership positions in these partnerships, generally less than one percent, and sold these interests to an unrelated third party in July 2018. In our role, we provided asset management and other services to these partnerships and we received fees and other payments in return. Capital contributions received by the partnerships from tax credit investors represented, in substance, consideration that we received in exchange for our obligation to deliver tax credits and other tax benefits to the investors. We recorded these contributions as deferred income in our consolidated balance sheets upon receipt, and we recognized these amounts as revenue in our consolidated statements of operations when our obligation to the investors is relieved upon delivery of the tax benefits. This obligation transferred to the buyer along with our interest in the partnerships. Prior to the sale of our interests in the partnerships, we consolidated the low-income housing tax credit partnerships in which we were the sole general partner, because we were the sole decision maker of the partnerships. When the contractual arrangements obligated us to deliver tax benefits to the investors, and entitled us through fee arrangements to receive substantially all available cash flow from the partnerships, we recognized the income or loss generated by the underlying real estate based on our economic interest in the partnerships’ current period results, which was approximately 100% and represented the allocation of cash available for distribution we would receive from a hypothetical liquidation at the book value of the partnership’s net assets. Our economic interests generally differed from our legal interests. Upon the sale of our interests in these partnerships, we deconsolidated these partnerships and removed the obligation to deliver future tax credits and benefits, represented by the remaining deferred income as a component of our gain on the sale of the business.
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. See Note 8 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 our 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.
Comprehensive Income or Loss	Comprehensive Income or Loss As discussed under the preceding Investments in Securitization Trust that holds Aimco Property Debt heading, we have investments in debt securities that are measured at fair value with unrealized gains or losses recognized as an adjustment of accumulated other comprehensive loss within equity and partners’ capital. Additionally, during the year ended December 31, 2018 , we recognized changes in the fair value of our cash flow hedges as an adjustment of accumulated other comprehensive loss within equity and partners’ capital until the July 2018 sale of the Asset Management business. The amounts of consolidated comprehensive income for the years ended December 31, 2018 , 2017 and 2016 , along with the corresponding amounts of such comprehensive income attributable to Aimco, the Aimco Operating Partnership and to noncontrolling interests, are presented within the accompanying consolidated statements of comprehensive income.
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.
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	Reclassifications Certain items included in the 2017 and 2016 consolidated financial statements have been reclassified to conform to the current presentation. We have also reclassified certain items on our consolidated statements of operations to comply with the SEC disclosure amendments summarized below.
Accounting Pronouncements Adopted in the Current Year	Accounting Pronouncements Adopted in the Current Year Effective January 1, 2018, we adopted a new standard issued by the Financial Accounting Standards Board, or FASB, that affects accounting for revenue. Under this new standard, revenue is generally recognized when an entity has transferred control of goods or services to a customer for an amount reflecting the consideration to which the entity expects to be entitled for such exchange. The new revenue standard also introduced new guidance for accounting for other income, including how we measure gains or losses on the sale of real estate. We adopted the new standard using the modified retrospective transition method effective January 1, 2018, with no effect on our results of operations or financial position. Effective January 1, 2018, we also adopted new standards issued by the FASB that affect the presentation and disclosure of the statements of cash flows. We are now required to present combined inflows and outflows of cash, cash equivalents, and restricted cash in the consolidated statement of cash flows. Previously our consolidated statements of cash flows presented transfers between restricted and unrestricted cash accounts as operating, financing and investing cash activities depending on the required or intended purpose for the restricted funds. The new guidance also requires debt prepayment and other extinguishment-related payments to be classified as financing activities. We previously classified such payments as operating activities. We have revised our consolidated statements of cash flows for the years ended December 31, 2017 and 2016 to conform to this presentation, and the effect of the revisions to net cash flows from operating, investing, and financing activities as previously reported are summarized in the following table (in thousands): 2017 2016 As Previously Reported Adjustments As Revised As Previously Reported Adjustments As Revised Net cash provided by operating activities $ 394,139 $ (2,067 ) $ 392,072 $ 377,724 $ (1,223 ) $ 376,501 Net cash used in investing activities 14,704 (1,685 ) 13,019 (97,773 ) (1,374 ) (99,147 ) Net cash used in financing activities (393,301 ) (399 ) (393,700 ) (269,496 ) (14,453 ) (283,949 ) 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 and were generally effective on November 5, 2018. The amendments remove the SEC rule that requires REITs to present gain or loss on the sale of real estate, net of income tax, in the statement of operations. Consistent with the SEC’s historical requirements, we previously presented gain or loss on dispositions of real estate below continuing operations and net of tax. For the year ended December 31, 2018, we present gain on dispositions of real estate as a component of income before income taxes in our consolidated statements of operations and we have revised the 2017 and 2016 comparative periods to conform to this presentation as follows: 2017 2016 As Previously Reported Adjustments As Revised As Previously Reported Adjustments As Revised Income tax benefit 32,126 (1,290 ) 30,836 25,208 (6,366 ) 18,842 Gain on dispositions of real estate 299,559 1,290 300,849 393,790 6,366 400,156 Additionally, SEC rules previously required changes in equity subsequent to the prior year-end as either a separate financial statement or in the notes to interim financial statements. For interim periods in 2018, we presented changes in equity within a footnote to our interim condensed consolidated financial statements in accordance with the SEC rule. The amendments create a requirement to report changes in equity and dividends per share in interim periods on a comparative basis for both quarter-to-date and year-to-date periods presented. This disclosure is required for interim financial statements beginning in 2019; therefore, we will present comparative interim statements of stockholders equity beginning in our condensed consolidated financial statements for the three months ending March 31, 2019.
Recent Accounting Pronouncements	Recent Accounting Pronouncements The FASB issued a new standard on lease accounting, which is effective for us on January 1, 2019. Under the new lease standard, lessor accounting will be largely unchanged and lessees will be required to recognize a lease liability and related right of use asset for all leases with terms longer than 12 months, with such leases classified as either operating or finance. The standard may be adopted utilizing multiple practical expedients, and we plan to adopt the standard using all practical expedients that aid in calculating the value of the lease liability and related right of use asset on the date of adoption, as well as the prospective practical expedient that allows lessors to combine lease and nonlease components where the timing and pattern of transfer are the same. We do not anticipate significant changes in the timing of income recognition from our leases with residents. However, in circumstances where we are a lessee, in primarily a limited population of ground leases and leases for corporate office space, we will be required to recognize lease liabilities and related right of use assets on our consolidated balance sheets. We anticipate recording lease liabilities and related right of use assets in amounts less than 1.5% of total assets as of December 31, 2018. Additionally, our adoption of the standard will affect the manner in which we recognize costs incurred to obtain resident leases. Through December 31, 2018, we deferred certain costs based on the percentage of successful leases relative to all leasing candidates. Under the new standard, only costs that are contingent upon a signed lease may be deferred. We do not anticipate recording significant cumulative catch up adjustments in connection with our adoption of this standard.
Fair Value of Financial Instruments	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. 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 we classify as AFS debt securities

Basis of Presentation and Sum_3

Basis of Presentation and Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Estimated aggregate amortization of below-market leases	At December 31, 2018 , our below-market leases had a weighted average amortization period of 6.3 years and estimated aggregate amortization for each of the five succeeding years as follows (in thousands): Estimated Amortization 2019 $1,986 2020 1,741 2021 1,668 2022 1,621 2023 1,571
Other assets	At December 31, 2018 and 2017 , other assets was comprised of the following amounts (dollars in thousands): 2018 2017 Investments in securitization trust that holds Aimco property debt $ 83,587 $ 82,794 Deferred tax asset, net (Note 9) 67,060 32,227 Intangible assets, net 43,424 38,701 Prepaid expenses, real estate taxes and insurance 25,657 25,144 Software, equipment and leasehold improvements 18,309 20,048 Investments in unconsolidated real estate partnerships 12,650 12,636 Accounts and notes receivable, net 55,630 17,035 Deferred costs, deposits and other 45,224 44,154 Total other assets $ 351,541 $ 272,739
Accounting pronouncements adopted in the current year	For the year ended December 31, 2018, we present gain on dispositions of real estate as a component of income before income taxes in our consolidated statements of operations and we have revised the 2017 and 2016 comparative periods to conform to this presentation as follows: 2017 2016 As Previously Reported Adjustments As Revised As Previously Reported Adjustments As Revised Income tax benefit 32,126 (1,290 ) 30,836 25,208 (6,366 ) 18,842 Gain on dispositions of real estate 299,559 1,290 300,849 393,790 6,366 400,156 We have revised our consolidated statements of cash flows for the years ended December 31, 2017 and 2016 to conform to this presentation, and the effect of the revisions to net cash flows from operating, investing, and financing activities as previously reported are summarized in the following table (in thousands): 2017 2016 As Previously Reported Adjustments As Revised As Previously Reported Adjustments As Revised Net cash provided by operating activities $ 394,139 $ (2,067 ) $ 392,072 $ 377,724 $ (1,223 ) $ 376,501 Net cash used in investing activities 14,704 (1,685 ) 13,019 (97,773 ) (1,374 ) (99,147 ) Net cash used in financing activities (393,301 ) (399 ) (393,700 ) (269,496 ) (14,453 ) (283,949 )

Significant Transactions (Table

Significant Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Business Combinations [Abstract]
Summarized information regarding acquisitions	Summarized information regarding these acquisitions is set forth in the table below (dollars in thousands): 2018 Number of apartment communities 6 Number of apartment homes 1,480 Purchase price (1) $ 483,066 Capitalized transaction costs 7,591 Total fair value allocated to land 69,177 Total fair value allocated to building and improvements 424,718 Total fair value allocated to intangible assets 9,700 Total fair value allocated to intangible liabilities 12,938 (1) The gross purchase price of the Philadelphia portfolio consisted of $34.4 million in cash, $208.9 million of assumed property-level debt and the issuance of 1.2 million OP Units. In accordance with GAAP, the OP Units were valued at $41.08 per unit, the closing price of Aimco’s common share on May 1, 2018, the purchase date.
Summarized information regarding apartment communities sold	In addition to the Hunters Point apartment communities, we sold the following apartment communities from our Real Estate portfolio during the years ended December 31, 2018 , 2017 and 2016 (dollars in thousands): 2018 2017 2016 Real Estate portfolio: Apartment communities sold 4 5 7 Apartment homes sold 1,334 2,291 3,045 Gain on dispositions of real estate $ 175,213 $ 297,730 $ 383,647

Non-Recourse Property Debt an_2

Non-Recourse Property Debt and Credit Agreement (Tables)	12 Months Ended
	Dec. 31, 2018
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 at December 31, 2018 and 2017 (in thousands): 2018 2017 Fixed-rate property debt $ 3,676,882 $ 3,480,378 Variable-rate property debt 260,118 82,663 Debt issue costs, net of accumulated amortization (21,695 ) (17,932 ) Non-recourse property debt, net $ 3,915,305 $ 3,545,109
Scheduled principal amortization and maturity payments for non-recourse debt related to apartment communities classified as held for use	As of December 31, 2018 , the scheduled principal amortization and maturity payments for the non-recourse property debt related to apartment communities classified as held for use were as follows (in thousands): Amortization Maturities 2019 $ 77,791 $ 168,554 2020 79,592 78,930 2021 (1) 69,995 611,039 2022 64,991 283,629 2023 55,450 337,871 Thereafter 2,109,158 Total $ 3,937,000 (1) Pursuant to the terms of our loan agreements, we may prepay in 2020 $246.5 million of loans maturing in 2021, without penalty.

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies Disclosure [Abstract]
Approximate minimum annual rentals under operating lease obligations and sublease receivables	Minimum annual rental payments under operating leases are as follows (in thousands): Office Lease Obligations Ground Lease Obligations Total Operating Lease Obligations 2019 $ 2,237 $ 2,114 $ 4,351 2020 2,821 2,350 5,171 2021 2,719 2,439 5,158 2022 2,582 2,492 5,074 2023 1,871 2,492 4,363 Thereafter 10,644 422,169 432,813 Total $ 22,874 $ 434,056 $ 456,930

Aimco Equity (Tables)

Aimco Equity (Tables)	12 Months Ended
	Dec. 31, 2018
Equity [Abstract]
Pro forma earnings per share	If the reverse stock split had been effective prior to issuance of these financial statements, basic and diluted weighted average shares outstanding and earnings per share for the years ending December 31, 2018, 2017 and 2016 would have been (shares in thousands): 2018 2017 2016 Weighted average shares, basic 151,152 151,595 151,282 Weighted average shares, diluted 151,334 152,060 151,669 Basic earnings per share $ 4.34 $ 2.02 $ 2.76 Diluted earnings per share $ 4.34 $ 2.02 $ 2.75 If the reverse unit split had been effective prior to issuance of these financial statements, basic and diluted weighted average units outstanding and earnings per unit for the years ending December 31, 2018, 2017 and 2016 would have been (units in thousands): 2018 2017 2016 Weighted average units, basic 158,890 158,793 158,808 Weighted average units, diluted 159,073 159,257 159,194 Basic earnings per unit $ 4.35 $ 2.02 $ 2.76 Diluted earnings per unit $ 4.34 $ 2.02 $ 2.75

Partners' Capital (Tables)

Partners' Capital (Tables)	12 Months Ended
	Dec. 31, 2018
Partners' Capital [Abstract]
Classes of preferred OP Units	As of December 31, 2018 and 2017 , 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 2018 2017 2018 2017 Class One 8.75 % $ 8.00 90,000 90,000 $ 8,229 $ 8,229 Class Two 1.92 % $ 0.48 14,240 17,750 356 444 Class Three 7.88 % $ 1.97 1,338,524 1,338,524 33,463 33,462 Class Four 8.00 % $ 2.00 644,954 644,954 16,124 16,124 Class Six 8.50 % $ 2.13 773,693 780,036 19,342 19,501 Class Seven 7.87 % $ 1.97 27,960 27,960 699 699 Class Nine 6.00 % $ 1.50 243,112 243,112 6,078 6,078 Class Ten 6.00 % $ 1.50 680,000 680,000 17,000 17,000 Total 3,812,483 3,822,336 $ 101,291 $ 101,537
Reconciliation of preferred OP Units	The following table presents a reconciliation of the Aimco Operating Partnership’s preferred OP Units during the years ended December 31, 2018 , 2017 and 2016 (in thousands): 2018 2017 2016 Balance at January 1 $ 101,537 $ 103,201 $ 87,926 Preferred distributions (7,740 ) (7,764 ) (7,239 ) Redemption of preferred units and other (246 ) (1,664 ) (1,725 ) Issuance of preferred units — — 17,000 Net income 7,740 7,764 7,239 Balance at December 31 $ 101,291 $ 101,537 $ 103,201
Pro forma earnings per unit	If the reverse stock split had been effective prior to issuance of these financial statements, basic and diluted weighted average shares outstanding and earnings per share for the years ending December 31, 2018, 2017 and 2016 would have been (shares in thousands): 2018 2017 2016 Weighted average shares, basic 151,152 151,595 151,282 Weighted average shares, diluted 151,334 152,060 151,669 Basic earnings per share $ 4.34 $ 2.02 $ 2.76 Diluted earnings per share $ 4.34 $ 2.02 $ 2.75 If the reverse unit split had been effective prior to issuance of these financial statements, basic and diluted weighted average units outstanding and earnings per unit for the years ending December 31, 2018, 2017 and 2016 would have been (units in thousands): 2018 2017 2016 Weighted average units, basic 158,890 158,793 158,808 Weighted average units, diluted 159,073 159,257 159,194 Basic earnings per unit $ 4.35 $ 2.02 $ 2.76 Diluted earnings per unit $ 4.34 $ 2.02 $ 2.75

Share-Based Compensation (Table

Share-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of activity for outstanding stock options	The following table summarizes activity for our outstanding stock options, for the years ended December 31, 2018 , 2017 and 2016 (options in thousands): 2018 2017 2016 Number of Options Weighted Number of Options Weighted Number of Options Weighted Outstanding at beginning of year 648 $ 40.08 675 $ 29.55 1,394 $ 30.85 Granted — — 184 44.07 216 38.73 Exercised (2 ) 28.33 (211 ) 9.90 (934 ) 33.61 Forfeited — — — — (1 ) 29.11 Outstanding at end of year 646 $ 40.12 648 $ 40.08 675 $ 29.55 Exercisable at end of year 186 $ 38.18 128 $ 37.59 280 $ 16.38
Summary of activity for restricted stock awards	The following table summarizes activity for Time-Based Restricted Stock awards for the years ended December 31, 2018 , 2017 and 2016 (shares in thousands): 2018 2017 2016 Number of Shares Weighted Number of Shares Weighted Number of Shares Weighted Unvested at beginning of year 160 $ 37.63 249 $ 33.61 339 $ 29.96 Granted 51 40.01 45 44.07 91 40.03 Vested (86 ) 34.42 (134 ) 32.35 (181 ) 29.99 Unvested at end of year 125 $ 40.82 160 $ 37.63 249 $ 33.61 The following table summarizes activity for TSR Restricted Stock awards for the years ended December 31, 2018 , 2017 and 2016 (shares in thousands): 2018 2017 2016 Number of Shares Weighted Number of Shares Weighted Number of Shares Weighted Unvested at beginning of year 253 $ 40.70 214 $ 39.66 123 $ 39.72 Granted 45 41.71 39 46.39 91 39.59 Vested (123 ) 39.72 — — — — Unvested at end of year 175 $ 41.65 253 $ 40.70 214 $ 39.66 The following table summarizes activity for TSR LTIP II units for the years ended December 31, 2018 and 2017 (numbers of units in thousands): 2018 Number of Units Weighted Unvested at beginning of year — $ — Granted 243 41.84 Unvested at end of year 243 $ 41.84 The following table summarizes activity for TSR LTIP I units for the years ended December 31, 2018 and 2017 (units in thousands): 2018 2017 Number of Units Weighted Number of Units Weighted Unvested at beginning of year 45 $ 46.21 — $ — Granted 48 41.48 45 46.21 Unvested at end of year 93 $ 43.78 45 $ 46.21
Assumptions used in the determination of grant-date fair value of awards	The midpoints of our valuation assumptions for the 2018 , 2017 and 2016 grants were as follows: 2018 2017 2016 Grant date market value of a common share $ 40.95 $ 44.07 $ 38.73 Risk-free interest rate 2.32 % 1.57 % 1.15 % Dividend yield 3.52 % 3.27 % 3.41 % Expected volatility 18.02 % 21.33 % 21.24 % 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 5.6 years 5.8 years 5.8 years

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 2017 Deferred tax liabilities: Real estate and real estate partnership basis differences $ 12,058 $ 32,032 Deferred tax assets: Net operating, capital and other loss carryforwards $ 7,022 $ 9,523 Accruals and expenses 7,432 6,575 Tax credit carryforwards 67,530 73,450 Management contracts and other 2,064 200 Total deferred tax assets 84,048 89,748 Valuation allowance (4,930 ) (25,489 ) Net deferred tax assets $ 67,060 $ 32,227
Reconciliation of unrecognized tax benefits	A reconciliation of the beginning and ending balance of our unrecognized tax benefits is presented below (in thousands): 2018 2017 2016 Balance at January 1 $ 2,476 $ 2,286 $ 2,897 Additions (reductions) based on tax positions related to prior years 142 190 (611 ) Balance at December 31 $ 2,618 $ 2,476 $ 2,286
Components of the provision (benefit) for income taxes	Significant components of the income tax benefit or expense are as follows and are classified within income tax benefit in income before gain on dispositions and gain on dispositions of real estate, net of tax, in our consolidated statements of operations for the years ended December 31, 2018 , 2017 and 2016 (in thousands): 2018 2017 2016 Current: Federal $ 11,269 $ (938 ) $ 5,038 State 10,537 525 2,916 Total current 21,806 (413 ) 7,954 Deferred: Federal (29,243 ) (10,908 ) (26,173 ) State (5,590 ) (3,621 ) (623 ) Revaluation of deferred taxes due to change in tax rate — (15,894 ) — Total deferred (34,833 ) (30,423 ) (26,796 ) Total benefit $ (13,027 ) $ (30,836 ) $ (18,842 )
Reconciliation of income tax attributable to continuing and discontinued 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): 2018 2017 2016 Amount Percent Amount Percent Amount Percent Tax provision (benefit) at United States statutory rates on consolidated income or loss subject to tax $ 33,296 21.0 % $ (19,459 ) 35.0 % $ 38,257 35.0 % State income tax expense, net of federal tax (benefit) expense 12,252 7.7 % (1,769 ) 3.2 % 7,152 6.5 % Establishment of deferred tax asset related to partnership basis difference (1) — — % (3,501 ) 6.3 % — — % Effect of permanent differences 302 0.2 % (1,629 ) 2.9 % (132 ) (0.1 )% Tax effect of intercompany transactions (2) (33,250 ) (21.0 )% — — % (47,369 ) (43.3 )% Tax credits (6,897 ) (4.4 )% (9,607 ) 17.3 % (16,750 ) (15.3 )% Tax reform revaluation (3) 288 0.2 % (15,894 ) 28.6 % — — % (Decrease) increase in valuation allowance (4) (20,434 ) (12.9 )% 21,023 (37.8 )% — — % Other 1,416 0.9 % — — % — — % Total income tax benefit $ (13,027 ) (8.3 )% $ (30,836 ) 55.5 % $ (18,842 ) (17.2 )% (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) 2016 includes the effect of intercompany asset transfers between the Aimco Operating Partnership and TRS entities, for which tax was deferred and recognized as the assets affected GAAP income or loss, for example, through depreciation, impairment, or upon the sale of the asset to a third-party. 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) 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.
Dividends paid to holders of Common Stock	For the years ended December 31, 2018 , 2017 and 2016 , dividends per share held for the entire year were estimated to be taxable as follows: 2018 2017 2016 Amount Percentage Amount Percentage Amount Percentage Ordinary income $ 0.51 33.4 % $ 0.75 51.5 % $ 0.45 34.2 % Capital gains 0.93 61.2 % 0.51 35.7 % 0.47 35.4 % Qualified dividends — — % 0.02 1.6 % 0.13 9.9 % Unrecaptured Section 1250 gain 0.08 5.4 % 0.16 11.2 % 0.27 20.5 % $ 1.52 100.0 % $ 1.44 100.0 % $ 1.32 100.0 %

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2018
Segment Reporting [Abstract]
Revenues, net operating income and income before gain on dispositions of Real Estate segment	The following tables present the revenues, net operating income and income before gain on dispositions of our Real Estate segment on a proportionate basis and excluding amounts related to apartment communities sold or classified as held for sale as of December 31, 2018 for the years ended December 31, 2018 , 2017 and 2016 (in thousands): Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Reportable Segment (2) Consolidated Year Ended December 31, 2018: Rental and other property revenues attributable to Real Estate $ 854,240 $ 34,282 $ 34,071 $ 922,593 Rental and other property revenues of partnerships served by Asset Management business — — 42,830 42,830 Tax credit and transaction revenues — — 6,987 6,987 Total revenues 854,240 34,282 83,888 972,410 Property operating expenses attributable to Real Estate 238,860 32,169 36,872 307,901 Property operating expenses of partnerships served by Asset Management business — — 20,921 20,921 Other operating expenses not allocated to reportable segment (3) — — 427,832 427,832 Total operating expenses 238,860 32,169 485,625 756,654 Proportionate property net operating income 615,380 — — — Other items included in income before income tax benefit (4) — — 487,820 487,820 Income before income tax benefit $ 615,380 $ 2,113 $ 86,083 $ 703,576 Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Reportable Segment (2) Consolidated Year Ended December 31, 2017: Rental and other property revenues attributable to Real Estate $ 781,194 $ 43,043 $ 93,911 $ 918,148 Rental and other property revenues of partnerships served by Asset Management business — — 74,046 74,046 Tax credit and transaction revenues — — 13,243 13,243 Total revenues 781,194 43,043 181,200 1,005,437 Property operating expenses attributable to Real Estate 222,731 32,432 63,963 319,126 Property operating expenses of partnerships served by Asset Management business — — 35,458 35,458 Other operating expenses not allocated to reportable segment (3) — — 456,870 456,870 Total operating expenses 222,731 32,432 556,291 811,454 Proportionate property net operating income 558,463 — — — Other items included in income before income tax benefit (4) — — 122,260 122,260 Income before income tax benefit $ 558,463 $ 10,611 $ (252,831 ) $ 316,243 Real Estate Proportionate and Other Adjustments (1) Corporate and Amounts Not Allocated to Reportable Segment (2) Consolidated Year Ended December 31, 2016: Rental and other property revenues attributable to Real Estate $ 720,302 $ 55,257 $ 124,332 $ 899,891 Rental and other property revenues of partnerships served by Asset Management business — — 74,640 74,640 Tax credit and transaction revenues — — 21,323 21,323 Total revenues 720,302 55,257 220,295 995,854 Property operating expenses attributable to Real Estate 210,426 35,468 72,063 317,957 Property operating expenses of partnerships served by Asset Management business — — 36,956 36,956 Other operating expenses not allocated to reportable segment (3) — — 394,145 394,145 Total operating expenses 210,426 35,468 503,164 749,058 Proportionate property net operating income 509,876 — — — Other items included in income before income tax benefit (4) — — 217,635 217,635 Income before income tax benefit $ 509,876 $ 19,789 $ (65,234 ) $ 464,431 (1) Represents adjustments for the noncontrolling interests in consolidated real estate partnerships’ share of the results of consolidated apartment communities in our Real Estate segment, which are included in the related consolidated amounts, but excluded from proportionate property net operating income for our segment evaluation. Also includes the reclassification of utility reimbursements from revenues to property operating expenses for the purpose of evaluating segment results. Utility reimbursements are included in rental and other property revenues in our 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 apartment communities owned by consolidated partnerships served by our Asset Management business prior to its sale in July 2018. Corporate and Amounts Not Allocated to Reportable Segment 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 reportable segment consists of 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 interest expense.
Assets of reportable segments and consolidated assets not allocated to segments	The assets of our reportable segment and the consolidated assets not allocated to our segment are as follows (in thousands): December 31, 2018 2017 Real Estate $ 5,849,638 $ 5,346,390 Corporate and other assets (1) 340,366 732,650 Total consolidated assets $ 6,190,004 $ 6,079,040 (1) Includes the assets not allocated to our reportable segment, primarily corporate assets, and assets of apartment communities and the Asset Management business, which were sold or classified as held for sale as of December 31, 2018 .

Variable Interest Entities (Tab

Variable Interest Entities (Tables)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	December 31, 2018 2017 Real Estate portfolio: VIEs with interests in apartment communities 9 14 Apartment communities owned by VIEs 9 14 Apartment homes in communities owned by VIEs 3,592 4,321 Consolidated partnerships served by the Asset Management business: VIEs with interests in apartment communities — 49 Apartment communities owned by VIEs — 37 Apartment homes in communities owned by VIEs — 5,893 Assets of the Aimco Operating Partnership’s consolidated VIEs must first be used to settle the liabilities of such consolidated VIEs. These consolidated VIEs’ creditors do not have recourse to the general credit of the Aimco Operating Partnership. Assets and liabilities of VIEs are summarized in the table below (in thousands): December 31, 2018 2017 Real Estate portfolio: Assets Net real estate $ 488,127 $ 529,898 Cash and cash equivalents 15,416 16,111 Restricted cash 4,461 4,798 Liabilities Non-recourse property debt 322,685 412,205 Accrued liabilities and other 13,576 10,623 Consolidated partnerships served by the Asset Management business: Assets Real estate, net — 215,580 Cash and cash equivalents — 15,931 Restricted cash — 30,107 Liabilities Non-recourse property debt — 220,356 Accrued liabilities and other — 20,241

Unaudited Summarized Consolid_2

Unaudited Summarized Consolidated Quarterly Information (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 , is provided below (in thousands, except per share amounts): 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 $ 0.52 $ 0.02 $ 3.62 $ 0.03 Net income attributable to Aimco common stockholders per common share - diluted $ 0.52 $ 0.02 $ 3.61 $ 0.03 Quarter 2017 First Second Third Fourth Total revenues $ 246,481 $ 249,092 $ 254,635 $ 255,229 Net income 17,155 21,591 22,144 286,189 Net income attributable to Aimco common stockholders 11,491 15,843 17,430 262,097 Net income attributable to Aimco common stockholders per common share - basic $ 0.07 $ 0.10 $ 0.11 $ 1.68 Net income attributable to Aimco common stockholders per common share - diluted $ 0.07 $ 0.10 $ 0.11 $ 1.67
AIMCO PROPERTIES, L.P.
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, 2018 and 2017 , is provided below (in thousands, except per unit amounts): 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 $ 0.52 $ 0.02 $ 3.62 $ 0.03 Net income attributable to the Partnership’s common unitholders per common unit - diluted $ 0.52 $ 0.02 $ 3.61 $ 0.03 Quarter 2017 First Second Third Fourth Total revenues $ 246,481 $ 249,092 $ 254,635 $ 255,229 Net income 17,155 21,591 22,144 286,189 Net income attributable to the Partnership’s common unitholders 12,047 16,627 18,246 274,380 Net income attributable to the Partnership’s common unitholders per common unit - basic $ 0.07 $ 0.10 $ 0.11 $ 1.68 Net income attributable to the Partnership’s common unitholders per common unit - diluted $ 0.07 $ 0.10 $ 0.11 $ 1.67

Organization (Details)

Organization (Details)	12 Months Ended
	Dec. 31, 2018communityPropertyapartment_homeshares
Organization [Line Items]
Common partnership units and equivalents outstanding (in shares) | shares	149,133,826
Aimco's ownership interest in AIMCO Properties, L.P.	94.30%
Number of apartment homes | community	6
Number of apartment communities	1,480
Partially Owned Properties | Aimco Real Estate
Organization [Line Items]
Number of apartment homes | Property	134
Number of apartment communities	36,549
Wholly and Partially Owned and Consolidated Properties | Aimco Real Estate
Organization [Line Items]
Number of apartment homes | Property	130
Number of apartment communities	36,407
AIMCO PROPERTIES, L.P.
Organization [Line Items]
Common partnership units and equivalents outstanding (in shares) | shares	158,140,169

Basis of Presentation and Sum_4

Basis of Presentation and Summary of Significant Accounting Policies - Acquisition of Real Estate and Related Depreciation and Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate Properties [Line Items]
Weighted average depreciable life of acquired buildings and improvements	15 years
Below market lease, net	$ 18,700	$ 9,100
Below market lease, accumulated amortization	36,700	34,400
Amortization of below market lease	2,300	$ 1,300	$ 1,700
Schedule of expected amortization of below market obligations related to acquired leases
2,019	1,986
2,020	1,741
2,021	1,668
2,022	1,621
2,023	$ 1,571
Leases, Acquired-in-Place, Market Adjustment
Real Estate Properties [Line Items]
Weighted average amortization period of below market leases	6 years 4 months
Weighted Average | Building and Building Improvements
Real Estate Properties [Line Items]
Weighted average depreciable life of acquired buildings and improvements	28 years

Basis of Presentation and Sum_5

Basis of Presentation and Summary of Significant Accounting Policies - Capital Additions and Related Depreciation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Estimated useful life	15 years
Interest costs capitalized	$ 7.6	$ 7.6	$ 9.6
Other direct and indirect costs capitalized	$ 36.8	$ 36	$ 32.9
Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life	5 years
Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life	30 years

Basis of Presentation and Sum_6

Basis of Presentation and Summary of Significant Accounting Policies - Other Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Deferred tax asset, net (Note 9)	$ 67,060	$ 32,227
Aimco Real Estate
Segment Reporting, Asset Reconciling Item [Line Items]
Investments in securitization trust that holds Aimco property debt	83,587	82,794
Deferred tax asset, net (Note 9)	67,060	32,227
Intangible assets, net	43,424	38,701
Prepaid expenses, real estate taxes and insurance	25,657	25,144
Software, equipment and leasehold improvements	18,309	20,048
Investments in unconsolidated real estate partnerships	12,650	12,636
Accounts and notes receivable, net	55,630	17,035
Deferred costs, deposits and other	45,224	44,154
Total other assets	$ 351,541	$ 272,739

Basis of Presentation and Sum_7

Basis of Presentation and Summary of Significant Accounting Policies - Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Goodwill	$ 37.8	$ 37.8

Basis of Presentation and Sum_8

Basis of Presentation and Summary of Significant Accounting Policies - Capitalized Software Costs, Equipment and Leasehold Improvements (Details)	12 Months Ended
	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of acquired equipment	15 years
Equipment
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of acquired equipment	5 years
Minimum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of software	3 years
Estimated useful life of acquired equipment	5 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Estimated useful life of software	5 years
Estimated useful life of acquired equipment	30 years

Basis of Presentation and Sum_9

Basis of Presentation and Summary of Significant Accounting Policies - Noncontrolling Interests in Aimco Operating Partnership (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Weighted average ownership interest	4.90%	4.50%	4.70%

Basis of Presentation and Su_10

Basis of Presentation and Summary of Significant Accounting Policies - Revenue from Leases (Details)	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Average term of operating leases	13 months

Basis of Presentation and Su_11

Basis of Presentation and Summary of Significant Accounting Policies - Asset Management Business (Details)	12 Months Ended
	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Term over which tax credits are generally realized	10 years
Compliance period for low income housing tax credit syndication agreements	15 years
Economic Interest in Low Income Housing Tax Credit Partnerships	approximately 100%

Basis of Presentation and Su_12

Basis of Presentation and Summary of Significant Accounting Policies - Income Taxes (Details)	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Percentage of income tax on income from non-arms length transactions	100.00%

Basis of Presentation and Su_13

Basis of Presentation and Summary of Significant Accounting Policies - Accounting Pronouncements Adopted in the Current Year (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities	$ 396,388	$ 392,072	$ 376,501
Net cash used in investing activities	121,846	13,019	(99,147)
Net cash used in financing activities	(588,180)	(393,700)	(283,949)
Income tax benefit	$ 13,027	30,836	18,842
As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		394,139	377,724
Net cash used in investing activities		14,704	(97,773)
Net cash used in financing activities		(393,301)	(269,496)
SEC Rule Change | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax benefit		32,126	25,208
Gain on dispositions of real estate and the Asset Management Business		299,559	393,790
SEC Rule Change | Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Income tax benefit		(1,290)	(6,366)
Gain on dispositions of real estate and the Asset Management Business		1,290	6,366
ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities			(1,223)
Net cash used in investing activities			(1,374)
Net cash used in financing activities			$ (14,453)
ASU 2016-18 | Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Net cash provided by operating activities		(2,067)
Net cash used in investing activities		(1,685)
Net cash used in financing activities		$ (399)

Basis of Presentation and Su_14

Basis of Presentation and Summary of Significant Accounting Policies - Recent Accounting Pronouncements (Details)	Dec. 31, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Expected total lease liabilities and right-of-use assets expected to be recorded as a percent of total assets (less than)	1.50%

Significant Transactions - Summ

Significant Transactions - Summarized Information Regarding Acquisitions (Details) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2018USD ($)communityapartment_home$ / sharesshares
Business Acquisition [Line Items]
Number of apartment homes | community	6
Number of apartment communities | apartment_home	1,480
Purchase price	$ 483,066
Capitalized transaction costs	7,591
Total fair value allocated to land	69,177
Total fair value allocated to building and improvements	424,718
Total fair value allocated to intangible assets	9,700
Total fair value allocated to intangible liabilities	12,938
Philadelphia-Area Apartment Communities
Business Acquisition [Line Items]
Cash paid in acquisition	34,400
Property-level debt assumed in acquisition	$ 208,900
OP Units issued in acquisition (in shares) | shares	1.2
Share price per unit (in dollars per share) | $ / shares	$ 41.08

Significant Transactions - Disp

Significant Transactions - Disposition of Apartment Communities and Assets Held For Sale (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2019USD ($)	Dec. 31, 2018USD ($)communityapartment_home	Dec. 31, 2017USD ($)community	Dec. 31, 2016USD ($)
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		$ 677,463	$ 300,849	$ 400,156
Number of apartment homes | community		6
Number of apartment communities | apartment_home		1,480
Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross proceeds from the sale of real estate			10,900	27,500
Gain on dispositions of real estate and the Asset Management Business			$ 2,600	$ 16,500
Number of apartment homes | community			3
Disposed of by Sale, Not Discontinued Operations | Subsequent Event
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross proceeds from the sale of real estate	$ 141,200
Gain on dispositions of real estate	87,500
Net proceeds to Aimco from the sale of real estate	$ 114,900
Held-for-sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment homes | community		2
Number of apartment communities | apartment_home		782
Wholly and Partially Owned and Consolidated Properties | Disposed of by Sale, Not Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gross proceeds from the sale of real estate		$ 590,000
Gain on dispositions of real estate and the Asset Management Business		500,300
Net proceeds to Aimco from the sale of real estate		512,200
La Jolla Cove | Wholly and Partially Owned and Consolidated Properties | Disposed of by Sale, Not Discontinued Operations
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

Significant Transactions - Su_2

Significant Transactions - Summarized Information Regarding Apartment Communities Sold (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)communityPropertyapartment_home	Dec. 31, 2017USD ($)communityPropertyapartment_home	Dec. 31, 2016USD ($)Propertyapartment_home
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment communities sold | community	6
Number of apartment homes sold | apartment_home	1,480
Gain on disposition	$ 677,463	$ 300,849	$ 400,156
Disposed of by 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		3
Gain on disposition		$ 2,600	$ 16,500
Disposed of by Sale, Not Discontinued Operations | Wholly and Partially Owned and Consolidated Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposition	$ 500,300
Aimco Real Estate | Disposed of by Sale, Not Discontinued Operations | Wholly and Partially Owned and Consolidated Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of apartment communities sold | Property	4	5	7
Number of apartment homes sold | apartment_home	1,334	2,291	3,045
Gain on disposition	$ 175,213	$ 297,730	$ 383,647

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) - Aimco Real Estate - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Non-recourse property debt	$ 3,915,305	$ 3,545,109
Debt issue costs, net of accumulated amortization	(21,695)	(17,932)
Fixed-rate property debt
Debt Instrument [Line Items]
Non-recourse property debt	3,676,882	3,480,378
Variable-rate property debt
Debt Instrument [Line Items]
Non-recourse property debt	$ 260,118	$ 82,663

Non-Recourse Property Debt an_4

Non-Recourse Property Debt and Credit Agreement - Non-Recourse Property Debt (Details) (Details) $ in Millions	Dec. 31, 2018USD ($)communityProperty
Debt Instrument [Line Items]
Number of apartment homes | community	6
Aimco Real Estate | Fixed Rate Property Debt
Debt Instrument [Line Items]
Weighted average interest rate	4.22%
Aggregate gross book value | $	$ 4,200
Aimco Real Estate | Fixed Rate Property Debt | Minimum
Debt Instrument [Line Items]
Interest rate	2.73%
Aimco Real Estate | Fixed Rate Property Debt | Maximum
Debt Instrument [Line Items]
Interest rate	7.14%
Aimco Real Estate | Fixed Rate Property Debt | Pledged as Collateral
Debt Instrument [Line Items]
Number of apartment homes | Property	82
Aimco Real Estate | Variable Rate Property Debt
Debt Instrument [Line Items]
Weighted average interest rate	3.61%
Aggregate gross book value | $	$ 239.5
Aimco Real Estate | Variable Rate Property Debt | Minimum
Debt Instrument [Line Items]
Interest rate	3.55%
Aimco Real Estate | Variable Rate Property Debt | Maximum
Debt Instrument [Line Items]
Interest rate	3.67%
Aimco Real Estate | Variable Rate Property Debt | Pledged as Collateral
Debt Instrument [Line Items]
Number of apartment homes | Property	8

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) - Aimco Real Estate $ in Thousands	Dec. 31, 2018USD ($)
Amortization
2,019	$ 77,791
2,020	79,592
2,021	69,995
2,022	64,991
2,023	55,450
Maturities
2,019	168,554
2,020	78,930
2,021	611,039
2,022	283,629
2,023	337,871
Thereafter	2,109,158
Total	3,937,000
Loans maturing in 2021 that may be prepaid without penalty	$ 246,500

Non-Recourse Property Debt an_6

Non-Recourse Property Debt and Credit Agreement - Credit Facility (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Credit facility interest rate at period end	3.93%	3.26%
Amount outstanding for undrawn letters of credit issued under revolving credit facility	$ 7,100,000
Remaining borrowing capacity under credit facility	632,500,000
Repayment of term loan	$ 250,000,000	$ (250,000,000)	$ 0
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 for such period, subject to certain non-cash adjustments, or such amount as may be necessary to maintain Aimco’s REIT status
London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Spread on variable interest rate	1.20%
Aimco Real Estate
Debt Instrument [Line Items]
Revolving loan commitments	$ 800,000,000
Outstanding borrowings under the revolving credit facility	160,360,000	$ 67,160,000
Aimco Real Estate | Term Loan
Debt Instrument [Line Items]
Repayment of term loan	$ 250,000,000

Commitments and Contingencies -

Commitments and Contingencies - Narrative (Details) $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2017party	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Commitments and Contingencies [Abstract]
Number of potentially-responsible parties | party	4
Ground Lease Obligations
Commitments and Contingencies [Abstract]
Rent expense		$ 2.3	$ 1.8	$ 1.7
Ground Lease Obligations | Minimum
Commitments and Contingencies [Abstract]
Lessee leasing arrangements, operating leases, term of contract		52 years
Ground Lease Obligations | Maximum
Commitments and Contingencies [Abstract]
Lessee leasing arrangements, operating leases, term of contract		99 years
Office Lease Obligations
Commitments and Contingencies [Abstract]
Rent expense		$ 2.8	$ 3	$ 3.3
Commitments related to development, redevelopment and capital improvement activities
Commitments and Contingencies [Abstract]
Commitments related to capital spending activities		$ 207
Long-term purchase commitment, period (or less)		12 months
Commitments related to operations | Maximum
Commitments and Contingencies [Abstract]
Long-term purchase commitment, period (or less)		1 year

Commitments and Contingencies_2

Commitments and Contingencies - Operating Leases (Details) $ in Thousands	Dec. 31, 2018USD ($)
Operating Leased Assets [Line Items]
2,019	$ 4,351
2,020	5,171
2,021	5,158
2,022	5,074
2,023	4,363
Thereafter	432,813
Total	456,930
Office Lease Obligations
Operating Leased Assets [Line Items]
2,019	2,237
2,020	2,821
2,021	2,719
2,022	2,582
2,023	1,871
Thereafter	10,644
Total	22,874
Ground Lease Obligations
Operating Leased Assets [Line Items]
2,019	2,114
2,020	2,350
2,021	2,439
2,022	2,492
2,023	2,492
Thereafter	422,169
Total	$ 434,056

Aimco Equity (Details)

Aimco Equity (Details) $ / shares in Units, $ in Thousands	Feb. 20, 2019	Feb. 03, 2019USD ($)shares	Jan. 31, 2019$ / shares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares
Classes of perpetual preferred stock
Preferred stock balance				$ 125,000	$ 125,000
Dividends declared per common share (in dollars per share) | $ / shares				$ 1.52	$ 1.44	$ 1.32
Cash dividends on common stock declared				$ 238,067	$ 226,172	$ 206,898
Subsequent Event
Classes of perpetual preferred stock
Cash dividends on common stock declared		$ 67,100
Stock dividends on common stock declared (in shares) | shares		4,500,000
Quarterly cash dividend amount (in dollars per share) | $ / shares			$ 0.39
Class A Cumulative Preferred Stock
Classes of perpetual preferred stock
Shares of preferred stock authorized (in shares) | shares				5,000,000	5,000,000	5,000,000
Shares of preferred stock issued (in shares) | shares				5,000,000	5,000,000	5,000,000
Shares of preferred stock outstanding (in shares) | shares				5,000,000	5,000,000	5,000,000
Preferred stock balance				$ 125,000	$ 125,000
Per share par value of preferred stock issued (in dollars per share) | $ / shares				$ 0.01
Preferred stock, liquidation preference per share (in dollars per share) | $ / shares				$ 25
Redemption date				May 17, 2019
Annual per share dividend rate (paid quarterly)				6.88%
Class Z Cumulative Preferred Stock
Classes of perpetual preferred stock
Preferred stock, redemption amount						$ 34,800
Preferred stock redemption premium						700
Previously deferred issuance costs reflected as an adjustment of net income attributable to preferred security holders						$ 1,300
Forecast
Classes of perpetual preferred stock
Reverse stock split, conversion ratio	0.9697534

Aimco Equity - Pro Forma Earnin

Aimco Equity - Pro Forma Earnings Per Share (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Equity [Abstract]
Weighted average shares, basic (in shares)	151,152	151,595	151,282
Weighted average shares, diluted (in shares)	151,334	152,060	151,669
Basic earnings per share (in dollars per share)	$ 4.34	$ 2.02	$ 2.76
Diluted earnings per share (in dollars per share)	$ 4.34	$ 2.02	$ 2.75

Partners' Capital - Classes of

Partners' Capital - Classes of Preferred OP Units (Details) - AIMCO PROPERTIES, L.P. - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Limited Partners' Capital Account [Line Items]
Units issued (in shares)	3,812,483	3,822,336
Units outstanding (in shares)	3,812,483	3,822,336
Redemption values	$ 101,291	$ 101,537
Class One
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
Limited Partners' Capital Account [Line Items]
Distributions per annum	1.92%
Distributions per annum (in dollars per share)	$ 0.48
Units issued (in shares)	14,240	17,750
Units outstanding (in shares)	14,240	17,750
Redemption values	$ 356	$ 444
Class Three
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	$ 33,462
Class Four
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
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	780,036
Units outstanding (in shares)	773,693	780,036
Redemption values	$ 19,342	$ 19,501
Class Seven
Limited Partners' Capital Account [Line Items]
Distributions per annum	7.87%
Distributions per annum (in dollars per share)	$ 1.97
Units issued (in shares)	27,960	27,960
Units outstanding (in shares)	27,960	27,960
Redemption values	$ 699	$ 699
Class Nine
Limited Partners' Capital Account [Line Items]
Distributions per annum	6.00%
Distributions per annum (in dollars per share)	$ 1.50
Units issued (in shares)	243,112	243,112
Units outstanding (in shares)	243,112	243,112
Redemption values	$ 6,078	$ 6,078
Class Ten
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) $ / shares in Units, shares in Thousands, $ in Thousands	Feb. 20, 2019	Feb. 03, 2019USD ($)shares	Dec. 31, 2018USD ($)$ / sharesshares	Dec. 31, 2017USD ($)$ / sharesshares	Dec. 31, 2016USD ($)$ / sharesshares
Related Party Transaction [Line Items]
Dividends declared per common share/unit (in dollars per share) | $ / shares			$ 1.52	$ 1.44	$ 1.32
Cash dividends on common stock declared | $			$ 238,067	$ 226,172	$ 206,898
Subsequent Event
Related Party Transaction [Line Items]
Cash dividends on common stock declared | $		$ 67,100
Stock dividends on common stock declared (in shares)		4,500
AIMCO PROPERTIES, L.P.
Related Party Transaction [Line Items]
Redeemable partnership preferred units redeemed for cash during period (in units)			10	67	69
Common OP Units redeemed in exchange for cash during period (in units)			224	268	248
Dividends declared per common share/unit (in dollars per share) | $ / shares			$ 1.52	$ 1.44	$ 1.32
AIMCO PROPERTIES, L.P. | Subsequent Event
Related Party Transaction [Line Items]
Cash dividends on common stock declared | $		$ 71,500
Stock dividends on common stock declared (in shares)		4,800
Forecast
Related Party Transaction [Line Items]
Reverse stock split, conversion ratio	0.9697534

Partners' Capital - Reconciliat

Partners' Capital - Reconciliation of Preferred OP Units (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance at January 1	$ 101,537
Balance at December 31	101,291	$ 101,537
AIMCO PROPERTIES, L.P.
Increase (Decrease) in Temporary Equity [Roll Forward]
Balance at January 1	101,537	103,201	$ 87,926
Preferred distributions	(7,740)	(7,764)	(7,239)
Redemption of preferred units and other	(246)	(1,664)	(1,725)
Issuance of preferred units	0	0	17,000
Net income	7,740	7,764	7,239
Balance at December 31	$ 101,291	$ 101,537	$ 103,201

Partners' Capital - Pro Forma E

Partners' Capital - Pro Forma Earnings per Common Unit (Details) - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Limited Partners' Capital Account [Line Items]
Weighted average units, basic (in shares)	151,152	151,595	151,282
Weighted average units, diluted (in shares)	151,334	152,060	151,669
Basic earnings per unit (in dollars per share)	$ 4.34	$ 2.02	$ 2.76
Diluted earnings per unit (in dollars per share)	$ 4.34	$ 2.02	$ 2.75
AIMCO PROPERTIES, L.P.
Limited Partners' Capital Account [Line Items]
Weighted average units, basic (in shares)	158,890	158,793	158,808
Weighted average units, diluted (in shares)	159,073	159,257	159,194
Basic earnings per unit (in dollars per share)	$ 4.35	$ 2.02	$ 2.76
Diluted earnings per unit (in dollars per share)	$ 4.34	$ 2.02	$ 2.75

Share-Based Compensation - Narr

Share-Based Compensation - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total compensation cost recognized for stock options and restricted stock awards	$ 9,700	$ 9,300	$ 8,600
Total compensation cost capitalized for options and restricted stock awards	1,200	1,400	1,000
Total unvested compensation cost not yet recognized for options and restricted stock awards	$ 11,000
Weighted average period over which unvested compensation cost expected to be recognized	1 year 7 months
Employee Stock Option
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
Options outstanding, aggregate intrinsic value	$ 2,500
Options outstanding, weighted average remaining contractual term	7 years
Options exercisable, aggregate intrinsic value	$ 1,100
Options exercisable, weighted average remaining contractual term	5 years 11 months
Intrinsic value of stock options exercised	$ 32	$ 7,100	$ 11,100
Options granted, weighted average grant-date fair value (dollars per share)		$ 11.39	$ 9.94
TSR Stock Awards
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
Restricted Stock
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vest period	4 years
Requisite service period	4 years
Aggregate fair value of shares that vested	$ 8,400	$ 6,000	$ 7,000
36 Months After Grant Date | TSR Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage, TSR restricted stock	50.00%
48 Months After Grant Date | TSR Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting percentage, TSR restricted stock	50.00%
NAREIT Apartment Index | TSR Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted percentage of index used to compare to TSR	60.00%
MSCI US REIT Index | TSR Stock Awards
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted percentage of index used to compare to TSR	40.00%
2015 Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available to be granted under plan (in shares)	4.7
Additional shares authorized under plan (in shares)	0.3

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Activity for Outstanding Stock Options (Details) - Employee Stock Option - $ / shares shares in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number of Options
Beginning balance (in shares)	648	675	1,394
Granted (in shares)	0	184	216
Exercised (in shares)	(2)	(211)	(934)
Forfeited (in shares)	0	0	(1)
Ending balance (in shares)	646	648	675
Exercisable at end of year (in shares)	186	128	280
Weighted Average Exercise Price, Stock Options
Beginning balance (in dollars per share)	$ 40.08	$ 29.55	$ 30.85
Granted (in dollars per share)	0	44.07	38.73
Exercised (in dollars per share)	28.33	9.90	33.61
Forfeited (in dollars per share)	0	0	29.11
Ending balance (in dollars per share)	40.12	40.08	29.55
Exercisable (in dollars per share)	$ 38.18	$ 37.59	$ 16.38

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Time-Based Restricted Stock Awards
Number of Shares
Unvested (in shares)	160	249	339
Granted (in shares)	51	45	91
Vested (in shares)	(86)	(134)	(181)
Unvested (in shares)	125	160	249
Weighted Average Grant-Date Fair Value
Unvested (in dollars per share)	$ 37.63	$ 33.61	$ 29.96
Granted (in dollars per share)	40.01	44.07	40.03
Vested (in dollars per share)	34.42	32.35	29.99
Unvested (in dollars per share)	$ 40.82	$ 37.63	$ 33.61
TSR Restricted Stock Awards
Number of Shares
Unvested (in shares)	253	214	123
Granted (in shares)	45	39	91
Vested (in shares)	(123)	0	0
Unvested (in shares)	175	253	214
Weighted Average Grant-Date Fair Value
Unvested (in dollars per share)	$ 40.70	$ 39.66	$ 39.72
Granted (in dollars per share)	41.71	46.39	39.59
Vested (in dollars per share)	39.72	0	0
Unvested (in dollars per share)	$ 41.65	$ 40.70	$ 39.66
TSR LTIP I Units
Number of Shares
Unvested (in shares)	45	0
Granted (in shares)	48	45
Unvested (in shares)	93	45	0
Weighted Average Grant-Date Fair Value
Unvested (in dollars per share)	$ 46.21	$ 0
Granted (in dollars per share)	41.48	46.21
Unvested (in dollars per share)	$ 43.78	$ 46.21	$ 0
TSR LTIP II Units
Number of Shares
Unvested (in shares)	0
Granted (in shares)	243
Unvested (in shares)	243	0
Weighted Average Grant-Date Fair Value
Unvested (in dollars per share)	$ 0
Granted (in dollars per share)	41.84
Unvested (in dollars per share)	$ 41.84	$ 0

Share-Based Compensation - Assu

Share-Based Compensation - Assumptions Used in the Determination of Grant-Date Fair Value of Awards (Details) - TSR Stock Awards - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Grant date market value of a common share (dollars per share)	$ 40.95	$ 44.07	$ 38.73
Risk-free interest rate	2.32%	1.57%	1.15%
Expected dividend yield	3.52%	3.27%	3.41%
Expected volatility	18.02%	21.33%	21.24%
Derived vesting period of TSR Restricted Stock and TSR LTIP I units	3 years 5 months	3 years 5 months	3 years 5 months
Weighted average expected term of options	5 years 7 months	5 years 9 months	5 years 9 months

Income Taxes - Components of De

Income Taxes - Components of Deferred Tax Liabilities and Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax liabilities:
Real estate and real estate partnership basis differences	$ 12,058	$ 32,032
Deferred tax assets:
Net operating, capital and other loss carryforwards	7,022	9,523
Accruals and expenses	7,432	6,575
Tax credit carryforwards	67,530	73,450
Management contracts and other	2,064	200
Total deferred tax assets	84,048	89,748
Valuation allowance	(4,930)	(25,489)
Net deferred tax assets	$ 67,060	$ 32,227

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended			24 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Income Taxes (Textual) [Abstract]
Net tax benefit due to the tax effects of the 2017 Act				$ 15,600
Operating loss carryforwards	$ 7,000			7,000
Valuation allowance	4,900			4,900
Net deferred tax asset related to tax credit carryforwards	67,500			67,500
Valuation allowance	4,930	$ 25,489		4,930
Consolidated income (loss) subject to tax	158,600	(55,600)	$ 109,300
Cash paid for income taxes	11,522	7,401	$ 2,152
Low-Income Housing and Rehabilitation Tax Credit Carryforward
Income Taxes (Textual) [Abstract]
Valuation allowance	$ 15,400	$ 15,400		$ 15,400
Minimum
Income Taxes (Textual) [Abstract]
Expiration years of net operating loss carryforwards	Dec. 31, 2019
Tax credit carryforward, expiration date	Dec. 31, 2034
Maximum
Income Taxes (Textual) [Abstract]
Expiration years of net operating loss carryforwards	Dec. 31, 2034
Tax credit carryforward, expiration date	Dec. 31, 2038

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of unrecognized tax benefits
Balance at January 1	$ 2,476	$ 2,286	$ 2,897
Additions (reductions) based on tax positions related to prior years	142	190	(611)
Balance at December 31	$ 2,618	$ 2,476	$ 2,286

Income Taxes - Components of In

Income Taxes - Components of Income Tax Benefit or Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ 11,269	$ (938)	$ 5,038
State	10,537	525	2,916
Total current	21,806	(413)	7,954
Deferred:
Federal	(29,243)	(10,908)	(26,173)
State	(5,590)	(3,621)	(623)
Revaluation of deferred taxes due to change in tax rate	0	(15,894)	0
Total deferred	(34,833)	(30,423)	(26,796)
Total income tax benefit	$ (13,027)	$ (30,836)	$ (18,842)

Income Taxes - Reconciliation_2

Income Taxes - Reconciliation of Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amount
Tax provision (benefit) at United States statutory rates on consolidated income or loss subject to tax	$ 33,296	$ (19,459)	$ 38,257
State income tax expense, net of federal tax (benefit) expense	12,252	(1,769)	7,152
Establishment of deferred tax asset related to partnership basis difference	0	(3,501)	0
Effect of permanent differences	302	(1,629)	(132)
Tax effect of intercompany transactions	(33,250)	0	(47,369)
Tax credits	(6,897)	(9,607)	(16,750)
Tax reform revaluation	288	(15,894)	0
Increase in valuation allowance	(20,434)	21,023	0
Other	1,416	0	0
Total income tax benefit	$ (13,027)	$ (30,836)	$ (18,842)
Percent
Tax provision (benefit) at United States statutory rates on consolidated income or loss subject to tax	21.00%	35.00%	35.00%
State income tax expense, net of federal tax (benefit) expense	7.70%	3.20%	6.50%
Establishment of deferred tax asset related to partnership basis difference	0.00%	6.30%	0.00%
Effect of permanent differences	0.20%	2.90%	(0.10%)
Tax effect of intercompany transactions	(21.00%)	(0.00%)	(43.30%)
Tax credits	(4.40%)	17.30%	(15.30%)
Tax reform revaluation	0.002	0.286	0
Increase in valuation allowance	(12.90%)	(37.80%)	0.00%
Other	0.90%	0.00%	0.00%
Total income tax benefit	(8.30%)	55.50%	(17.20%)
Tax Credit Carryforward [Line Items]
Valuation allowance against the deferred tax assets associated with rehabilitation tax credits due to lower federal tax rate under the 2017 Act	$ 4,930	$ 25,489
Low-Income Housing and Rehabilitation Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Valuation allowance against the deferred tax assets associated with rehabilitation tax credits due to lower federal tax rate under the 2017 Act	$ 15,400	$ 15,400

Income Taxes - Schedule of Divi

Income Taxes - Schedule of Dividends Per Share Held (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amount
Ordinary income (dollars per share)	$ 0.51	$ 0.75	$ 0.45
Capital gains (dollars per share)	0.93	0.51	0.47
Qualified dividends (dollars per share)	0	0.02	0.13
Unrecaptured Section 1250 gain (dollars per share)	0.08	0.16	0.27
Total (dollars per share)	$ 1.52	$ 1.44	$ 1.32
Percentage
Ordinary income	33.40%	51.50%	34.20%
Capital gains	61.20%	35.70%	35.40%
Qualified dividends	0.00%	1.60%	9.90%
Unrecaptured Section 1250 gain	5.40%	11.20%	20.50%
Total	100.00%	100.00%	100.00%

Earnings per Share_Unit (Detail

Earnings per Share/Unit (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive effect of securities (in shares)	0.2	0.5	0.4
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.3	0.2
Participating securities outstanding (in shares)	0.3	0.2	0.2
Number of shares of common stock required to redeem preferred OP units tendered for redemption, if parent chooses to redeem in shares rather than cash (in shares)	2.3
AIMCO Properties, L.P.
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Dilutive effect of securities (in shares)			0.4
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0.3	0.2
Participating securities outstanding (in shares)	0.6	0.3	0.2

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Expected Term
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Expected remaining term of available for sale securities	2 years 5 months
Available-for-sale Securities
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Face amount of investment in available-for-sale debt securities	$ 100.9
Amortized cost of the investment in available-for-sale debt securities	83.6	$ 77.7
Available-for-sale Securities | Fair Value, Inputs, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage-backed securities available-for-sale, fair value disclosure	$ 88.5	$ 82.8

Business Segments - Narrative (

Business Segments - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018USD ($)communityPropertyapartment_homeSegment	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Segment Reporting Information [Line Items]
Number of apartment homes | community	6
Number of apartment communities	1,480
Number of reportable segments | Segment	1
Real Estate | Aimco Real Estate
Segment Reporting Information [Line Items]
Capital additions related to segments | $	$ 338.8	$ 321.9	$ 312.8
Wholly and Partially Owned and Consolidated Properties | Aimco Real Estate
Segment Reporting Information [Line Items]
Number of apartment homes | Property	130
Number of apartment communities	36,407
Unconsolidated Properties | Aimco Real Estate
Segment Reporting Information [Line Items]
Number of apartment homes | Property	4
Number of apartment communities	142

Business Segments - Revenues, N

Business Segments - Revenues, Net Operating Income and Income Before Gain on Dispositions of Real Estate Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary information for the reportable segments
Tax credit and transaction revenues									$ 6,987	$ 13,243	$ 21,323
Total revenues	$ 232,022	$ 242,481	$ 250,187	$ 247,720	$ 255,229	$ 254,635	$ 249,092	$ 246,481	972,410	1,005,437	995,854
Other operating expenses not allocated to reportable segment									427,832	456,870	394,145
Total operating expenses									756,654	811,454	749,058
Proportionate property net operating income									0	0	0
Other items included in income before income tax benefit									487,820	122,260	217,635
Income before income tax benefit									703,576	316,243	464,431
Asset Management
Summary information for the reportable segments
Rental and other property revenues									42,830	74,046	74,640
Property operating expenses									20,921	35,458	36,956
Aimco Real Estate
Summary information for the reportable segments
Rental and other property revenues									922,593	918,148	899,891
Property operating expenses									307,901	319,126	317,957
Real Estate | Aimco Real Estate
Summary information for the reportable segments
Rental and other property revenues									854,240	781,194	720,302
Total revenues									854,240	781,194	720,302
Property operating expenses									238,860	222,731	210,426
Total operating expenses									238,860	222,731	210,426
Proportionate property net operating income									615,380	558,463	509,876
Income before income tax benefit									615,380	558,463	509,876
Real Estate | Aimco Real Estate | Asset Management
Summary information for the reportable segments
Rental and other property revenues									0	0	0
Property operating expenses									0	0	0
Proportionate and Other Adjustments
Summary information for the reportable segments
Total revenues									34,282	43,043	55,257
Total operating expenses									32,169	32,432	35,468
Proportionate property net operating income									0	0	0
Income before income tax benefit									2,113	10,611	19,789
Proportionate and Other Adjustments | Aimco Real Estate
Summary information for the reportable segments
Rental and other property revenues									34,282	43,043	55,257
Property operating expenses									32,169	32,432	35,468
Corporate and Amounts Not Allocated to Reportable Segment
Summary information for the reportable segments
Tax credit and transaction revenues									6,987	13,243	21,323
Total revenues									83,888	181,200	220,295
Other operating expenses not allocated to reportable segment									427,832	456,870	394,145
Total operating expenses									485,625	556,291	503,164
Proportionate property net operating income									0	0	0
Other items included in income before income tax benefit									487,820	122,260	217,635
Income before income tax benefit									86,083	(252,831)	(65,234)
Corporate and Amounts Not Allocated to Reportable Segment | Asset Management
Summary information for the reportable segments
Rental and other property revenues									42,830	74,046	74,640
Property operating expenses									20,921	35,458	36,956
Corporate and Amounts Not Allocated to Reportable Segment | Aimco Real Estate
Summary information for the reportable segments
Rental and other property revenues									34,071	93,911	124,332
Property operating expenses									$ 36,872	$ 63,963	$ 72,063

Business Segments - Assets of R

Business Segments - Assets of Reportable Segments and Consolidated Assets Not Allocated to Segments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total assets	$ 6,190,004	$ 6,079,040
Real Estate | Aimco Real Estate
Segment Reporting Information [Line Items]
Total assets	5,849,638	5,346,390
Corporate and other assets
Segment Reporting Information [Line Items]
Total assets	$ 340,366	$ 732,650

Variable Interest Entities - Su

Variable Interest Entities - Summary of Consolidated VIEs (Details)	Dec. 31, 2018communityPropertyapartment_homeEntity	Dec. 31, 2017Propertyapartment_homeEntity
Variable Interest Entity [Line Items]
Apartment communities owned by VIEs | community	6
Apartment homes in communities owned by VIEs	1,480
Real Estate Portfolio | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
VIEs with interests in apartment communities | Entity	9	14
Apartment communities owned by VIEs | Property	9	14
Apartment homes in communities owned by VIEs	3,592	4,321
Consolidated Partnerships Served by the Asset Management Business | Variable Interest Entity, Primary Beneficiary
Variable Interest Entity [Line Items]
VIEs with interests in apartment communities | Entity	0	49
Apartment communities owned by VIEs | Property	0	37
Apartment homes in communities owned by VIEs	0	5,893

Variable Interest Entities - _2

Variable Interest Entities - Summary of Assets and Liabilities of VIEs (Details) - Variable Interest Entity, Primary Beneficiary - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Aimco Real Estate
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Net real estate	$ 488,127	$ 529,898
Cash and cash equivalents	15,416	16,111
Restricted cash	4,461	4,798
Non-recourse property debt	322,685	412,205
Accrued liabilities and other	13,576	10,623
Held-for-sale, Not Discontinued Operations | Asset Management
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Net real estate	0	215,580
Cash and cash equivalents	0	15,931
Restricted cash	0	30,107
Non-recourse property debt	0	220,356
Accrued liabilities and other	$ 0	$ 20,241

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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summarized unaudited consolidated quarterly information
Total revenues	$ 232,022	$ 242,481	$ 250,187	$ 247,720	$ 255,229	$ 254,635	$ 249,092	$ 246,481	$ 972,410	$ 1,005,437	$ 995,854
Net income	9,840	603,917	7,156	95,690	286,189	22,144	21,591	17,155	716,603	347,079	483,273
Net income attributable to Aimco common stockholders	$ 5,226	$ 567,029	$ 2,817	$ 81,525	$ 262,097	$ 17,430	$ 15,843	$ 11,491	$ 656,597	$ 306,861	$ 417,781
Net income attributable to the company per common share/unit - basic (in dollars per share)	$ 0.03	$ 3.62	$ 0.02	$ 0.52	$ 1.68	$ 0.11	$ 0.10	$ 0.07	$ 4.21	$ 1.96	$ 2.68
Net income attributable to the company per common share/unit - diluted (in dollars per share)	$ 0.03	$ 3.61	$ 0.02	$ 0.52	$ 1.67	$ 0.11	$ 0.10	$ 0.07	$ 4.21	$ 1.96	$ 2.67
AIMCO PROPERTIES, L.P.
Summarized unaudited consolidated quarterly information
Total revenues	$ 232,022	$ 242,481	$ 250,187	$ 247,720	$ 255,229	$ 254,635	$ 249,092	$ 246,481
Net income	9,840	603,917	7,156	95,690	286,189	22,144	21,591	17,155
Net income attributable to Aimco common stockholders	$ 5,551	$ 597,100	$ 2,949	$ 85,274	$ 274,380	$ 18,246	$ 16,627	$ 12,047
Net income attributable to the company per common share/unit - basic (in dollars per share)	$ 0.03	$ 3.62	$ 0.02	$ 0.52	$ 1.68	$ 0.11	$ 0.10	$ 0.07
Net income attributable to the company per common share/unit - diluted (in dollars per share)	$ 0.03	$ 3.61	$ 0.02	$ 0.52	$ 1.67	$ 0.11	$ 0.10	$ 0.07

Real Estate and Accumulated D_2

Real Estate and Accumulated Depreciation - Schedule of Real Estate and Accumulated Depreciation (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)apartment_home	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment communities | apartment_home	1,480
Real Estate and Accumulated Depreciation (Textual) [Abstract]
Aggregate cost of land and depreciable property for federal income tax purposes	$ 4,000,000
Aimco Real Estate
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Total	8,308,590	$ 7,927,753	$ 7,931,117	$ 7,744,894
Accumulated Depreciation (AD)	$ (2,585,115)	$ (2,522,358)	$ (2,421,357)	$ (2,488,448)
Aimco Real Estate | Real Estate Segment: | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment communities | apartment_home	35,625
Initial Cost, Land	$ 1,846,000
Initial Cost, Buildings and Improvements	3,494,014
Costs Capitalized Subsequent to Consolidation	3,058,051
Land	1,756,525
Buildings and Improvements	6,552,065
Total	8,308,590
Accumulated Depreciation (AD)	(2,585,115)
Total Cost Net of Accumulated Depreciation	5,723,475
Encumbrances	$ 3,937,000
Aimco Real Estate | 100 Forest Place | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 1, 1997
Location	Oak Park, IL
Number of apartment communities | apartment_home	234
Initial Cost, Land	$ 2,664
Initial Cost, Buildings and Improvements	18,815
Costs Capitalized Subsequent to Consolidation	10,553
Land	2,664
Buildings and Improvements	29,368
Total	32,032
Accumulated Depreciation (AD)	(15,640)
Total Cost Net of Accumulated Depreciation	16,392
Encumbrances	$ 35,048
Aimco Real Estate | 118-122 West 23rd Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jun. 1, 2012
Location	New York, NY
Number of apartment communities | apartment_home	42
Initial Cost, Land	$ 14,985
Initial Cost, Buildings and Improvements	23,459
Costs Capitalized Subsequent to Consolidation	6,752
Land	14,985
Buildings and Improvements	30,211
Total	45,196
Accumulated Depreciation (AD)	(9,121)
Total Cost Net of Accumulated Depreciation	36,075
Encumbrances	$ 17,457
Aimco Real Estate | 173 E. 90th Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	May 4, 2004
Location	New York, NY
Number of apartment communities | apartment_home	72
Initial Cost, Land	$ 12,066
Initial Cost, Buildings and Improvements	4,535
Costs Capitalized Subsequent to Consolidation	8,068
Land	12,066
Buildings and Improvements	12,603
Total	24,669
Accumulated Depreciation (AD)	(3,730)
Total Cost Net of Accumulated Depreciation	20,939
Encumbrances	$ 0
Aimco Real Estate | 182-188 Columbus Avenue | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Feb. 1, 2007
Location	New York, NY
Number of apartment communities | apartment_home	32
Initial Cost, Land	$ 19,123
Initial Cost, Buildings and Improvements	3,300
Costs Capitalized Subsequent to Consolidation	5,513
Land	19,123
Buildings and Improvements	8,813
Total	27,936
Accumulated Depreciation (AD)	(3,968)
Total Cost Net of Accumulated Depreciation	23,968
Encumbrances	$ 13,925
Aimco Real Estate | 1045 on the Park Apartments Homes | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Jul. 1, 2013
Location	Atlanta, GA
Number of apartment communities | apartment_home	30
Initial Cost, Land	$ 2,793
Initial Cost, Buildings and Improvements	6,662
Costs Capitalized Subsequent to Consolidation	692
Land	2,793
Buildings and Improvements	7,354
Total	10,147
Accumulated Depreciation (AD)	(1,423)
Total Cost Net of Accumulated Depreciation	8,724
Encumbrances	$ 5,627
Aimco Real Estate | 1582 First Avenue | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 1, 2005
Location	New York, NY
Number of apartment communities | apartment_home	17
Initial Cost, Land	$ 4,281
Initial Cost, Buildings and Improvements	752
Costs Capitalized Subsequent to Consolidation	499
Land	4,281
Buildings and Improvements	1,251
Total	5,532
Accumulated Depreciation (AD)	(578)
Total Cost Net of Accumulated Depreciation	4,954
Encumbrances	$ 2,273
Aimco Real Estate | 21 Fitzsimons | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Aug. 1, 2014
Location	Aurora, CO
Number of apartment communities | apartment_home	600
Initial Cost, Land	$ 12,864
Initial Cost, Buildings and Improvements	104,720
Costs Capitalized Subsequent to Consolidation	20,379
Land	12,864
Buildings and Improvements	125,099
Total	137,963
Accumulated Depreciation (AD)	(19,590)
Total Cost Net of Accumulated Depreciation	118,373
Encumbrances	$ 90,000
Aimco Real Estate | 2200 Grace | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Aug. 1, 2018
Location	Lombard, IL
Number of apartment communities | apartment_home	72
Initial Cost, Land	$ 642
Initial Cost, Buildings and Improvements	7,788
Costs Capitalized Subsequent to Consolidation	90
Land	642
Buildings and Improvements	7,878
Total	8,520
Accumulated Depreciation (AD)	(4,014)
Total Cost Net of Accumulated Depreciation	4,506
Encumbrances	$ 0
Aimco Real Estate | 234 East 88th Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Jan. 1, 2014
Location	New York, NY
Number of apartment communities | apartment_home	20
Initial Cost, Land	$ 2,448
Initial Cost, Buildings and Improvements	4,449
Costs Capitalized Subsequent to Consolidation	807
Land	2,448
Buildings and Improvements	5,256
Total	7,704
Accumulated Depreciation (AD)	(1,154)
Total Cost Net of Accumulated Depreciation	6,550
Encumbrances	$ 3,223
Aimco Real Estate | 236-238 East 88th Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 4, 2004
Location	New York, NY
Number of apartment communities | apartment_home	43
Initial Cost, Land	$ 8,820
Initial Cost, Buildings and Improvements	2,914
Costs Capitalized Subsequent to Consolidation	2,681
Land	8,820
Buildings and Improvements	5,595
Total	14,415
Accumulated Depreciation (AD)	(1,930)
Total Cost Net of Accumulated Depreciation	12,485
Encumbrances	$ 10,875
Aimco Real Estate | 237-239 Ninth Avenue | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 1, 2005
Location	New York, NY
Number of apartment communities | apartment_home	36
Initial Cost, Land	$ 8,495
Initial Cost, Buildings and Improvements	1,866
Costs Capitalized Subsequent to Consolidation	3,092
Land	8,495
Buildings and Improvements	4,958
Total	13,453
Accumulated Depreciation (AD)	(2,770)
Total Cost Net of Accumulated Depreciation	10,683
Encumbrances	$ 5,553
Aimco Real Estate | 240 West 73rd Street, LLC | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 1, 2004
Location	New York, NY
Number of apartment communities | apartment_home	200
Initial Cost, Land	$ 68,109
Initial Cost, Buildings and Improvements	12,140
Costs Capitalized Subsequent to Consolidation	11,905
Land	68,109
Buildings and Improvements	24,045
Total	92,154
Accumulated Depreciation (AD)	(9,818)
Total Cost Net of Accumulated Depreciation	82,336
Encumbrances	$ 0
Aimco Real Estate | 2900 on First Apartments | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Oct. 1, 2008
Location	Seattle, WA
Number of apartment communities | apartment_home	135
Initial Cost, Land	$ 19,070
Initial Cost, Buildings and Improvements	17,518
Costs Capitalized Subsequent to Consolidation	33,542
Land	19,070
Buildings and Improvements	51,060
Total	70,130
Accumulated Depreciation (AD)	(25,554)
Total Cost Net of Accumulated Depreciation	44,576
Encumbrances	$ 13,915
Aimco Real Estate | 306 East 89th Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jul. 4, 2004
Location	New York, NY
Number of apartment communities | apartment_home	20
Initial Cost, Land	$ 2,680
Initial Cost, Buildings and Improvements	1,006
Costs Capitalized Subsequent to Consolidation	1,098
Land	2,680
Buildings and Improvements	2,104
Total	4,784
Accumulated Depreciation (AD)	(888)
Total Cost Net of Accumulated Depreciation	3,896
Encumbrances	$ 1,854
Aimco Real Estate | 311 & 313 East 73rd Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Mar. 1, 2003
Location	New York, NY
Number of apartment communities | apartment_home	34
Initial Cost, Land	$ 5,678
Initial Cost, Buildings and Improvements	1,609
Costs Capitalized Subsequent to Consolidation	520
Land	5,678
Buildings and Improvements	2,129
Total	7,807
Accumulated Depreciation (AD)	(1,487)
Total Cost Net of Accumulated Depreciation	6,320
Encumbrances	$ 3,904
Aimco Real Estate | 322-324 East 61st Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 1, 2005
Location	New York, NY
Number of apartment communities | apartment_home	40
Initial Cost, Land	$ 6,372
Initial Cost, Buildings and Improvements	2,224
Costs Capitalized Subsequent to Consolidation	1,512
Land	6,372
Buildings and Improvements	3,736
Total	10,108
Accumulated Depreciation (AD)	(1,830)
Total Cost Net of Accumulated Depreciation	8,278
Encumbrances	$ 3,410
Aimco Real Estate | 3400 Avenue of the Arts | Continuing Operations
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
Number of apartment communities | apartment_home	770
Initial Cost, Land	$ 57,241
Initial Cost, Buildings and Improvements	65,506
Costs Capitalized Subsequent to Consolidation	80,349
Land	57,241
Buildings and Improvements	145,855
Total	203,096
Accumulated Depreciation (AD)	(86,923)
Total Cost Net of Accumulated Depreciation	116,173
Encumbrances	$ 145,752
Aimco Real Estate | 452 East 78th Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 4, 2004
Location	New York, NY
Number of apartment communities | apartment_home	12
Initial Cost, Land	$ 1,982
Initial Cost, Buildings and Improvements	608
Costs Capitalized Subsequent to Consolidation	548
Land	1,982
Buildings and Improvements	1,156
Total	3,138
Accumulated Depreciation (AD)	(486)
Total Cost Net of Accumulated Depreciation	2,652
Encumbrances	$ 2,542
Aimco Real Estate | 464-466 Amsterdam & 200-210 W. 83rd Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Feb. 1, 2007
Location	New York, NY
Number of apartment communities | apartment_home	71
Initial Cost, Land	$ 25,553
Initial Cost, Buildings and Improvements	7,101
Costs Capitalized Subsequent to Consolidation	6,070
Land	25,553
Buildings and Improvements	13,171
Total	38,724
Accumulated Depreciation (AD)	(6,031)
Total Cost Net of Accumulated Depreciation	32,693
Encumbrances	$ 20,520
Aimco Real Estate | 510 East 88th Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 4, 2004
Location	New York, NY
Number of apartment communities | apartment_home	20
Initial Cost, Land	$ 3,163
Initial Cost, Buildings and Improvements	1,002
Costs Capitalized Subsequent to Consolidation	622
Land	3,163
Buildings and Improvements	1,624
Total	4,787
Accumulated Depreciation (AD)	(642)
Total Cost Net of Accumulated Depreciation	4,145
Encumbrances	$ 2,724
Aimco Real Estate | 514-516 East 88th Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 1, 2005
Location	New York, NY
Number of apartment communities | apartment_home	36
Initial Cost, Land	$ 6,282
Initial Cost, Buildings and Improvements	2,168
Costs Capitalized Subsequent to Consolidation	1,593
Land	6,282
Buildings and Improvements	3,761
Total	10,043
Accumulated Depreciation (AD)	(1,619)
Total Cost Net of Accumulated Depreciation	8,424
Encumbrances	$ 3,696
Aimco Real Estate | 518 East 88th Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Jan. 1, 2014
Location	New York, NY
Number of apartment communities | apartment_home	20
Initial Cost, Land	$ 2,233
Initial Cost, Buildings and Improvements	4,315
Costs Capitalized Subsequent to Consolidation	606
Land	2,233
Buildings and Improvements	4,921
Total	7,154
Accumulated Depreciation (AD)	(1,137)
Total Cost Net of Accumulated Depreciation	6,017
Encumbrances	$ 2,792
Aimco Real Estate | 707 Leahy | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Apr. 1, 2007
Location	Redwood City, CA
Number of apartment communities | apartment_home	110
Initial Cost, Land	$ 15,444
Initial Cost, Buildings and Improvements	7,909
Costs Capitalized Subsequent to Consolidation	7,406
Land	15,444
Buildings and Improvements	15,315
Total	30,759
Accumulated Depreciation (AD)	(6,964)
Total Cost Net of Accumulated Depreciation	23,795
Encumbrances	$ 8,737
Aimco Real Estate | 777 South Broad Street | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	May 1, 2018
Location	Philadelphia, PA
Number of apartment communities | apartment_home	146
Initial Cost, Land	$ 6,986
Initial Cost, Buildings and Improvements	67,512
Costs Capitalized Subsequent to Consolidation	829
Land	6,986
Buildings and Improvements	68,341
Total	75,327
Accumulated Depreciation (AD)	(1,515)
Total Cost Net of Accumulated Depreciation	73,812
Encumbrances	$ 57,627
Aimco Real Estate | 865 Bellevue | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 1, 2000
Location	Nashville, TN
Number of apartment communities | apartment_home	326
Initial Cost, Land	$ 3,562
Initial Cost, Buildings and Improvements	12,037
Costs Capitalized Subsequent to Consolidation	23,538
Land	3,562
Buildings and Improvements	35,575
Total	39,137
Accumulated Depreciation (AD)	(23,393)
Total Cost Net of Accumulated Depreciation	15,744
Encumbrances	$ 0
Aimco Real Estate | Avery Row | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 1, 2018
Location	Arlington, VA
Number of apartment communities | apartment_home	67
Initial Cost, Land	$ 8,140
Initial Cost, Buildings and Improvements	21,348
Costs Capitalized Subsequent to Consolidation	0
Land	8,140
Buildings and Improvements	21,348
Total	29,488
Accumulated Depreciation (AD)	0
Total Cost Net of Accumulated Depreciation	29,488
Encumbrances	$ 0
Aimco Real Estate | Axiom | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Apr. 15, 2015
Location	Cambridge, MA
Number of apartment communities | apartment_home	115
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	63,612
Costs Capitalized Subsequent to Consolidation	2,444
Land	0
Buildings and Improvements	66,056
Total	66,056
Accumulated Depreciation (AD)	(8,920)
Total Cost Net of Accumulated Depreciation	57,136
Encumbrances	$ 32,978
Aimco Real Estate | Bank Lofts | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Apr. 1, 2001
Location	Denver, CO
Number of apartment communities | apartment_home	125
Initial Cost, Land	$ 3,525
Initial Cost, Buildings and Improvements	9,045
Costs Capitalized Subsequent to Consolidation	5,539
Land	3,525
Buildings and Improvements	14,584
Total	18,109
Accumulated Depreciation (AD)	(7,463)
Total Cost Net of Accumulated Depreciation	10,646
Encumbrances	$ 10,476
Aimco Real Estate | Bay Parc Plaza | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 1, 2004
Location	Miami, FL
Number of apartment communities | apartment_home	474
Initial Cost, Land	$ 22,680
Initial Cost, Buildings and Improvements	41,847
Costs Capitalized Subsequent to Consolidation	34,053
Land	22,680
Buildings and Improvements	75,900
Total	98,580
Accumulated Depreciation (AD)	(22,485)
Total Cost Net of Accumulated Depreciation	76,095
Encumbrances	$ 42,434
Aimco Real Estate | Bay Ridge at Nashua | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 3, 2003
Location	Nashua, NH
Number of apartment communities | apartment_home	412
Initial Cost, Land	$ 3,262
Initial Cost, Buildings and Improvements	40,713
Costs Capitalized Subsequent to Consolidation	16,739
Land	3,262
Buildings and Improvements	57,452
Total	60,714
Accumulated Depreciation (AD)	(22,738)
Total Cost Net of Accumulated Depreciation	37,976
Encumbrances	$ 51,450
Aimco Real Estate | Bayberry Hill Estates | Continuing Operations
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
Number of apartment communities | apartment_home	424
Initial Cost, Land	$ 19,944
Initial Cost, Buildings and Improvements	35,945
Costs Capitalized Subsequent to Consolidation	21,847
Land	19,944
Buildings and Improvements	57,792
Total	77,736
Accumulated Depreciation (AD)	(27,629)
Total Cost Net of Accumulated Depreciation	50,107
Encumbrances	$ 0
Aimco Real Estate | Bent Tree Apartments | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Feb. 1, 2018
Location	Centreville, VA
Number of apartment communities | apartment_home	748
Initial Cost, Land	$ 46,975
Initial Cost, Buildings and Improvements	113,695
Costs Capitalized Subsequent to Consolidation	7,493
Land	46,975
Buildings and Improvements	121,188
Total	168,163
Accumulated Depreciation (AD)	(4,331)
Total Cost Net of Accumulated Depreciation	163,832
Encumbrances	$ 0
Aimco Real Estate | Bluffs at Pacifica, The | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 6, 2006
Location	Pacifica, CA
Number of apartment communities | apartment_home	64
Initial Cost, Land	$ 8,108
Initial Cost, Buildings and Improvements	4,132
Costs Capitalized Subsequent to Consolidation	17,804
Land	8,108
Buildings and Improvements	21,936
Total	30,044
Accumulated Depreciation (AD)	(10,996)
Total Cost Net of Accumulated Depreciation	19,048
Encumbrances	$ 0
Aimco Real Estate | Boston Lofts | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Apr. 1, 2001
Location	Denver, CO
Number of apartment communities | apartment_home	158
Initial Cost, Land	$ 3,446
Initial Cost, Buildings and Improvements	20,589
Costs Capitalized Subsequent to Consolidation	5,694
Land	3,446
Buildings and Improvements	26,283
Total	29,729
Accumulated Depreciation (AD)	(13,914)
Total Cost Net of Accumulated Depreciation	15,815
Encumbrances	$ 15,303
Aimco Real Estate | Boulder Creek | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 1, 1994
Location	Boulder, CO
Number of apartment communities | apartment_home	221
Initial Cost, Land	$ 754
Initial Cost, Buildings and Improvements	7,730
Costs Capitalized Subsequent to Consolidation	20,628
Land	754
Buildings and Improvements	28,358
Total	29,112
Accumulated Depreciation (AD)	(19,702)
Total Cost Net of Accumulated Depreciation	9,410
Encumbrances	$ 38,500
Aimco Real Estate | Broadcast Center | Continuing Operations
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
Number of apartment communities | apartment_home	279
Initial Cost, Land	$ 29,407
Initial Cost, Buildings and Improvements	41,244
Costs Capitalized Subsequent to Consolidation	28,683
Land	29,407
Buildings and Improvements	69,927
Total	99,334
Accumulated Depreciation (AD)	(29,655)
Total Cost Net of Accumulated Depreciation	69,679
Encumbrances	$ 0
Aimco Real Estate | Broadway Lofts | Continuing Operations
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
Number of apartment communities | apartment_home	84
Initial Cost, Land	$ 5,367
Initial Cost, Buildings and Improvements	14,442
Costs Capitalized Subsequent to Consolidation	6,126
Land	5,367
Buildings and Improvements	20,568
Total	25,935
Accumulated Depreciation (AD)	(4,604)
Total Cost Net of Accumulated Depreciation	21,331
Encumbrances	$ 11,531
Aimco Real Estate | Burke Shire Commons | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Mar. 1, 2001
Location	Burke, VA
Number of apartment communities | apartment_home	360
Initial Cost, Land	$ 4,867
Initial Cost, Buildings and Improvements	23,617
Costs Capitalized Subsequent to Consolidation	17,678
Land	4,867
Buildings and Improvements	41,295
Total	46,162
Accumulated Depreciation (AD)	(24,737)
Total Cost Net of Accumulated Depreciation	21,425
Encumbrances	$ 57,860
Aimco Real Estate | Calhoun Beach Club | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 30, 1998
Location	Minneapolis, MN
Number of apartment communities | apartment_home	332
Initial Cost, Land	$ 11,708
Initial Cost, Buildings and Improvements	73,334
Costs Capitalized Subsequent to Consolidation	64,948
Land	11,708
Buildings and Improvements	138,282
Total	149,990
Accumulated Depreciation (AD)	(79,547)
Total Cost Net of Accumulated Depreciation	70,443
Encumbrances	$ 0
Aimco Real Estate | Canyon Terrace | Continuing Operations
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
Number of apartment communities | apartment_home	130
Initial Cost, Land	$ 7,508
Initial Cost, Buildings and Improvements	6,601
Costs Capitalized Subsequent to Consolidation	6,525
Land	7,508
Buildings and Improvements	13,126
Total	20,634
Accumulated Depreciation (AD)	(6,960)
Total Cost Net of Accumulated Depreciation	13,674
Encumbrances	$ 0
Aimco Real Estate | Cedar Rim | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Apr. 1, 2000
Location	Newcastle, WA
Number of apartment communities | apartment_home	104
Initial Cost, Land	$ 761
Initial Cost, Buildings and Improvements	5,218
Costs Capitalized Subsequent to Consolidation	13,032
Land	761
Buildings and Improvements	18,250
Total	19,011
Accumulated Depreciation (AD)	(13,153)
Total Cost Net of Accumulated Depreciation	5,858
Encumbrances	$ 0
Aimco Real Estate | Charlesbank Apartment Homes | Continuing Operations
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
Number of apartment communities | apartment_home	44
Initial Cost, Land	$ 3,399
Initial Cost, Buildings and Improvements	11,726
Costs Capitalized Subsequent to Consolidation	821
Land	3,399
Buildings and Improvements	12,547
Total	15,946
Accumulated Depreciation (AD)	(2,404)
Total Cost Net of Accumulated Depreciation	13,542
Encumbrances	$ 7,718
Aimco Real Estate | Chestnut Hall | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Oct. 1, 2006
Location	Philadelphia, PA
Number of apartment communities | apartment_home	315
Initial Cost, Land	$ 12,338
Initial Cost, Buildings and Improvements	14,299
Costs Capitalized Subsequent to Consolidation	12,074
Land	12,338
Buildings and Improvements	26,373
Total	38,711
Accumulated Depreciation (AD)	(12,144)
Total Cost Net of Accumulated Depreciation	26,567
Encumbrances	$ 36,653
Aimco Real Estate | Chimneys of Cradle Rock | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jun. 1, 2004
Location	Columbia, MD
Number of apartment communities | apartment_home	198
Initial Cost, Land	$ 2,040
Initial Cost, Buildings and Improvements	8,108
Costs Capitalized Subsequent to Consolidation	1,116
Land	2,040
Buildings and Improvements	9,224
Total	11,264
Accumulated Depreciation (AD)	(4,206)
Total Cost Net of Accumulated Depreciation	7,058
Encumbrances	$ 0
Aimco Real Estate | Columbus Avenue | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Sep. 1, 2003
Location	New York, NY
Number of apartment communities | apartment_home	59
Initial Cost, Land	$ 35,527
Initial Cost, Buildings and Improvements	9,450
Costs Capitalized Subsequent to Consolidation	9,117
Land	35,527
Buildings and Improvements	18,567
Total	54,094
Accumulated Depreciation (AD)	(10,600)
Total Cost Net of Accumulated Depreciation	43,494
Encumbrances	$ 25,205
Aimco Real Estate | Creekside | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 1, 2000
Location	Denver, CO
Number of apartment communities | apartment_home	328
Initial Cost, Land	$ 3,189
Initial Cost, Buildings and Improvements	12,698
Costs Capitalized Subsequent to Consolidation	7,450
Land	3,189
Buildings and Improvements	20,148
Total	23,337
Accumulated Depreciation (AD)	(13,072)
Total Cost Net of Accumulated Depreciation	10,265
Encumbrances	$ 11,325
Aimco Real Estate | Crescent at West Hollywood, The | Continuing Operations
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
Number of apartment communities | apartment_home	130
Initial Cost, Land	$ 15,765
Initial Cost, Buildings and Improvements	10,215
Costs Capitalized Subsequent to Consolidation	8,411
Land	15,765
Buildings and Improvements	18,626
Total	34,391
Accumulated Depreciation (AD)	(12,166)
Total Cost Net of Accumulated Depreciation	22,225
Encumbrances	$ 40,000
Aimco Real Estate | Elm Creek | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 1, 1997
Location	Elmhurst, IL
Number of apartment communities | apartment_home	400
Initial Cost, Land	$ 5,910
Initial Cost, Buildings and Improvements	30,830
Costs Capitalized Subsequent to Consolidation	31,950
Land	5,910
Buildings and Improvements	62,780
Total	68,690
Accumulated Depreciation (AD)	(32,993)
Total Cost Net of Accumulated Depreciation	35,697
Encumbrances	$ 51,341
Aimco Real Estate | Evanston Place | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 1, 1997
Location	Evanston, IL
Number of apartment communities | apartment_home	190
Initial Cost, Land	$ 3,232
Initial Cost, Buildings and Improvements	25,546
Costs Capitalized Subsequent to Consolidation	16,214
Land	3,232
Buildings and Improvements	41,760
Total	44,992
Accumulated Depreciation (AD)	(19,152)
Total Cost Net of Accumulated Depreciation	25,840
Encumbrances	$ 0
Aimco Real Estate | Farmingdale | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Oct. 1, 2000
Location	Darien, IL
Number of apartment communities | apartment_home	240
Initial Cost, Land	$ 11,763
Initial Cost, Buildings and Improvements	15,174
Costs Capitalized Subsequent to Consolidation	11,173
Land	11,763
Buildings and Improvements	26,347
Total	38,110
Accumulated Depreciation (AD)	(13,618)
Total Cost Net of Accumulated Depreciation	24,492
Encumbrances	$ 13,106
Aimco Real Estate | Flamingo Towers | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 1, 1997
Location	Miami Beach, FL
Number of apartment communities | apartment_home	1,324
Initial Cost, Land	$ 32,427
Initial Cost, Buildings and Improvements	48,808
Costs Capitalized Subsequent to Consolidation	339,187
Land	32,427
Buildings and Improvements	387,995
Total	420,422
Accumulated Depreciation (AD)	(174,249)
Total Cost Net of Accumulated Depreciation	246,173
Encumbrances	$ 103,152
Aimco Real Estate | Four Quarters Habitat | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 6, 2006
Location	Miami, FL
Number of apartment communities | apartment_home	336
Initial Cost, Land	$ 2,379
Initial Cost, Buildings and Improvements	17,199
Costs Capitalized Subsequent to Consolidation	30,286
Land	2,379
Buildings and Improvements	47,485
Total	49,864
Accumulated Depreciation (AD)	(27,112)
Total Cost Net of Accumulated Depreciation	22,752
Encumbrances	$ 51,603
Aimco Real Estate | Foxchase | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Dec. 1, 1997
Location	Alexandria, VA
Number of apartment communities | apartment_home	2,113
Initial Cost, Land	$ 15,496
Initial Cost, Buildings and Improvements	96,062
Costs Capitalized Subsequent to Consolidation	52,254
Land	15,496
Buildings and Improvements	148,316
Total	163,812
Accumulated Depreciation (AD)	(85,298)
Total Cost Net of Accumulated Depreciation	78,514
Encumbrances	$ 223,626
Aimco Real Estate | Georgetown | Continuing Operations
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
Number of apartment communities | apartment_home	207
Initial Cost, Land	$ 12,351
Initial Cost, Buildings and Improvements	13,168
Costs Capitalized Subsequent to Consolidation	3,996
Land	12,351
Buildings and Improvements	17,164
Total	29,515
Accumulated Depreciation (AD)	(8,281)
Total Cost Net of Accumulated Depreciation	21,234
Encumbrances	$ 14,697
Aimco Real Estate | Georgetown II | Continuing Operations
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
Number of apartment communities | apartment_home	72
Initial Cost, Land	$ 4,577
Initial Cost, Buildings and Improvements	4,057
Costs Capitalized Subsequent to Consolidation	2,118
Land	4,577
Buildings and Improvements	6,175
Total	10,752
Accumulated Depreciation (AD)	(3,483)
Total Cost Net of Accumulated Depreciation	7,269
Encumbrances	$ 0
Aimco Real Estate | Heritage Park Escondido | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 2000
Location	Escondido, CA
Number of apartment communities | apartment_home	196
Initial Cost, Land	$ 1,055
Initial Cost, Buildings and Improvements	7,565
Costs Capitalized Subsequent to Consolidation	2,572
Land	1,055
Buildings and Improvements	10,137
Total	11,192
Accumulated Depreciation (AD)	(6,993)
Total Cost Net of Accumulated Depreciation	4,199
Encumbrances	$ 6,129
Aimco Real Estate | Heritage Park Livermore | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 2000
Location	Livermore, CA
Number of apartment communities | apartment_home	167
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	10,209
Costs Capitalized Subsequent to Consolidation	1,850
Land	0
Buildings and Improvements	12,059
Total	12,059
Accumulated Depreciation (AD)	(8,176)
Total Cost Net of Accumulated Depreciation	3,883
Encumbrances	$ 6,353
Aimco Real Estate | Heritage Village Anaheim | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 2000
Location	Anaheim, CA
Number of apartment communities | apartment_home	196
Initial Cost, Land	$ 1,832
Initial Cost, Buildings and Improvements	8,541
Costs Capitalized Subsequent to Consolidation	2,084
Land	1,832
Buildings and Improvements	10,625
Total	12,457
Accumulated Depreciation (AD)	(6,999)
Total Cost Net of Accumulated Depreciation	5,458
Encumbrances	$ 7,441
Aimco Real Estate | Hidden Cove | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 22, 1998
Location	Escondido, CA
Number of apartment communities | apartment_home	334
Initial Cost, Land	$ 3,043
Initial Cost, Buildings and Improvements	17,616
Costs Capitalized Subsequent to Consolidation	10,802
Land	3,043
Buildings and Improvements	28,418
Total	31,461
Accumulated Depreciation (AD)	(16,205)
Total Cost Net of Accumulated Depreciation	15,256
Encumbrances	$ 51,840
Aimco Real Estate | Hidden Cove II | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 7, 2007
Location	Escondido, CA
Number of apartment communities | apartment_home	118
Initial Cost, Land	$ 12,849
Initial Cost, Buildings and Improvements	6,530
Costs Capitalized Subsequent to Consolidation	5,260
Land	12,849
Buildings and Improvements	11,790
Total	24,639
Accumulated Depreciation (AD)	(5,263)
Total Cost Net of Accumulated Depreciation	19,376
Encumbrances	$ 20,160
Aimco Real Estate | Hillcreste | Continuing Operations
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
Number of apartment communities | apartment_home	315
Initial Cost, Land	$ 35,862
Initial Cost, Buildings and Improvements	47,216
Costs Capitalized Subsequent to Consolidation	13,194
Land	35,862
Buildings and Improvements	60,410
Total	96,272
Accumulated Depreciation (AD)	(27,374)
Total Cost Net of Accumulated Depreciation	68,898
Encumbrances	$ 63,479
Aimco Real Estate | Hillmeade | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Nov. 1, 1994
Location	Nashville, TN
Number of apartment communities | apartment_home	288
Initial Cost, Land	$ 2,872
Initial Cost, Buildings and Improvements	16,070
Costs Capitalized Subsequent to Consolidation	20,200
Land	2,872
Buildings and Improvements	36,270
Total	39,142
Accumulated Depreciation (AD)	(21,006)
Total Cost Net of Accumulated Depreciation	18,136
Encumbrances	$ 27,321
Aimco Real Estate | Horizons West Apartments | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 1, 2006
Location	Pacifica, CA
Number of apartment communities | apartment_home	78
Initial Cost, Land	$ 8,887
Initial Cost, Buildings and Improvements	6,377
Costs Capitalized Subsequent to Consolidation	1,634
Land	8,887
Buildings and Improvements	8,011
Total	16,898
Accumulated Depreciation (AD)	(3,689)
Total Cost Net of Accumulated Depreciation	13,209
Encumbrances	$ 0
Aimco Real Estate | Hunt Club | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Sep. 20, 2000
Location	Gaithersburg, MD
Number of apartment communities | apartment_home	336
Initial Cost, Land	$ 17,859
Initial Cost, Buildings and Improvements	13,149
Costs Capitalized Subsequent to Consolidation	14,154
Land	17,859
Buildings and Improvements	27,303
Total	45,162
Accumulated Depreciation (AD)	(16,083)
Total Cost Net of Accumulated Depreciation	29,079
Encumbrances	$ 0
Aimco Real Estate | Hyde Park Tower | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Oct. 1, 2004
Location	Chicago, IL
Number of apartment communities | apartment_home	155
Initial Cost, Land	$ 4,731
Initial Cost, Buildings and Improvements	14,927
Costs Capitalized Subsequent to Consolidation	12,334
Land	4,731
Buildings and Improvements	27,261
Total	31,992
Accumulated Depreciation (AD)	(9,569)
Total Cost Net of Accumulated Depreciation	22,423
Encumbrances	$ 12,620
Aimco Real Estate | Indian Oaks | Continuing Operations
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
Number of apartment communities | apartment_home	254
Initial Cost, Land	$ 24,523
Initial Cost, Buildings and Improvements	15,801
Costs Capitalized Subsequent to Consolidation	11,246
Land	24,523
Buildings and Improvements	27,047
Total	51,570
Accumulated Depreciation (AD)	(13,180)
Total Cost Net of Accumulated Depreciation	38,390
Encumbrances	$ 27,596
Aimco Real Estate | Indigo | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Aug. 1, 2016
Location	Redwood City, CA
Number of apartment communities | apartment_home	463
Initial Cost, Land	$ 26,932
Initial Cost, Buildings and Improvements	296,116
Costs Capitalized Subsequent to Consolidation	1,771
Land	26,932
Buildings and Improvements	297,887
Total	324,819
Accumulated Depreciation (AD)	(24,707)
Total Cost Net of Accumulated Depreciation	300,112
Encumbrances	$ 138,430
Aimco Real Estate | Island Club | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 2000
Location	Oceanside, CA
Number of apartment communities | apartment_home	592
Initial Cost, Land	$ 18,027
Initial Cost, Buildings and Improvements	28,654
Costs Capitalized Subsequent to Consolidation	18,740
Land	18,027
Buildings and Improvements	47,394
Total	65,421
Accumulated Depreciation (AD)	(30,320)
Total Cost Net of Accumulated Depreciation	35,101
Encumbrances	$ 94,967
Aimco Real Estate | Key Towers | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Apr. 1, 2001
Location	Alexandria, VA
Number of apartment communities | apartment_home	140
Initial Cost, Land	$ 1,526
Initial Cost, Buildings and Improvements	7,050
Costs Capitalized Subsequent to Consolidation	7,781
Land	1,526
Buildings and Improvements	14,831
Total	16,357
Accumulated Depreciation (AD)	(11,892)
Total Cost Net of Accumulated Depreciation	4,465
Encumbrances	$ 0
Aimco Real Estate | Lakeside | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 1999
Location	Lisle, IL
Number of apartment communities | apartment_home	568
Initial Cost, Land	$ 5,840
Initial Cost, Buildings and Improvements	27,937
Costs Capitalized Subsequent to Consolidation	22,408
Land	5,840
Buildings and Improvements	50,345
Total	56,185
Accumulated Depreciation (AD)	(33,582)
Total Cost Net of Accumulated Depreciation	22,603
Encumbrances	$ 25,090
Aimco Real Estate | Latrobe | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 3, 2003
Location	Washington, DC
Number of apartment communities | apartment_home	175
Initial Cost, Land	$ 3,459
Initial Cost, Buildings and Improvements	9,103
Costs Capitalized Subsequent to Consolidation	12,715
Land	3,459
Buildings and Improvements	21,818
Total	25,277
Accumulated Depreciation (AD)	(11,916)
Total Cost Net of Accumulated Depreciation	13,361
Encumbrances	$ 26,758
Aimco Real Estate | Laurel Crossing | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 6, 2006
Location	San Mateo, CA
Number of apartment communities | apartment_home	418
Initial Cost, Land	$ 49,474
Initial Cost, Buildings and Improvements	17,756
Costs Capitalized Subsequent to Consolidation	14,166
Land	49,474
Buildings and Improvements	31,922
Total	81,396
Accumulated Depreciation (AD)	(15,757)
Total Cost Net of Accumulated Depreciation	65,639
Encumbrances	$ 0
Aimco Real Estate | Lincoln Place (5) | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 2004
Location	Venice, CA
Number of apartment communities | apartment_home	795
Initial Cost, Land	$ 128,332
Initial Cost, Buildings and Improvements	10,439
Costs Capitalized Subsequent to Consolidation	337,267
Land	44,197
Buildings and Improvements	347,706
Total	391,903
Accumulated Depreciation (AD)	(121,677)
Total Cost Net of Accumulated Depreciation	270,226
Encumbrances	$ 187,723
Aimco Real Estate | Locust on the Park | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	May 1, 2018
Location	Philadelphia, PA
Number of apartment communities | apartment_home	152
Initial Cost, Land	$ 5,292
Initial Cost, Buildings and Improvements	53,823
Costs Capitalized Subsequent to Consolidation	2,474
Land	5,292
Buildings and Improvements	56,297
Total	61,589
Accumulated Depreciation (AD)	(1,183)
Total Cost Net of Accumulated Depreciation	60,406
Encumbrances	$ 35,728
Aimco Real Estate | Lodge at Chattahoochee, The | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 1999
Location	Sandy Springs, GA
Number of apartment communities | apartment_home	312
Initial Cost, Land	$ 2,335
Initial Cost, Buildings and Improvements	16,370
Costs Capitalized Subsequent to Consolidation	16,809
Land	2,335
Buildings and Improvements	33,179
Total	35,514
Accumulated Depreciation (AD)	(22,375)
Total Cost Net of Accumulated Depreciation	13,139
Encumbrances	$ 0
Aimco Real Estate | Malibu Canyon | Continuing Operations
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
Number of apartment communities | apartment_home	698
Initial Cost, Land	$ 69,834
Initial Cost, Buildings and Improvements	53,438
Costs Capitalized Subsequent to Consolidation	37,919
Land	69,834
Buildings and Improvements	91,357
Total	161,191
Accumulated Depreciation (AD)	(45,222)
Total Cost Net of Accumulated Depreciation	115,969
Encumbrances	$ 105,367
Aimco Real Estate | Mariners Cove | Continuing Operations
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
Number of apartment communities | apartment_home	500
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	66,861
Costs Capitalized Subsequent to Consolidation	13,317
Land	0
Buildings and Improvements	80,178
Total	80,178
Accumulated Depreciation (AD)	(39,035)
Total Cost Net of Accumulated Depreciation	41,143
Encumbrances	$ 0
Aimco Real Estate | Meadow Creek | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 1, 1994
Location	Boulder, CO
Number of apartment communities | apartment_home	332
Initial Cost, Land	$ 1,435
Initial Cost, Buildings and Improvements	24,533
Costs Capitalized Subsequent to Consolidation	9,602
Land	1,435
Buildings and Improvements	34,135
Total	35,570
Accumulated Depreciation (AD)	(19,285)
Total Cost Net of Accumulated Depreciation	16,285
Encumbrances	$ 0
Aimco Real Estate | Merrill House | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 3, 2000
Location	Falls Church, VA
Number of apartment communities | apartment_home	159
Initial Cost, Land	$ 1,836
Initial Cost, Buildings and Improvements	10,831
Costs Capitalized Subsequent to Consolidation	7,657
Land	1,836
Buildings and Improvements	18,488
Total	20,324
Accumulated Depreciation (AD)	(10,492)
Total Cost Net of Accumulated Depreciation	9,832
Encumbrances	$ 0
Aimco Real Estate | Mezzo | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Mar. 15, 2015
Location	Atlanta, GA
Number of apartment communities | apartment_home	94
Initial Cost, Land	$ 4,292
Initial Cost, Buildings and Improvements	34,178
Costs Capitalized Subsequent to Consolidation	1,250
Land	4,292
Buildings and Improvements	35,428
Total	39,720
Accumulated Depreciation (AD)	(5,484)
Total Cost Net of Accumulated Depreciation	34,236
Encumbrances	$ 23,496
Aimco Real Estate | Monterey Grove | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jun. 1, 2008
Location	San Jose, CA
Number of apartment communities | apartment_home	224
Initial Cost, Land	$ 34,325
Initial Cost, Buildings and Improvements	21,939
Costs Capitalized Subsequent to Consolidation	8,674
Land	34,325
Buildings and Improvements	30,613
Total	64,938
Accumulated Depreciation (AD)	(12,039)
Total Cost Net of Accumulated Depreciation	52,899
Encumbrances	$ 0
Aimco Real Estate | Ocean House on Prospect | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Apr. 1, 2013
Location	La Jolla, CA
Number of apartment communities | apartment_home	53
Initial Cost, Land	$ 12,528
Initial Cost, Buildings and Improvements	18,805
Costs Capitalized Subsequent to Consolidation	15,089
Land	12,528
Buildings and Improvements	33,894
Total	46,422
Accumulated Depreciation (AD)	(6,592)
Total Cost Net of Accumulated Depreciation	39,830
Encumbrances	$ 12,745
Aimco Real Estate | One Canal | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Sep. 13, 2013
Location	Boston, MA
Number of apartment communities | apartment_home	310
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	15,873
Costs Capitalized Subsequent to Consolidation	179,912
Land	0
Buildings and Improvements	195,785
Total	195,785
Accumulated Depreciation (AD)	(20,623)
Total Cost Net of Accumulated Depreciation	175,162
Encumbrances	$ 110,310
Aimco Real Estate | Pacific Bay Vistas (5) | Continuing Operations
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
Number of apartment communities | apartment_home	308
Initial Cost, Land	$ 28,694
Initial Cost, Buildings and Improvements	62,460
Costs Capitalized Subsequent to Consolidation	39,067
Land	23,354
Buildings and Improvements	101,527
Total	124,881
Accumulated Depreciation (AD)	(35,131)
Total Cost Net of Accumulated Depreciation	89,750
Encumbrances	$ 67,826
Aimco Real Estate | Pacifica Park | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 6, 2006
Location	Pacifica, CA
Number of apartment communities | apartment_home	104
Initial Cost, Land	$ 12,970
Initial Cost, Buildings and Improvements	6,579
Costs Capitalized Subsequent to Consolidation	7,879
Land	12,970
Buildings and Improvements	14,458
Total	27,428
Accumulated Depreciation (AD)	(6,565)
Total Cost Net of Accumulated Depreciation	20,863
Encumbrances	$ 28,613
Aimco Real Estate | Palazzo at Park La Brea, The | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Feb. 4, 2004
Location	Los Angeles, CA
Number of apartment communities | apartment_home	521
Initial Cost, Land	$ 48,362
Initial Cost, Buildings and Improvements	125,464
Costs Capitalized Subsequent to Consolidation	45,176
Land	48,362
Buildings and Improvements	170,640
Total	219,002
Accumulated Depreciation (AD)	(80,075)
Total Cost Net of Accumulated Depreciation	138,927
Encumbrances	$ 168,654
Aimco Real Estate | Palazzo East at Park La Brea, The | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Mar. 1, 2005
Location	Los Angeles, CA
Number of apartment communities | apartment_home	611
Initial Cost, Land	$ 72,578
Initial Cost, Buildings and Improvements	136,503
Costs Capitalized Subsequent to Consolidation	19,328
Land	72,578
Buildings and Improvements	155,831
Total	228,409
Accumulated Depreciation (AD)	(72,709)
Total Cost Net of Accumulated Depreciation	155,700
Encumbrances	$ 196,109
Aimco Real Estate | Parc Mosaic | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Dec. 14, 2014
Location	Boulder, CO
Number of apartment communities | apartment_home	226
Initial Cost, Land	$ 15,300
Initial Cost, Buildings and Improvements	0
Costs Capitalized Subsequent to Consolidation	53,638
Land	15,300
Buildings and Improvements	53,638
Total	68,938
Accumulated Depreciation (AD)	0
Total Cost Net of Accumulated Depreciation	68,938
Encumbrances	$ 0
Aimco Real Estate | Park Towne Place | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Apr. 1, 2000
Location	Philadelphia, PA
Number of apartment communities | apartment_home	940
Initial Cost, Land	$ 10,472
Initial Cost, Buildings and Improvements	47,301
Costs Capitalized Subsequent to Consolidation	345,748
Land	10,472
Buildings and Improvements	393,049
Total	403,521
Accumulated Depreciation (AD)	(119,350)
Total Cost Net of Accumulated Depreciation	284,171
Encumbrances	$ 200,000
Aimco Real Estate | Pathfinder Village | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 6, 2006
Location	Fremont, CA
Number of apartment communities | apartment_home	246
Initial Cost, Land	$ 19,595
Initial Cost, Buildings and Improvements	14,838
Costs Capitalized Subsequent to Consolidation	18,457
Land	19,595
Buildings and Improvements	33,295
Total	52,890
Accumulated Depreciation (AD)	(14,518)
Total Cost Net of Accumulated Depreciation	38,372
Encumbrances	$ 55,000
Aimco Real Estate | Peachtree Park | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 1, 1996
Location	Atlanta, GA
Number of apartment communities | apartment_home	303
Initial Cost, Land	$ 4,684
Initial Cost, Buildings and Improvements	11,713
Costs Capitalized Subsequent to Consolidation	14,045
Land	4,684
Buildings and Improvements	25,758
Total	30,442
Accumulated Depreciation (AD)	(16,449)
Total Cost Net of Accumulated Depreciation	13,993
Encumbrances	$ 27,800
Aimco Real Estate | Plantation Gardens | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 1999
Location	Plantation, FL
Number of apartment communities | apartment_home	372
Initial Cost, Land	$ 3,773
Initial Cost, Buildings and Improvements	19,443
Costs Capitalized Subsequent to Consolidation	25,655
Land	3,773
Buildings and Improvements	45,098
Total	48,871
Accumulated Depreciation (AD)	(27,273)
Total Cost Net of Accumulated Depreciation	21,598
Encumbrances	$ 0
Aimco Real Estate | Post Ridge | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 1, 2000
Location	Nashville, TN
Number of apartment communities | apartment_home	150
Initial Cost, Land	$ 1,883
Initial Cost, Buildings and Improvements	6,712
Costs Capitalized Subsequent to Consolidation	4,537
Land	1,883
Buildings and Improvements	11,249
Total	13,132
Accumulated Depreciation (AD)	(7,401)
Total Cost Net of Accumulated Depreciation	5,731
Encumbrances	$ 0
Aimco Real Estate | Preserve at Marin | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Aug. 17, 2011
Location	Corte Madera, CA
Number of apartment communities | apartment_home	126
Initial Cost, Land	$ 18,179
Initial Cost, Buildings and Improvements	30,132
Costs Capitalized Subsequent to Consolidation	84,629
Land	18,179
Buildings and Improvements	114,761
Total	132,940
Accumulated Depreciation (AD)	(26,039)
Total Cost Net of Accumulated Depreciation	106,901
Encumbrances	$ 36,260
Aimco Real Estate | Ravensworth Towers | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jun. 1, 2004
Location	Annandale, VA
Number of apartment communities | apartment_home	219
Initial Cost, Land	$ 3,455
Initial Cost, Buildings and Improvements	17,157
Costs Capitalized Subsequent to Consolidation	4,490
Land	3,455
Buildings and Improvements	21,647
Total	25,102
Accumulated Depreciation (AD)	(14,617)
Total Cost Net of Accumulated Depreciation	10,485
Encumbrances	$ 20,342
Aimco Real Estate | River Club,The | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Apr. 5, 2005
Location	Edgewater, NJ
Number of apartment communities | apartment_home	266
Initial Cost, Land	$ 30,579
Initial Cost, Buildings and Improvements	30,638
Costs Capitalized Subsequent to Consolidation	7,475
Land	30,579
Buildings and Improvements	38,113
Total	68,692
Accumulated Depreciation (AD)	(17,293)
Total Cost Net of Accumulated Depreciation	51,399
Encumbrances	$ 60,000
Aimco Real Estate | Riverloft | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Oct. 1, 1999
Location	Philadelphia, PA
Number of apartment communities | apartment_home	184
Initial Cost, Land	$ 2,120
Initial Cost, Buildings and Improvements	11,286
Costs Capitalized Subsequent to Consolidation	35,086
Land	2,120
Buildings and Improvements	46,372
Total	48,492
Accumulated Depreciation (AD)	(23,386)
Total Cost Net of Accumulated Depreciation	25,106
Encumbrances	$ 7,680
Aimco Real Estate | Rosewood | Continuing Operations
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
Number of apartment communities | apartment_home	152
Initial Cost, Land	$ 12,430
Initial Cost, Buildings and Improvements	8,060
Costs Capitalized Subsequent to Consolidation	5,754
Land	12,430
Buildings and Improvements	13,814
Total	26,244
Accumulated Depreciation (AD)	(6,984)
Total Cost Net of Accumulated Depreciation	19,260
Encumbrances	$ 0
Aimco Real Estate | Royal Crest Estates | Continuing Operations
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
Number of apartment communities | apartment_home	492
Initial Cost, Land	$ 22,433
Initial Cost, Buildings and Improvements	24,095
Costs Capitalized Subsequent to Consolidation	5,512
Land	22,433
Buildings and Improvements	29,607
Total	52,040
Accumulated Depreciation (AD)	(20,050)
Total Cost Net of Accumulated Depreciation	31,990
Encumbrances	$ 0
Aimco Real Estate | Royal Crest Estates | Continuing Operations
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
Number of apartment communities | apartment_home	902
Initial Cost, Land	$ 68,230
Initial Cost, Buildings and Improvements	45,562
Costs Capitalized Subsequent to Consolidation	15,751
Land	68,230
Buildings and Improvements	61,313
Total	129,543
Accumulated Depreciation (AD)	(41,440)
Total Cost Net of Accumulated Depreciation	88,103
Encumbrances	$ 71,957
Aimco Real Estate | Royal Crest Estates | Continuing Operations
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
Number of apartment communities | apartment_home	473
Initial Cost, Land	$ 25,178
Initial Cost, Buildings and Improvements	28,786
Costs Capitalized Subsequent to Consolidation	13,490
Land	25,178
Buildings and Improvements	42,276
Total	67,454
Accumulated Depreciation (AD)	(26,610)
Total Cost Net of Accumulated Depreciation	40,844
Encumbrances	$ 0
Aimco Real Estate | Royal Crest Estates | Continuing Operations
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
Number of apartment communities | apartment_home	588
Initial Cost, Land	$ 51,292
Initial Cost, Buildings and Improvements	36,808
Costs Capitalized Subsequent to Consolidation	27,916
Land	51,292
Buildings and Improvements	64,724
Total	116,016
Accumulated Depreciation (AD)	(36,132)
Total Cost Net of Accumulated Depreciation	79,884
Encumbrances	$ 0
Aimco Real Estate | Saybrook Point | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Dec. 14, 2014
Location	San Jose, CA
Number of apartment communities | apartment_home	324
Initial Cost, Land	$ 32,842
Initial Cost, Buildings and Improvements	84,457
Costs Capitalized Subsequent to Consolidation	25,729
Land	32,842
Buildings and Improvements	110,186
Total	143,028
Accumulated Depreciation (AD)	(14,179)
Total Cost Net of Accumulated Depreciation	128,849
Encumbrances	$ 62,329
Aimco Real Estate | Shenandoah Crossing | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Sep. 20, 2000
Location	Fairfax, VA
Number of apartment communities | apartment_home	640
Initial Cost, Land	$ 18,200
Initial Cost, Buildings and Improvements	57,198
Costs Capitalized Subsequent to Consolidation	25,345
Land	18,200
Buildings and Improvements	82,543
Total	100,743
Accumulated Depreciation (AD)	(58,302)
Total Cost Net of Accumulated Depreciation	42,441
Encumbrances	$ 58,565
Aimco Real Estate | SouthStar Lofts | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	May 1, 2018
Location	Philadelphia, PA
Number of apartment communities | apartment_home	85
Initial Cost, Land	$ 1,780
Initial Cost, Buildings and Improvements	37,428
Costs Capitalized Subsequent to Consolidation	402
Land	1,780
Buildings and Improvements	37,830
Total	39,610
Accumulated Depreciation (AD)	(836)
Total Cost Net of Accumulated Depreciation	38,774
Encumbrances	$ 30,197
Aimco Real Estate | Springwoods at Lake Ridge | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jul. 1, 2002
Location	Woodbridge, VA
Number of apartment communities | apartment_home	180
Initial Cost, Land	$ 5,587
Initial Cost, Buildings and Improvements	7,284
Costs Capitalized Subsequent to Consolidation	3,642
Land	5,587
Buildings and Improvements	10,926
Total	16,513
Accumulated Depreciation (AD)	(4,606)
Total Cost Net of Accumulated Depreciation	11,907
Encumbrances	$ 0
Aimco Real Estate | St. George Villas | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jan. 6, 2006
Location	St. George, SC
Number of apartment communities | apartment_home	40
Initial Cost, Land	$ 107
Initial Cost, Buildings and Improvements	1,025
Costs Capitalized Subsequent to Consolidation	410
Land	107
Buildings and Improvements	1,435
Total	1,542
Accumulated Depreciation (AD)	(1,256)
Total Cost Net of Accumulated Depreciation	286
Encumbrances	$ 314
Aimco Real Estate | Sterling Apartment Homes, The | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Oct. 1, 1999
Location	Philadelphia, PA
Number of apartment communities | apartment_home	534
Initial Cost, Land	$ 8,871
Initial Cost, Buildings and Improvements	55,365
Costs Capitalized Subsequent to Consolidation	120,426
Land	8,871
Buildings and Improvements	175,791
Total	184,662
Accumulated Depreciation (AD)	(82,367)
Total Cost Net of Accumulated Depreciation	102,295
Encumbrances	$ 144,030
Aimco Real Estate | Stone Creek Club | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Sep. 20, 2000
Location	Germantown, MD
Number of apartment communities | apartment_home	240
Initial Cost, Land	$ 13,593
Initial Cost, Buildings and Improvements	9,347
Costs Capitalized Subsequent to Consolidation	8,078
Land	13,593
Buildings and Improvements	17,425
Total	31,018
Accumulated Depreciation (AD)	(12,553)
Total Cost Net of Accumulated Depreciation	18,465
Encumbrances	$ 0
Aimco Real Estate | The Left Bank | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	May 1, 2018
Location	Philadelphia, PA
Number of apartment communities | apartment_home	282
Initial Cost, Land	$ 0
Initial Cost, Buildings and Improvements	130,893
Costs Capitalized Subsequent to Consolidation	3,053
Land	0
Buildings and Improvements	133,946
Total	133,946
Accumulated Depreciation (AD)	(2,879)
Total Cost Net of Accumulated Depreciation	131,067
Encumbrances	$ 82,532
Aimco Real Estate | Timbers at Long Reach Apartment Homes | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Apr. 5, 2005
Location	Columbia, MD
Number of apartment communities | apartment_home	178
Initial Cost, Land	$ 2,430
Initial Cost, Buildings and Improvements	12,181
Costs Capitalized Subsequent to Consolidation	1,705
Land	2,430
Buildings and Improvements	13,886
Total	16,316
Accumulated Depreciation (AD)	(8,182)
Total Cost Net of Accumulated Depreciation	8,134
Encumbrances	$ 0
Aimco Real Estate | Towers Of Westchester Park, The | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jan. 6, 2006
Location	College Park, MD
Number of apartment communities | apartment_home	303
Initial Cost, Land	$ 15,198
Initial Cost, Buildings and Improvements	22,029
Costs Capitalized Subsequent to Consolidation	13,936
Land	15,198
Buildings and Improvements	35,965
Total	51,163
Accumulated Depreciation (AD)	(18,825)
Total Cost Net of Accumulated Depreciation	32,338
Encumbrances	$ 23,232
Aimco Real Estate | Township At Highlands | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Town Home
Date Consolidated	Nov. 1, 1996
Location	Centennial, CO
Number of apartment communities | apartment_home	161
Initial Cost, Land	$ 1,536
Initial Cost, Buildings and Improvements	9,773
Costs Capitalized Subsequent to Consolidation	9,280
Land	1,536
Buildings and Improvements	19,053
Total	20,589
Accumulated Depreciation (AD)	(12,181)
Total Cost Net of Accumulated Depreciation	8,408
Encumbrances	$ 13,557
Aimco Real Estate | Tremont | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Dec. 14, 2014
Location	Atlanta, GA
Number of apartment communities | apartment_home	78
Initial Cost, Land	$ 5,274
Initial Cost, Buildings and Improvements	18,011
Costs Capitalized Subsequent to Consolidation	2,746
Land	5,274
Buildings and Improvements	20,757
Total	26,031
Accumulated Depreciation (AD)	(3,110)
Total Cost Net of Accumulated Depreciation	22,921
Encumbrances	$ 0
Aimco Real Estate | Twin Lake Towers | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Oct. 1, 1999
Location	Westmont, IL
Number of apartment communities | apartment_home	399
Initial Cost, Land	$ 3,268
Initial Cost, Buildings and Improvements	18,763
Costs Capitalized Subsequent to Consolidation	37,904
Land	3,268
Buildings and Improvements	56,667
Total	59,935
Accumulated Depreciation (AD)	(43,106)
Total Cost Net of Accumulated Depreciation	16,829
Encumbrances	$ 44,906
Aimco Real Estate | Vantage Pointe | Continuing Operations
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
Number of apartment communities | apartment_home	96
Initial Cost, Land	$ 4,748
Initial Cost, Buildings and Improvements	10,089
Costs Capitalized Subsequent to Consolidation	2,314
Land	4,748
Buildings and Improvements	12,403
Total	17,151
Accumulated Depreciation (AD)	(5,294)
Total Cost Net of Accumulated Depreciation	11,857
Encumbrances	$ 2,746
Aimco Real Estate | Villa Del Sol | Continuing Operations
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
Number of apartment communities | apartment_home	120
Initial Cost, Land	$ 7,476
Initial Cost, Buildings and Improvements	4,861
Costs Capitalized Subsequent to Consolidation	4,553
Land	7,476
Buildings and Improvements	9,414
Total	16,890
Accumulated Depreciation (AD)	(5,216)
Total Cost Net of Accumulated Depreciation	11,674
Encumbrances	$ 10,582
Aimco Real Estate | Villas at Park La Brea, The | Continuing Operations
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
Number of apartment communities | apartment_home	250
Initial Cost, Land	$ 8,630
Initial Cost, Buildings and Improvements	48,871
Costs Capitalized Subsequent to Consolidation	16,008
Land	8,630
Buildings and Improvements	64,879
Total	73,509
Accumulated Depreciation (AD)	(30,510)
Total Cost Net of Accumulated Depreciation	42,999
Encumbrances	$ 53,868
Aimco Real Estate | Villas of Pasadena | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Mid Rise
Date Consolidated	Jan. 6, 2006
Location	Pasadena, CA
Number of apartment communities | apartment_home	92
Initial Cost, Land	$ 9,693
Initial Cost, Buildings and Improvements	6,818
Costs Capitalized Subsequent to Consolidation	4,493
Land	9,693
Buildings and Improvements	11,311
Total	21,004
Accumulated Depreciation (AD)	(4,397)
Total Cost Net of Accumulated Depreciation	16,607
Encumbrances	$ 0
Aimco Real Estate | Vivo | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Jun. 15, 2016
Location	Cambridge, MA
Number of apartment communities | apartment_home	91
Initial Cost, Land	$ 6,450
Initial Cost, Buildings and Improvements	35,974
Costs Capitalized Subsequent to Consolidation	5,590
Land	6,450
Buildings and Improvements	41,564
Total	48,014
Accumulated Depreciation (AD)	(8,694)
Total Cost Net of Accumulated Depreciation	39,320
Encumbrances	$ 20,310
Aimco Real Estate | Waterford Village | Continuing Operations
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
Number of apartment communities | apartment_home	588
Initial Cost, Land	$ 29,110
Initial Cost, Buildings and Improvements	28,101
Costs Capitalized Subsequent to Consolidation	8,222
Land	29,110
Buildings and Improvements	36,323
Total	65,433
Accumulated Depreciation (AD)	(26,540)
Total Cost Net of Accumulated Depreciation	38,893
Encumbrances	$ 35,269
Aimco Real Estate | Waterways Village | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Jun. 1, 1997
Location	Aventura, FL
Number of apartment communities | apartment_home	180
Initial Cost, Land	$ 4,504
Initial Cost, Buildings and Improvements	11,064
Costs Capitalized Subsequent to Consolidation	15,205
Land	4,504
Buildings and Improvements	26,269
Total	30,773
Accumulated Depreciation (AD)	(12,394)
Total Cost Net of Accumulated Depreciation	18,379
Encumbrances	$ 13,168
Aimco Real Estate | Waverly Apartments | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	Aug. 1, 2008
Location	Brighton, MA
Number of apartment communities | apartment_home	103
Initial Cost, Land	$ 7,920
Initial Cost, Buildings and Improvements	11,347
Costs Capitalized Subsequent to Consolidation	6,299
Land	7,920
Buildings and Improvements	17,646
Total	25,566
Accumulated Depreciation (AD)	(6,323)
Total Cost Net of Accumulated Depreciation	19,243
Encumbrances	$ 11,515
Aimco Real Estate | Wexford Village | Continuing Operations
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
Number of apartment communities | apartment_home	264
Initial Cost, Land	$ 6,349
Initial Cost, Buildings and Improvements	17,939
Costs Capitalized Subsequent to Consolidation	4,245
Land	6,349
Buildings and Improvements	22,184
Total	28,533
Accumulated Depreciation (AD)	(12,980)
Total Cost Net of Accumulated Depreciation	15,553
Encumbrances	$ 0
Aimco Real Estate | Willow Bend | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	Garden
Date Consolidated	May 8, 1998
Location	Rolling Meadows, IL
Number of apartment communities | apartment_home	328
Initial Cost, Land	$ 2,717
Initial Cost, Buildings and Improvements	15,437
Costs Capitalized Subsequent to Consolidation	19,609
Land	2,717
Buildings and Improvements	35,046
Total	37,763
Accumulated Depreciation (AD)	(23,492)
Total Cost Net of Accumulated Depreciation	14,271
Encumbrances	$ 33,175
Aimco Real Estate | Windrift | Continuing Operations
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
Number of apartment communities | apartment_home	404
Initial Cost, Land	$ 24,960
Initial Cost, Buildings and Improvements	17,590
Costs Capitalized Subsequent to Consolidation	21,487
Land	24,960
Buildings and Improvements	39,077
Total	64,037
Accumulated Depreciation (AD)	(23,762)
Total Cost Net of Accumulated Depreciation	40,275
Encumbrances	$ 0
Aimco Real Estate | Windsor Park | Continuing Operations
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
Number of apartment communities | apartment_home	220
Initial Cost, Land	$ 4,279
Initial Cost, Buildings and Improvements	15,970
Costs Capitalized Subsequent to Consolidation	6,217
Land	4,279
Buildings and Improvements	22,187
Total	26,466
Accumulated Depreciation (AD)	(13,378)
Total Cost Net of Accumulated Depreciation	13,088
Encumbrances	$ 0
Aimco Real Estate | Yacht Club at Brickell | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Apartment Type	High Rise
Date Consolidated	Dec. 24, 2003
Location	Miami, FL
Number of apartment communities | apartment_home	357
Initial Cost, Land	$ 31,362
Initial Cost, Buildings and Improvements	32,214
Costs Capitalized Subsequent to Consolidation	16,715
Land	31,362
Buildings and Improvements	48,929
Total	80,291
Accumulated Depreciation (AD)	(17,513)
Total Cost Net of Accumulated Depreciation	62,778
Encumbrances	$ 44,219
Aimco Real Estate | Yorktown Apartments | Continuing Operations
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
Number of apartment communities | apartment_home	364
Initial Cost, Land	$ 3,055
Initial Cost, Buildings and Improvements	18,162
Costs Capitalized Subsequent to Consolidation	52,436
Land	3,055
Buildings and Improvements	70,598
Total	73,653
Accumulated Depreciation (AD)	(29,697)
Total Cost Net of Accumulated Depreciation	43,956
Encumbrances	$ 38,280
Aimco Real Estate | Other | Continuing Operations
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation [Line Items]
Number of apartment communities | apartment_home	0
Initial Cost, Land	$ 5,135
Initial Cost, Buildings and Improvements	0
Costs Capitalized Subsequent to Consolidation	20,914
Land	5,135
Buildings and Improvements	20,914
Total	26,049
Accumulated Depreciation (AD)	0
Total Cost Net of Accumulated Depreciation	26,049
Encumbrances	$ 0

Real Estate and Accumulated D_3

Real Estate and Accumulated Depreciation - Summary Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Asset Management
Real Estate
Balance at beginning of year	$ 551,124	$ 555,049	$ 562,589
Additions during the year:
Capital additions	4,226	8,255	8,909
Deductions during the year:
Casualty and other write-offs	6,603	(1,711)	(2,116)
Amounts related to assets held for sale	0	0	(2,801)
Sales	(561,953)	(10,469)	(11,532)
Balance at end of year	0	551,124	555,049
Accumulated Depreciation
Balance at beginning of year	326,251	309,401	289,574
Additions during the year
Depreciation	14,325	24,090	24,704
Deductions during the year:
Casualty and other write-offs	6,704	(2,480)	(68)
Amounts related to assets held for sale	0	0	(1,525)
Sales	(347,280)	(4,760)	(3,284)
Balance at end of year	0	326,251	309,401
Write-off of fully depreciated assets	6,700	1,800
Aimco Real Estate
Real Estate
Balance at beginning of year	7,927,753	7,931,117	7,744,894
Additions during the year:
Acquisitions	501,009	16,687	333,174
Capital additions	344,501	345,974	329,697
Deductions during the year:
Casualty and other write-offs	(58,152)	(106,590)	(170,744)
Provision for real estate impairment loss	0	(35,881)	0
Amounts related to assets held for sale	(83,905)	(38,208)	0
Sales	(322,616)	(185,346)	(305,904)
Balance at end of year	8,308,590	7,927,753	7,931,117
Accumulated Depreciation
Balance at beginning of year	2,522,358	2,421,357	2,488,448
Additions during the year
Depreciation	339,883	320,870	287,661
Deductions during the year:
Casualty and other write-offs	(57,067)	(106,521)	(169,098)
Amounts related to assets held for sale	(41,717)	(20,383)	0
Sales	(178,342)	(92,965)	(185,654)
Balance at end of year	2,585,115	2,522,358	2,421,357
Write-off of fully depreciated assets	$ 54,500	$ 106,400	$ 167,900

Uncategorized Items - aiv-20181

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (65,710,000)
AIMCO Properties, LP [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(65,710,000)
AIMCO Properties, LP [Member] | Limited Partner [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(3,028,000)
AIMCO Properties, LP [Member] | Partners Capital Attributable To The Partnership [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(65,710,000)
AIMCO Properties, LP [Member] | General Partner and Special Limited Partner [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(62,682,000)
Noncontrolling Interest [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(3,028,000)
Accumulated Distributions in Excess of Net Income [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	(62,682,000)
Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (62,682,000)