Significant Transactions - Summarized Information Regarding Apartment Communities Sold (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($) community Property apartment_home	Dec. 31, 2017 USD ($) community Property apartment_home	Dec. 31, 2016 USD ($) Property apartment_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