Discontinued Operations - (Details Textual)	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) Property	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) Land Property	Jun. 30, 2020 USD ($)
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Number of leased property | Property	4		4
Number of vacant land parcel | Land			1
Sales-type lease, risk strategy, residual asset			we have rights in accordance with the individual lease agreements to protect the value of our leased properties.
Interest income	$ 15,684,000	$ 2,303,000	$ 31,656,000	$ 6,292,000
Other Assets [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Accounts receivable from Aimco	17,000,000		17,000,000
Accrued Liability [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Accounts payable from Aimco	3,000,000		3,000,000
Interest Income [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Interest income	6,900,000		13,900,000
General and Administrative Expense [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Reduction to Compensation Related Costs Recognized	$ 1,500		2,900
AIMCO [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Note Receivable issue from Aimco			$ 534,000,000
Note maturity date			Jan. 31, 2024
Note interest rate	5.20%		5.20%
Note frequency of periodic payment			quarterly
Minimum [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Lessor, sales-type lease, term of contract	10 years		10 years
Maximum [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Lessor, sales-type lease, term of contract	25 years		25 years
Property Management Agreement [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Revenue	$ 1,600,000		$ 3,300,000
Master Service Agreement [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Master lease agreement term			18 months
Master lease agreement commencement date			Jan. 01, 2021
Sales-type lease income	6,500,000		$ 12,900,000
Sales-type lease cash payments	6,700,000		13,300,000
Gain of Derecognition of Properties	$ 3,400,000		$ 87,100,000