Debt - Credit Facilities (Details)	Dec. 11, 2020 USD ($)	Sep. 09, 2020 USD ($) community	Aug. 31, 2020 USD ($) community	Mar. 31, 2020 USD ($) community	Mar. 20, 2020 USD ($) community	Mar. 19, 2020 USD ($) community	Jan. 31, 2020 USD ($) community	Aug. 29, 2019 USD ($) community	May 07, 2019 USD ($) community	Dec. 31, 2020 USD ($)	Dec. 05, 2018 USD ($)
First Mortgage Financing
Line of Credit Facility [Line Items]
Debt face amount		$ 156,500,000	$ 191,300,000	$ 73,100,000
First Mortgage Financing | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate basis		2.54%	2.49%	2.10%	2.50%	2.25%	2.09%	2.17%	2.23%
Fifth Amended and Restated Credit Agreement | Line of Credit
Line of Credit Facility [Line Items]
Line of credit			$ 166,400,000
Revolving Credit Facility | Fifth Amended and Restated Credit Agreement | Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity											$ 250,000,000.0
Letters of credit outstanding										$ 0
Current borrowing capacity										22,200,000
Revolving Credit Facility | Fifth Amended and Restated Credit Agreement | Line of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate basis			2.75%
Revolving Credit Facility | Fifth Amended and Restated Credit Agreement | Line of Credit | LIBOR | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate basis			2.25%
Revolving Credit Facility | Fifth Amended and Restated Credit Agreement | Line of Credit | LIBOR | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate basis			3.25%
Revolving Credit Facility | Credit Agreement with Capital One, National Association | Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity	$ 80,000,000
Commitment fee percentage	0.25%
Revolving Credit Facility | Credit Agreement with Capital One, National Association | Line of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate basis	2.75%
Letter of credit sublimit | Fifth Amended and Restated Credit Agreement | Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity											60,000,000.0
Letters of credit outstanding										40,400,000
Current borrowing capacity										22,200,000
Swingline Line of Credit | Fifth Amended and Restated Credit Agreement | Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity											$ 50,000,000.0
Letters of credit collateral | Fifth Amended and Restated Credit Agreement | Line of Credit
Line of Credit Facility [Line Items]
Credit facility, maximum borrowing capacity										51,600,000
Letters of credit outstanding										$ 40,300,000
Non-Recourse First Mortgages | Secured Debt
Line of Credit Facility [Line Items]
Number of communities securing debt | community		27	16	18	1	7	14	5	14
Non-Recourse Supplemental Loan | First Mortgage Financing
Line of Credit Facility [Line Items]
Debt face amount		$ 220,500,000	$ 266,900,000	$ 149,300,000	$ 30,000,000.0	$ 29,200,000	$ 238,200,000	$ 160,300,000	$ 111,100,000