Fair Value Measurements (Details)	Mar. 31, 2022 USD ($) item	Dec. 31, 2021 USD ($) item
Fair value measurements
Number of interest rate swaps | item	2
Notional Amount	$ 100,000,000
Mortgage loans receivable, net of loan loss reserve	346,543,000	$ 344,442,000
Notes receivable, net of loan loss reserve	61,508,000	28,337,000
Term loans, net of debt issue cost	762,782,000	722,719,000
Senior unsecured notes, net of debt issue costs	$ 505,482,000	$ 512,456,000
Level 3 | Senior Unsecured Notes maturing before 2030 | Discount Rate
Fair value measurements
Future cash outflows discount rate (as a percent) | item	0.0425	0.0300
Level 3 | Senior Unsecured Notes maturing 2030 and after | Discount Rate
Fair value measurements
Future cash outflows discount rate (as a percent) | item	0.0450	0.0325
Level 3 | Mortgage Loans Receivable | Discount Rate
Fair value measurements
Future cash inflows discount rate (as a percent)	0.094	0.095
Level 3 | Notes Receivable | Discount Rate
Fair value measurements
Future cash inflows discount rate (as a percent) | item	0.064	0.056
Carrying Value
Fair value measurements
Mortgage loans receivable, net of loan loss reserve	$ 346,543,000	$ 344,442,000
Notes receivable, net of loan loss reserve	61,508,000	28,337,000
Revolving line of credit	157,900,000	110,900,000
Term loans, net of debt issue cost	99,400,000	99,363,000
Senior unsecured notes, net of debt issue costs	505,482,000	512,456,000
Fair Value
Fair value measurements
Revolving line of credit	157,900,000	110,900,000
Term loans, net of debt issue cost	100,000,000	100,000,000
Fair Value | Level 3
Fair value measurements
Mortgage loans receivable, net of loan loss reserve	406,669,000	405,162,000
Notes receivable, net of loan loss reserve	66,576,000	28,653,000
Senior unsecured notes, net of debt issue costs	$ 503,887,000	$ 540,045,000