Fair Value Measurements - Narrative (Details) - Level 2 - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Market Approach Valuation Technique | Junior subordinated notes
Financial Instruments Not Measured at Fair Value
Market interest rate (as a percent)	4.19%	4.22%
Market Approach Valuation Technique | Mortgages payable | Minimum
Financial Instruments Not Measured at Fair Value
Market interest rate (as a percent)	3.43%	2.87%
Market Approach Valuation Technique | Mortgages payable | Maximum
Financial Instruments Not Measured at Fair Value
Market interest rate (as a percent)	4.09%	3.28%
Carrying and Fair Value | Junior subordinated notes
Financial Instruments Not Measured at Fair Value
Estimated fair value (lower) higher than carrying value	$ 8,596	$ 8,670
Carrying and Fair Value | Mortgages payable
Financial Instruments Not Measured at Fair Value
Estimated fair value (lower) higher than carrying value	$ 265	$ 3,831