Fee and Other Income - Summary of Amount Receivable from Customers under Various Fee Agreement (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2019	$ 19,231
Balance as of December 31, 2020	17,502
Revenue from Contract with Customers Under Various Fee Agreements [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2019	2,413
Balance as of December 31, 2020	5,179
Increase	2,766
Revenue from Contract with Customers Under Various Fee Agreements [Member] | Property Management Fees [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2019	752
Balance as of December 31, 2020	793
Increase	41
Revenue from Contract with Customers Under Various Fee Agreements [Member] | Asset Management Fees [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2019	1,653
Balance as of December 31, 2020	1,949
Increase	296
Revenue from Contract with Customers Under Various Fee Agreements [Member] | Acquisition, Disposition and Leasing Fee [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2020	2,259
Increase	2,259
Revenue from Contract with Customers Under Various Fee Agreements [Member] | Other Fee Income [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2019	8
Balance as of December 31, 2020	178
Increase	$ 170