Revenues - Summary of Amount Receivable from Customers under Various Fee Agreement (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2018	$ 20,076
Balance as of December 31, 2019	19,231
Revenue from Contract with Customers Under Various Fee Agreements [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2018	2,075
Balance as of December 31, 2019	2,413
Increase (decrease)	338
Revenue from Contract with Customers Under Various Fee Agreements [Member] | Property Management Fees [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2018	567
Balance as of December 31, 2019	752
Increase (decrease)	185
Revenue from Contract with Customers Under Various Fee Agreements [Member] | Asset Management Fees [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2018	954
Balance as of December 31, 2019	1,653
Increase (decrease)	699
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, 2018	490
Increase (decrease)	(490)
Revenue from Contract with Customers Under Various Fee Agreements [Member] | Other Fee Income [Member]
Disaggregation Of Revenue [Line Items]
Balance as of December 31, 2018	64
Balance as of December 31, 2019	8
Increase (decrease)	$ (56)