Mortgages Payable - Summary of Mortgages Payable (Details) - Mortgages Payable $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) mortgage property	Dec. 31, 2018 USD ($) mortgage property
Debt
Number of properties | property	92	60
Weighted Average Stated Interest Rate (as a percent)	4.90%	5.10%
Weighted Average Effective Interest Rate (as a percent)	4.60%	4.60%
Weighted Average Remaining Years Until Maturity	3 years 1 month 6 days	3 years 2 months 12 days
Remaining Principal Balance	$ 408,419	$ 298,377
Unamortized Premium and Deferred Finance Costs Balance, net	1,700	4,192
Net payable amount	$ 410,119	$ 302,569
Number of mortgages | mortgage	27	26
Minimum
Debt
Weighted Average Effective Interest Rate (as a percent)	3.80%	1.10%
Stated interest rate (as a percent)	3.80%	3.80%
Maximum
Debt
Weighted Average Effective Interest Rate (as a percent)	7.60%	7.70%
Stated interest rate (as a percent)	6.90%	6.90%
Variable rate mortgages
Debt
Number of properties | property	1	2
Remaining Principal Balance	$ 7,100	$ 23,300
Number of mortgages | mortgage	1	2
Variable rate mortgages after interest rate arrangements
Debt
Remaining Principal Balance		$ 16,000