Mortgages Payable - Summary of Mortgages Payable (Details) - Mortgages Payable $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020 USD ($) mortgage property	Dec. 31, 2019 USD ($) mortgage property
Debt
Number of Properties | property	92	92
Weighted Average Stated Interest Rate (as a percent)	4.90%	4.90%
Weighted Average Effective Interest Rate (as a percent)	4.70%	4.60%
Weighted Average Remaining Years Until Maturity	2 years 10 months 24 days	3 years 1 month 6 days
Remaining Principal Balance	$ 406,746	$ 408,419
Unamortized Premium and Deferred Finance Costs Balance, net	1,412	1,700
Net payable amount	$ 408,158	$ 410,119
Debt Instrument Number | mortgage	27	27
Minimum
Debt
Weighted Average Effective Interest Rate (as a percent)	3.80%	3.80%
Debt Instrument, Interest Rate, Stated Percentage	3.80%	3.80%
Maximum
Debt
Weighted Average Effective Interest Rate (as a percent)	7.60%	7.60%
Debt Instrument, Interest Rate, Stated Percentage	6.90%	6.90%
Variable Rate Mortgages [Member]
Debt
Number of Properties | property	1	1
Remaining Principal Balance	$ 7,000	$ 7,100
Debt Instrument Number | mortgage	1	1