Impact of COVID-19 - Narrative (Details) $ in Thousands	3 Months Ended			4 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($)	Jun. 30, 2020	Sep. 30, 2019 USD ($)	Oct. 31, 2020	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)
Subsequent Event [Line Items]
Rental revenue	$ 55,749		$ 55,487		$ 163,167	$ 168,242
Rent deferral period	3 months	3 months
Subsequent Event
Subsequent Event [Line Items]
Deferred Rent, Percent Due				0.03
Contractual Base Rent, Operating Expense And Real Estate Recoveries Collected | Revenue
Subsequent Event [Line Items]
Percentage of total revenue	91.00%	83.00%
Operating lease income subject to deferral agreements | Outstanding Billings | Revenue
Subsequent Event [Line Items]
Percentage of total revenue	2.00%	11.00%
Operating lease income subject to deferral agreements | April, May, June 2020 unpaid balance as percent of total unpaid balance | Revenue
Subsequent Event [Line Items]
Percentage of total revenue	24.00%	67.00%
Operating lease income subject to deferral agreements, anchor or national tenants | Outstanding Billings | Revenue
Subsequent Event [Line Items]
Percentage of total revenue	1.00%	4.00%
Retail Real Estate | Contractual Base Rent, Operating Expense And Real Estate Recoveries Collected | Revenue
Subsequent Event [Line Items]
Percentage of total revenue	89.00%	79.00%
Office Real Estate | Contractual Base Rent, Operating Expense And Real Estate Recoveries Collected | Revenue
Subsequent Event [Line Items]
Percentage of total revenue	95.00%	95.00%
Residential Real Estate | Contractual Base Rent, Operating Expense And Real Estate Recoveries Collected | Revenue
Subsequent Event [Line Items]
Percentage of total revenue	100.00%	100.00%