Organization and Significant Accounting Policies - Organization and Principles of Consolidation (Details) $ in Millions	9 Months Ended
	Sep. 30, 2020 USD ($) retail_shopping_center
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Unsecured public and private notes | $	$ 200
Operating Partnership [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Ownership percentage of outstanding common partnership units	99.60%
COVID-19 [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Percentage of Operating Centers	80.00%
Percentage of Base Rent Collected from Tenants	86.00%
Number of Rent Deferrals	1,300
Wholly Owned Properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of real estate properties	299
Unconsolidated Properties [Member]
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Number of real estate properties	115