Organization and Significant Accounting Policies - Schedule of Variable Interest Entities (Details) $ in Thousands	Mar. 31, 2021 USD ($) retail_shopping_center	Dec. 31, 2020 USD ($)
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 10,625,988	$ 10,936,904
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	4,582,944	4,878,757
Noncontrolling Interest in Variable Interest Entity	28,534	28,685
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	6,349	6,340
Real Estate [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	127,513	127,240
Cash and Cash Equivalents [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 4,793	$ 4,496
Partially Owned Properties [Member]
Variable Interest Entity [Line Items]
Number of real estate properties | retail_shopping_center	123
Consolidated Properties [Member]
Variable Interest Entity [Line Items]
Number of real estate properties | retail_shopping_center	10