Organization and Significant Accounting Policies - Schedule of Variable Interest Entities (Details) $ in Thousands	Sep. 30, 2020 USD ($) retail_shopping_center	Dec. 31, 2019 USD ($)
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 10,986,639	$ 11,132,253
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	4,873,516	4,842,292
Noncontrolling Interest in Variable Interest Entity	28,827	30,655
Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Liabilities	7,329	17,740
Real Estate [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	129,881	325,464
Cash and Cash Equivalents [Member] | Variable Interest Entity, Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Variable Interest Entity, Consolidated, Carrying Amount, Assets	$ 5,456	$ 57,269
Partially Owned Properties [Member]
Variable Interest Entity [Line Items]
Number of real estate properties | retail_shopping_center	125
Consolidated Properties [Member]
Variable Interest Entity [Line Items]
Number of real estate properties | retail_shopping_center	10