Interim Financial Statements (Details)	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Feb. 09, 2020 $ / shares Rate	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Number of urban and suburban shopping centers in the Company's owned portfolio	24
Number of states in which Company operates	11
Simon Property Group, Inc. transaction costs	$ 6,385,000
Operating Leases, Future Minimum Payments Receivable, Current	339,089,000
Operating Leases, Future Minimum Payments Receivable, in Two Years	414,455,000
Operating Leases, Future Minimum Payments Receivable, in Three Years	367,229,000
Operating Leases, Future Minimum Payments Receivable, in Four Years	333,914,000
Operating Leases, Future Minimum Payments Receivable, in Five Years	309,713,000
Operating Leases, Future Minimum Payments Receivable, Thereafter	832,715,000
Shopping Center and Other Operational Revenues	12,018,000	$ 11,562,000
Management Leasing And Development Services	566,000	1,216,000
Total revenue from contracts with customers	12,584,000	12,778,000
Restructuring Charges	362,000	625,000
Costs Associated With Shareowner Activism	$ 0	4,000,000
Substantial Doubt about Going Concern, Management's Evaluation	When preparing financial statements for each annual and interim reporting period, management has the responsibility to evaluate whether there are conditions or events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date that the financial statements are issued. No such conditions or events were identified as of the issuance date of the financial statements contained in this Quarterly Report on Form 10-Q.
Westfarms [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage (in hundredths)	79.00%			79.00%
International Plaza [Member]
Schedule of Equity Method Investments [Line Items]
Ownership percentage (in hundredths)	50.10%			50.10%
Accounting Standards Update 2016-02 [Member]
Schedule of Equity Method Investments [Line Items]
Cumulative Effect New Accounting Principle In Period Of Adoption		3,200,000
Noncontrolling Interest [Member] | Accounting Standards Update 2016-02 [Member]
Schedule of Equity Method Investments [Line Items]
Cumulative Effect New Accounting Principle In Period Of Adoption		$ 1,800,000
Taubman Centers Inc. [Member]
Schedule of Equity Method Investments [Line Items]
Business Acquisition, Ownership Percentage, Simon Operating Partnership | Rate			100.00%
Business Acquisition, Share Price | $ / shares			$ 52.50
TRG [Member]
Schedule of Equity Method Investments [Line Items]
Business Acquisition, Ownership Percentage, Simon Operating Partnership | Rate			80.00%
Business Acquisition, Ownership Percentage, Taubman Family | Rate			20.00%
Line of Credit [Member]
Schedule of Equity Method Investments [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,100,000,000