Investments in Unconsolidated Entities - Unconsolidated Entity Transactions (Details)					1 Months Ended		3 Months Ended				9 Months Ended
	Sep. 25, 2018 USD ($) shares	Jun. 07, 2018 USD ($)	Sep. 15, 2016 item	Sep. 30, 2015 property	Sep. 30, 2018 USD ($) property	Apr. 30, 2018 USD ($)	Sep. 30, 2018 USD ($) property	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2018 USD ($) property	Sep. 30, 2017 USD ($)	Dec. 31, 2018	Sep. 11, 2018 ft²	Dec. 31, 2017	May 31, 2017
Investment in Unconsolidated Entities
Insurance proceeds recorded as business interruption											$ 16,160,000
Gain upon acquisition of controlling interests, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net											144,949,000	$ 4,989,000
Gain on interest in unconsolidated entities											35,621,000
Share of net income, net of amortization of our excess investment							$ 134,408,000	$ 116,110,000			$ 325,263,000	277,212,000
Outlets at Orange
Investment in Unconsolidated Entities
Percentage of equity stake acquired	50.00%
Ownership interest after acquisition (as a percent)					100.00%		100.00%				100.00%
Simon Property Group, L.P.
Investment in Unconsolidated Entities
Insurance proceeds recorded as business interruption											$ 16,160,000
Gain upon acquisition of controlling interests, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net											144,949,000	4,989,000
Gain on interest in unconsolidated entities											35,621,000
Share of net income, net of amortization of our excess investment							$ 134,408,000	116,110,000			325,263,000	277,212,000
Simon Property Group, L.P. | Outlets at Orange
Investment in Unconsolidated Entities
Number of units issued in connection with acquisition of the remaining interest in orange outlet | shares	475,183
Business acquisition price	$ 176.99
Colorado Mills
Investment in Unconsolidated Entities
Impairment charges									$ 32,500,000
Insurance proceeds recorded as business interruption											58,300,000
Gain on business interruption											$ 25,800,000
Aventura Mall
Investment in Unconsolidated Entities
Loan defeasance charge		$ 30,900,000
Write off of deferred debt issuance cost		6,500,000
Mortgages | Aventura Mall
Investment in Unconsolidated Entities
Debt refinanced		1,200,000,000
Construction loan | Aventura Mall
Investment in Unconsolidated Entities
Debt refinanced		200,800,000
4.12% fixed interest rate mortgage maturing July 2028 | Aventura Mall
Investment in Unconsolidated Entities
Debt issued		$ 1,750,000,000
Fixed interest rate (as a percent)		4.12%
Macerich
Investment in Unconsolidated Entities
Ownership interest (as a percent)					50.00%		50.00%				50.00%
Area of property (in square feet) | ft²														400,000
Additional area of a real estate property | ft²														166,000
Contribution to form joint venture					$ 13,100,000
Aventura Mall
Investment in Unconsolidated Entities
Ownership interest (as a percent)		33.30%
Share of early debt repayment charge		$ 12,500,000
Colorado Mills
Investment in Unconsolidated Entities
Ownership interest (as a percent)																37.50%
Gain upon acquisition of controlling interests, sale or disposal of, or recovery on, assets and interests in unconsolidated entities and impairment, net											$ 9,700,000
Aeropostale
Investment in Unconsolidated Entities
Number of joint ventures | item			2
Aeropostale Retail Operations
Investment in Unconsolidated Entities
Ownership interest (as a percent)					44.95%		44.95%				44.95%
Authentic Brands Group LLC
Investment in Unconsolidated Entities
Ownership interest (as a percent)					5.78%		5.78%				5.78%
Gain on interest in unconsolidated entities						$ 35,600,000
HBS
Investment in Unconsolidated Entities
Ownership interest (as a percent)					11.70%		11.70%				11.70%				11.70%
Number of properties contributed to form joint venture | property					42		42				42
Number of Kaufhof properties purchased by the joint venture | property				41
Contributions for improvements to properties					$ 68,300,000		$ 68,300,000				$ 68,300,000
Contribution to form joint venture										$ 178,500,000
Share of net income, net of amortization of our excess investment							$ 4,300,000	$ 4,800,000			11,900,000	11,300,000
Total revenues											258,800,000	265,800,000
Total operating income											162,200,000	246,900,000
Consolidated net income											$ 90,600,000	$ 176,200,000
HBS | Forecast
Investment in Unconsolidated Entities
Ownership interest (as a percent)													11.70%