Significant Accounting Policies - Rollforward Of Noncontrolling Interest, Simon Group Property L.P. (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Noncontrolling interests:
Distributions to noncontrolling nonredeemable interest holders			$ (1,842)
Contributions by noncontrolling interests, net, and other			(1,947)
Simon Property Group L.P.
Noncontrolling interests:
Beginning balance			5,216,369
Contributions by noncontrolling interests, net, and other			(1,947)
End balance	$ 5,326,813		5,326,813
Simon Property Group L.P. | Noncontrolling Interests
Noncontrolling interests:
Beginning balance	3,853	$ (411)	3,456	$ (229)
Net income attributable to noncontrolling nonredeemable interests	650	840	1,989	2,138
Distributions to noncontrolling nonredeemable interest holders	(640)	(781)	(1,842)	(2,861)
Contributions by noncontrolling interests, net, and other	421	164	681	764
End balance	$ 4,284	$ (188)	$ 4,284	$ (188)