Summary of Significant Accounting Policies - Noncontrolling Interests, Simon Property Group, Inc. (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Summary of Significant Accounting Policies.
Limited partners' interests in the Operating Partnership	$ 644,348	$ 741,449
Nonredeemable noncontrolling interests in properties, net	5,116	3,456
Total noncontrolling interests reflected in equity	$ 649,464	$ 744,905	$ 858,328	$ 973,226