Significant Accounting Policies - Rollforward Of Noncontrolling Interest, Simon Group Property L.P. (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Noncontrolling interests:
Net income attributable to noncontrolling nonredeemable interests	$ 72,945	$ 81,459
Distributions to noncontrolling nonredeemable interest holders	(84,221)	(83,728)
Contributions by noncontrolling interests, net, and other	171
Simon Property Group L.P.
Noncontrolling interests:
Noncontrolling nonredeemable interests in properties, beginning of period	5,116	3,456
Net income attributable to noncontrolling nonredeemable interests	675	657
Distributions to noncontrolling nonredeemable interest holders	(1,315)	(654)
Contributions by noncontrolling interests, net, and other	171
Noncontrolling nonredeemable interests in properties, end of period	$ 4,647	$ 3,459