Equity - Temporary Equity (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Redeemable preferred stock
Preferred stock stated dividend rate percentage	8.375%	8.375%
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests in properties	$ 201,680	$ 190,480
Simon Property Group, L.P.
Redeemable preferred stock
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests in properties	201,680	190,480
7.5% Cumulative Redeemable Preferred Units
Redeemable preferred stock
Noncontrolling interests redeemable at amounts in excess of fair value	$ 0	$ 0
Preferred stock stated dividend rate percentage	7.50%	7.50%
Temporary equity, shares authorized	260,000	260,000
Temporary equity, shares issued	255,373	255,373
Temporary equity, shares outstanding	255,373	255,373
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests in properties	$ 25,537	$ 25,537
7.5% Cumulative Redeemable Preferred Units | Simon Property Group, L.P.
Redeemable preferred stock
Preferred stock stated dividend rate percentage	7.50%	7.50%
Temporary equity, shares authorized	260,000	260,000
Temporary equity, shares issued	255,373	255,373
Temporary equity, shares outstanding	255,373	255,373
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests in properties	$ 25,537	$ 25,537
Other noncontrolling redeemable interest
Redeemable preferred stock
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests in properties	176,143	164,943
Other noncontrolling redeemable interest | Simon Property Group, L.P.
Redeemable preferred stock
Limited partners' preferred interest in the Operating Partnership and noncontrolling redeemable interests in properties	$ 176,143	$ 164,943