Significant Accounting Policies - AOCI, Simon Property Group L.P. (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	$ 4,954,796
Ending balance	4,724,358
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	11,008
Amounts reclassified from accumulated other comprehensive income	2,275
Net current-period other comprehensive income	13,283
Accumulated Other Comprehensive Income (Loss) | Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	(131,367)
Other comprehensive income (loss) before reclassifications	12,584
Amounts reclassified from accumulated other comprehensive income	2,620
Net current-period other comprehensive income	15,204
Ending balance	(116,163)
Currency translation adjustments, attributable to parent
Changes in accumulated other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	11,530
Net current-period other comprehensive income	11,530
Currency translation adjustments, attributable to parent | Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	(181,706)
Other comprehensive income (loss) before reclassifications	13,148
Net current-period other comprehensive income	13,148
Ending balance	(168,558)
Accumulated derivative gains, attributable to parent
Changes in accumulated other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	(1,110)
Amounts reclassified from accumulated other comprehensive income	2,275
Net current-period other comprehensive income	1,165
Accumulated derivative gains, attributable to parent | Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	34,956
Other comprehensive income (loss) before reclassifications	(1,253)
Amounts reclassified from accumulated other comprehensive income	2,620
Net current-period other comprehensive income	1,367
Ending balance	36,323
Net unrealized gains on sale of marketable securities
Changes in accumulated other comprehensive income (loss)
Other comprehensive income (loss) before reclassifications	588
Net current-period other comprehensive income	588
Net unrealized gains on sale of marketable securities | Simon Property Group L.P.
Changes in accumulated other comprehensive income (loss)
Beginning Balance	15,383
Other comprehensive income (loss) before reclassifications	689
Net current-period other comprehensive income	689
Ending balance	$ 16,072