Summary of Significant Accounting Policies - AOCI, Simon Property Group, Inc. (Details) $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($)
Changes in accumulated other comprehensive income (loss)
Beginning balance	$ 3,686,168
Ending balance	3,505,906
Accumulated Other Comprehensive Income (Loss)
Changes in accumulated other comprehensive income (loss)
Beginning balance	(110,453)
Other comprehensive income (loss) before reclassifications	5,835
Amounts reclassified from accumulated other comprehensive income (loss)	1,871
Net current-period other comprehensive income (loss)	7,706
Ending balance	(102,747)
Currency translation adjustments
Changes in accumulated other comprehensive income (loss)
Beginning balance	(118,138)
Other comprehensive income (loss) before reclassifications	11,429
Net current-period other comprehensive income (loss)	11,429
Ending balance	(106,709)
Accumulated derivative gains (losses), net
Changes in accumulated other comprehensive income (loss)
Beginning balance	8,055
Other comprehensive income (loss) before reclassifications	(5,343)
Amounts reclassified from accumulated other comprehensive income (loss)	1,871
Net current-period other comprehensive income (loss)	(3,472)
Ending balance	4,583
Net unrealized losses on marketable securities
Changes in accumulated other comprehensive income (loss)
Beginning balance	(370)
Other comprehensive income (loss) before reclassifications	(251)
Net current-period other comprehensive income (loss)	(251)
Ending balance	$ (621)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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Amount after tax, before reclassification adjustments, of other comprehensive income (loss), attributable to parent.

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount after tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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