XML 69 R59.htm IDEA: XBRL DOCUMENT
v3.23.3

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands | Sep. 30, 2023 | Dec. 31, 2022
--- | --- | ---
Income Tax Contingency [Line Items] |  |
Gross liability for unrecognized tax benefits, exclusive of interest and penalties | $ 17,618 | $ 15,204
Unrecognized tax benefits that would affect effective tax rate | 17,224 | 14,431
Interest and penalties on unrecognized benefits | 1,916 | $ 1,118
Settlement and Lapse of Statute |  |
Income Tax Contingency [Line Items] |  |
Unrecognized tax benefits within the next twelve months | $ 4,172 |

X
- Definition Gross Liability For Unrecognized Tax Benefits Exclusive Of Interest And Penalties + References No definition available. + Details
Name: | seic_GrossLiabilityForUnrecognizedTaxBenefitsExclusiveOfInterestAndPenalties
Namespace Prefix: | seic_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_IncomeTaxContingencyLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The amount of the unrecognized tax benefit of a position taken for which it is reasonably possible that the total amount thereof will significantly increase or decrease within twelve months of the balance sheet date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15 + Details
Name: | us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleAmountOfUnrecordedBenefit
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15 + Details
Name: | us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 740 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 15A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482685/740-10-50-15A + Details
Name: | us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_ReasonablyPossibleSignificantChangeInUnrecognizedTaxBenefitsByItemAxis=seic_SettlementandLapseofStatuteMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |