XML 68 R55.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands | 6 Months Ended |
--- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017
Income Tax Contingency [Line Items] |  |  |
Gross liability for unrecognized tax benefits, exclusive of interest and penalties | $ 15,167 |  | $ 14,480
Unrecognized tax benefits that would affect effective tax rate | 14,546 |  | 13,737
Interest and penalties on unrecognized benefits | 1,379 |  | $ 1,175
Estimated one-time transition tax | 11,544 |  |
Payment of transition tax | 1,000 | $ 0 |
Estimated one-time transition tax, current | 915 |  |
Estimated one-time transition tax, noncurrent | 9,629 |  |
Settlement and Lapse of Statute |  |  |
Income Tax Contingency [Line Items] |  |  |
Unrecognized tax benefits within the next twelve months | $ 2,944 |  |

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 Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Liability + References No definition available. + Details
Name: | seic_TaxCutsAndJobsActof2017IncompleteAccountingTransitionTaxForAccumulatedForeignEarningsProvisionalLiability
Namespace Prefix: | seic_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Liability, Current + References No definition available. + Details
Name: | seic_TaxCutsAndJobsActof2017IncompleteAccountingTransitionTaxForAccumulatedForeignEarningsProvisionalLiabilityCurrent
Namespace Prefix: | seic_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Liability, Noncurrent + References No definition available. + Details
Name: | seic_TaxCutsAndJobsActof2017IncompleteAccountingTransitionTaxForAccumulatedForeignEarningsProvisionalLiabilityNoncurrent
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 increase (decrease) during the period in the amount due for taxes based on the reporting entity's earnings or attributable to the entity's income earning process (business presence) within a given jurisdiction. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
Name: | us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
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 -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32718-109319 + 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://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 15A -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=SL6600010-109319 + 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: |