Name:	srce_EquityMethodInvestmentOwnershipPercentageMinimum
Namespace Prefix:	srce_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the number of classes that exist within loan and lease portfolio.

No definition available.

Name:	srce_LoanAndLeasePortfolioNumberOfClasses
Namespace Prefix:	srce_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Minimum loan or lease amount necessary for impairment evaluation. An allowance is only created if it is probable that all amounts due will not be collected pursuant to the contractual terms of the loan or lease and the recorded investment in the loan or lease exceeds its fair value.

No definition available.

Name:	srce_LoanAndLeasesImpairmentAmountForCreationOfAllowance
Namespace Prefix:	srce_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Represents the amount of loans and leases where the internal credit quality grade is at or below a predetermined classification which are included in comprehensive analysis.

No definition available.

Name:	srce_LoansAndLeasesReceivableEvaluatedForImpairment
Namespace Prefix:	srce_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the loans available for repurchase under the Government National Mortgage Association optional repurchase programs with the offsetting liability recorded within other short-term borrowings.

No definition available.

Name:	srce_LoansAvailableForRepurchase
Namespace Prefix:	srce_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Number of reportable units used to categorize goodwill allocation.

No definition available.

Name:	srce_NumberOfReportableUnitsUsedForGoodwillAllocation
Namespace Prefix:	srce_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Represents the term of operation leases.

No definition available.

Name:	srce_OperatingLeaseTerm
Namespace Prefix:	srce_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the percentage of the principal balance that may be repurchased of a delinquent Ginnie Mae (GNMA) mortgage loan.

No definition available.

Name:	srce_PercentageOfPrincipalBalanceThatMayBeRepurchasedOfDelinquentMortgageLoan
Namespace Prefix:	srce_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

Represents the term of short-term borrowings.

No definition available.

Name:	srce_ShortTermDebtTerm
Namespace Prefix:	srce_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the period of sustained performance required to change loan from non-performing to performing.

No definition available.

Name:	srce_SustainedPerformancePeriodRequiredForPerformingStatus
Namespace Prefix:	srce_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_ForeclosedAssetsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_GoodwillAndIntangibleAssetsDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Value of the investment at close of period. For investment in and advances to affiliates, if operations of any controlled companies are different in character from those of the company, group such affiliates within divisions and by type of activities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611322-123010

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 14
-Paragraph 2
-Article 12

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 14
-Paragraph 3
-Article 12

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 14
-Paragraph Column E
-Article 12

Name:	us-gaap_InvestmentsInAndAdvancesToAffiliatesAtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

No definition available.

Name:	us-gaap_InvestmentsInAndAdvancesToAffiliatesBalanceAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_LeasesOperatingAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_LoansAndLeasesReceivableDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

No definition available.

Name:	us-gaap_NumberOfReportableSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Carrying amount as of the balance sheet date of assets other than real property that were received in full or partial satisfaction of a debt arrangement through foreclosure proceedings or defeasance.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5162-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4437-111522

Name:	us-gaap_OtherForeclosedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Carrying amount as of the balance sheet date of other real estate and foreclosed assets. Other real estate may include real estate investments, real estate loans that qualify as investments in real estate, and premises that are no longer used in operations may also be included in real estate owned. Foreclosed assets include all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.10(4))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Name:	us-gaap_OtherRealEstateAndForeclosedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

No definition available.

Name:	us-gaap_OtherRealEstateAndForeclosedAssetsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_ProvisionForLoanAndLeaseLossesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_SegmentReportingAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

No definition available.

Name:	us-gaap_ShortTermBorrowingsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=us-gaap_ResidentialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=us-gaap_FederalFundsPurchasedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=srce_OtherShortTermDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_DebtInstrumentAxis=us-gaap_CommercialPaperMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: