-- None. No documentation exists for this element. --

No definition available.

Name:	srce_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract
Namespace Prefix:	srce_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the threshold period of time used to determine if a modified loan is in default or transferred to nonaccrual.

+ References

No definition available.

+ Details

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

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953676-111524

+ Details

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

- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 40
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=82895541&loc=d3e18845-111554

+ Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953682-111524

+ Details

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

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_PerformingFinancingReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InternalCreditAssessmentAxis=us-gaap_NonperformingFinancingReceivableMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_InterestRateBelowMarketReductionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loan and Lease Financings (Details 5) $ in Thousands	3 Months Ended		9 Months Ended
Loan and Lease Financings (Details 5) $ in Thousands	Sep. 30, 2017 USD ($) item	Sep. 30, 2016 item	Sep. 30, 2017 USD ($) item modification	Sep. 30, 2016 item modification	Dec. 31, 2016 USD ($)
Loans and leases classified as TDR
Number of Modifications \| item	0	1	1	1
Number of Defaults \| item	0	0	1	0
Loans and leases classified as troubled debt restructuring	$ 970		$ 970		$ 2,002
Troubled debt restructured loans and leases which had payment defaults within twelve months following modification
Default threshold			90 days
Performing
Loans and leases classified as TDR
Loans and leases classified as troubled debt restructuring	353		$ 353		360
Nonperforming
Loans and leases classified as TDR
Loans and leases classified as troubled debt restructuring	$ 617		$ 617		$ 1,642
Interest Rate Below Market Reduction
Loans and leases classified as TDR
Number of Modifications \| modification			1	1