Name:	msfg_FinancingReceivableModificationsAdditionalDisclosuresAbstract
Namespace Prefix:	msfg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Represents the period of modifications involving an extension of the maturity date at a stated rate of interest lower than the current market rate for new debt with similar risk.

No definition available.

Name:	msfg_FinancingReceivableModificationsInvolvingExtensionOfMaturityDatePeriod
Namespace Prefix:	msfg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the period of modifications involving a reduction of the stated interest rate of the loan.

No definition available.

Name:	msfg_FinancingReceivableModificationsInvolvingReductionOfStatedInterestRatePeriod
Namespace Prefix:	msfg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

The number of financing receivables that have been modified during the period by troubled debt restructurings.

No definition available.

Name:	msfg_FinancingReceivableModificationsNumberOfLoans
Namespace Prefix:	msfg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

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

No definition available.

Name:	msfg_FinancingReceivableModificationsOtherThanTroubledDebtRestructuringsRecordedInvestment
Namespace Prefix:	msfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of additional commitments to lend to customers whose investments in financing receivables are modified by troubled debt restructurings.

No definition available.

Name:	msfg_FinancingReceivableModificationsPostModificationAdditionalRecordedInvestment
Namespace Prefix:	msfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Represents the amount of specific reserves allocated to customers whose investments in financing receivables are modified by troubled debt restructurings.

No definition available.

Name:	msfg_FinancingReceivableModificationsPostModificationAllocatedSpecificReserves
Namespace Prefix:	msfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Number of financing receivables that have been modified by troubled debt restructurings for which there was a payment default within twelve months following the modification during the period.

No definition available.

Name:	msfg_FinancingReceivableModificationsSubsequentPaymentDefaultNumberOfLoans
Namespace Prefix:	msfg_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

Amount of outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings for which there was a payment default within twelve months following the modification during the period.

No definition available.

Name:	msfg_FinancingReceivableModificationsSubsequentPaymentDefaultRecordedInvestment
Namespace Prefix:	msfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

Name:	msfg_FinancingReceivableModificationsWithinPreviousTwelveMonthsSubsequentlyDefaultedDuringCurrentPeriodAbstract
Namespace Prefix:	msfg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

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

No definition available.

Name:	msfg_FinancingReceivablePostModificationRecordedInvestment
Namespace Prefix:	msfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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

No definition available.

Name:	msfg_FinancingReceivablePreModificationRecordedInvestment
Namespace Prefix:	msfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Represents the period of contractually past due loans, to be considered as payment default under the modified terms.

No definition available.

Name:	msfg_FinancingReceivablesPeriodOfModifiedContractuallyPastDueLoansToBeConsideredAsPaymentDefault
Namespace Prefix:	msfg_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

Represents the increase in allowance for loan losses due to troubled debt restructurings during the period.

No definition available.

Name:	msfg_FinancingReceivablesTroubledDebtRestructuringIncreaseInAllowanceForLoanLosses
Namespace Prefix:	msfg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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.

No definition available.

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

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

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=25495931&loc=d3e18845-111554

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

Reflects the amount of the write-down related to a troubled debt restructuring.

Name:	us-gaap_FinancingReceivablesImpairedTroubledDebtRestructuringWriteDown
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

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

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

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

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=msfg_Family1To4Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis=msfg_DirectMember
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: