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

Represents the additions or transfers to other real estate owned, including, but not limited to, 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. This includes real estate assets taken in settlement of troubled loans through surrender or foreclosure.

No definition available.

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

Represents the roll forward which is a reconciliation of a concept from the beginning of a period to the end of a period.

No definition available.

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

Sales of other real estate owned, including, but not limited to, 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. This includes real estate assets taken in settlement of troubled loans through surrender or foreclosure.

No definition available.

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

Represents the amount of write down of real estate acquired through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement after the initial write down when the real estate is originally placed in other real estate owned.

No definition available.

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

- References

No definition available.

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

- References

No definition available.

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

Amount of expense recognized during the period for the foreclosure on real estate assets.

No definition available.

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

The net gain (loss) resulting from sales and other disposals of other real estate owned, increases (decreases) in the valuation allowance for foreclosed real estate, and write-downs of other real estate owned after acquisition or physical possession.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 225
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.14(d))
-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph 14
-Subparagraph d
-Article 9

Name:	us-gaap_GainsLossesOnSalesOfOtherRealEstate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Reflects the aggregate value of loans, trade receivables, securities and financial instruments that serve as collateral for obligations arising from a transfer of financial assets recorded as a secured borrowing.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5086-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=34720971&loc=SL6224234-111729

Name:	us-gaap_LoansAndLeasesReceivableCollateralForSecuredBorrowings
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.

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

Carrying amount as of the balance sheet date of land and buildings obtained through foreclosure proceedings or defeasance in full or partial satisfaction of a debt arrangement.

Reference 1: 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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 28
-Article 12

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Paragraph c
-Subparagraph Schedule III
-Article 5

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

- References

No definition available.

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

For each period for which an income statement is required, disclosure of the changes in the allowance, including balances at end of period.

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

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 03
-Paragraph 10
-Subparagraph 4
-Article 9

Name:	us-gaap_RealEstateOwnedValuationAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amount of the valuation allowance for real estate owned that was applied in the period against the carrying amount of real estate owned that was sold, written down or written off.

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

Amount of expense recognized in the income statement for a decrease in valuation of real estate owned (REO).