Represents the number of branch offices of the entity, whose closure was approved by the board of directors.

No definition available.

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

- Definition

Represents the amount of deposits of branch offices closed by the entity.

+ References

No definition available.

+ Details

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

- Definition

Represents the amount of deposits of branch offices being closed by the entity.

+ References

No definition available.

+ Details

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

- Definition

Represents the total number of branches being closed.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of branch offices which are to be closed located in Frankfort, Kentucky.

+ References

No definition available.

+ Details

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

- Definition

Represents the number of branch offices operated by the entity at specified location.

+ References

No definition available.

+ Details

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

- Definition

Charges against earnings in the period for known and estimated costs of termination benefits provided to current employees that are involuntarily terminated under a benefit arrangement associated with exit from or disposal of business activities or restructurings pursuant to a duly authorized plan, excluding costs or losses pertaining to an entity newly acquired in a business combination or a discontinued operation as defined by generally accepted accounting principles and costs associated with one-time termination benefits.

+ References

No definition available.

+ Details

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

- Details

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

- Definition

The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

+ References

+ Details

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

- Definition

Amount of other expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses associated with a discontinued operation or an asset retirement obligation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6394359&loc=d3e17939-110869

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 5.P.4(b))

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140904-122747

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 420

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.P.3)

-URI http://asc.fasb.org/extlink&oid=27011515&loc=d3e140864-122747

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 5

-Section P

-Subsection 3, 4

+ Details

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

BRANCH CLOSURES (Details) (USD $)	1 Months Ended	3 Months Ended	12 Months Ended
BRANCH CLOSURES (Details) (USD $)	Apr. 30, 2013 item	Jun. 30, 2014 item	Dec. 31, 2014	Dec. 31, 2013 item
BRANCH CLOSURES
Number of branch offices whose closure is approved by the board of directors		3
Number of branch offices to be closed located in Frankfort, Kentucky		1
Deposits of three branch offices to be closed				$ 22,000,000msfg_DepositsOfBranchesToBeClosed
Total number of branches closed	8msfg_NumberOfBranchesClosed
Number of branch offices currently operated in Troy, Ohio				2
Deposits of closed branches				85,000,000msfg_DepositsOfBranchesClosed
Severance costs			25,000msfg_SeveranceExpenses	150,000msfg_SeveranceExpenses
Impairment costs for the affected properties			550,000	550,000
Other costs related to the closing of the branches			$ 25,000us-gaap_OtherRestructuringCosts	$ 50,000us-gaap_OtherRestructuringCosts