FAIR VALUE (Details)	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012
FAIR VALUE
Number of times a sample of prices supplied by the pricing agent is validated by comparison to prices obtained from other third party sources	2
Servicing Rights
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value
PSA (as a percent)	174.00%	332.00%
Discount rate (as a percent)	10.00%	10.00%
Minimum \| Impaired Loans
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value
Adjustments for differences between the comparable sales and income (as a percent)	0.00%
Minimum \| Other real estate owned
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value
Adjustments for differences between the comparable sales and income (as a percent)	0.00%
Maximum \| Impaired Loans
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value
Adjustments for differences between the comparable sales and income (as a percent)	50.00%
Maximum \| Other real estate owned
Quantitative information about level 3 fair value measurements for financial instruments measured at fair value
Adjustments for differences between the comparable sales and income (as a percent)	50.00%

Represents the number of times a sample of prices supplied by the pricing agent is validated by comparison to prices obtained from other third party sources.

No definition available.

+ Details

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

- Details

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

- Details

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

- Definition

Percentage of adjustment to the observed price for a similar asset or liability when an identical transaction does not exist, used as an input to measure fair value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (bbb)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueInputsComparabilityAdjustments
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

+ References

+ Details

Name:	us-gaap_FairValueInputsDiscountRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Rate at which loans or a loan portfolio are expected to prepay principal balances, used as an input to measure fair value.

+ References

+ Details

Name:	us-gaap_FairValueInputsPrepaymentRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration