2.4.0.84120 - Disclosure - ACQUISITIONS (Details)truefalseIn Thousands, unless otherwise specifiedfalse1false USDfalsefalse$D2013Q1_BranchLocatedInShelbyvilleKentuckyMemberhttp://www.sec.gov/CIK0000720002duration2013-01-01T00:00:002013-03-31T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false falsefalseD2013Q2YTD_BranchLocatedInShelbyvilleKentuckyMemberhttp://www.sec.gov/CIK0000720002duration2013-01-01T00:00:002013-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso421703false USDfalsefalse$I2012_BranchLocatedInShelbyvilleKentuckyMemberhttp://www.sec.gov/CIK0000720002instant2012-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1false 0truefalsetruefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse1false USDtruefalse$D2013Q1_BranchLocatedInShelbyvilleKentuckyMemberhttp://www.sec.gov/CIK0000720002duration2013-01-01T00:00:002013-03-31T00:00:00falsefalseBranch located in Shelbyville, Kentuckyus-gaap_BusinessAcquisitionAxisxbrldihttp://xbrl.org/2006/xbrldimsfg_BranchLocatedInShelbyvilleKentuckyMemberus-gaap_BusinessAcquisitionAxisexplicitMemberUSDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$nanafalse0Branch located in Shelbyville, Kentucky2true 3us-gaap_BusinessAcquisitionLineItemsus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0ACQUISITIONS3false 4msfg_BusinessAcquisitionPurchasePriceAllocationLoansReceivablemsfg_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse2700000027000USD$falsetruefalsexbrli:monetaryItemTypemonetaryThe amount of acquisition cost of a business combination allocated to loans receivable.No definition available.false2Loans4false 4msfg_BusinessAcquisitionPurchasePriceAllocationDepositsmsfg_falsecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse3700000037000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe amount of acquisition cost of a business combination allocated to deposits.No definition available.false2Deposits5false 4us-gaap_BusinessAcquisitionPurchasePriceAllocationGoodwillAmountus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse10000001000USD$falsefalsefalsexbrli:monetaryItemTypemonetaryAmount of goodwill arising from a business combination, which is the excess of the cost of the acquired entity over the amounts assigned to assets acquired and liabilities assumed.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 52 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 53 -Subparagraph d -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Goodwill6false 4us-gaap_BusinessAcquisitionPurchasePriceAllocationAmortizableIntangibleAssetsus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse200000200USD$falsefalsefalsexbrli:monetaryItemTypemonetaryThe amount of acquisition cost of a business combination allocated to an identifiable intangible asset that will be amortized.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 51 -Subparagraph e -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 141 -Paragraph 52 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Intangible asset7false 4us-gaap_GoodwillPurchaseAccountingAdjustmentsus-gaap_truedebitdurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse432000432USD$falsetruefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryPurchase accounting adjustments needed to revise the carrying amount of goodwill to fair value.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 142 -Paragraph 45 -Subparagraph e -Clause 7 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. false2Additional goodwill8false 4msfg_AmortizationPeriodForTimeDepositmsfg_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse004 yearsfalsefalsefalse3falsefalsefalse00falsefalsefalsexbrli:durationItemTypenaRepresents the period of amortization for time deposits.No definition available.false0Amortization period for time deposit premiumfalseACQUISITIONS (Details) (Branch located in Shelbyville, Kentucky, USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.mainsourcefinancial.com/role/DisclosureAcquisitionsDetails38