Income Tax (Components of Deferred Assets) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets
Unrealized loss on securities available for sale		$ 1,762
Allowance for loan losses	5,344	5,439
Deferred compensation	3,191	2,970
Business tax and AMT credit carryovers	5,463	7,140
Capital loss carryover	144	548
Net operating loss carryover	2,148	2,684
Goodwill impairment	2,611mfsf_DeferredTaxAssetsImpairmentLosses	3,032mfsf_DeferredTaxAssetsImpairmentLosses
Purchase accounting adjustments	1,120	1,161
Other	1,306us-gaap_DeferredTaxAssetsOther	920us-gaap_DeferredTaxAssetsOther
Total assets	21,327us-gaap_DeferredTaxAssetsGross	25,656us-gaap_DeferredTaxAssetsGross
Liabilities
Unrealized gain on securities available for sale	(1,375)
Depreciation and amortization	(532)	(833)
FHLB stock	(447)mfsf_DeferredTaxLiabilitiesFHLBStock	(541)mfsf_DeferredTaxLiabilitiesFHLBStock
State income tax	(757)	(1,011)
Loan fees	(245)	(770)
Investments in limited partnerships	(2,584)	(2,596)
Mortgage servicing rights	(501)	(732)
Other	(361)us-gaap_DeferredTaxLiabilitiesOther	(336)us-gaap_DeferredTaxLiabilitiesOther
Total liabilities	(6,802)us-gaap_DeferredIncomeTaxLiabilities	(6,819)us-gaap_DeferredIncomeTaxLiabilities
Valuation Allowance
Beginning balance	(1,835)		(1,835)
Decrease during period	615
Ending balance	(1,220)		(1,835)
Net deferred tax asset	$ 13,305us-gaap_DeferredTaxAssetsLiabilitiesNet	$ 17,002us-gaap_DeferredTaxAssetsLiabilitiesNet

Deferred tax asset, purchase accounting adjustments.

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Deferred Tax Assets Tax Credit Carry Forwards General Business And Alternative Minimum Tax

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Deferred Tax Liabilities, Depreciation and Amortization

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Deferred Tax Liabilities, FHLB Stock

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Deferred Tax Liabilities, State Income Taxes

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Deferred tax liabilities, unrealized gain on available for sale securities.

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Deferred Tax Liability Deferred Loan Fees

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Amount of deferred tax liability attributable to taxable temporary differences.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from compensation and benefits costs.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from unrealized losses on available-for-sale securities.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences from investments (excludes investments in subsidiaries and equity method investments).

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Amount of deferred tax liability attributable to taxable temporary differences from mortgage servicing rights.

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Amount of deferred tax liability attributable to taxable temporary differences not separately disclosed.

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The amount of the change in the period in the valuation allowance for a specified deferred tax asset.

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