Loans (Impaired Loans) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Impaired Financing Receivable With Related Allowance [Abstract]
Recorded balance			$ 676
Unpaid principal balance			676
Specific Allowance	$ 100		100
Average investment in impaired loans			793
Interest income recognized			20
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	6,345	$ 8,392	6,700
Unpaid principal balance, total	6,345	9,200	6,700
Average investment in impaired loans, total	6,523	8,076	7,578
Interest income recognized, total	35	64	225
Commercial Real Estate [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	3,150	5,225	3,608
Unpaid principal balance	3,150	5,225	3,608
Average investment in impaired loans	3,172	5,079	4,115
Interest income recognized	23	56
Impaired Financing Receivable With Related Allowance [Abstract]
Recorded balance	517
Unpaid principal balance	517
Specific Allowance	100		100
Average investment in impaired loans	596
Interest income recognized			172
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	3,667		4,284
Unpaid principal balance, total	3,667		4,284
Average investment in impaired loans, total	3,768		4,908
Interest income recognized, total	23		192
Commercial Segment [Member] \| Construction Loans [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	859	851	595
Unpaid principal balance	859	1,628	595
Average investment in impaired loans	934	891	735
Interest income recognized	12	7
Impaired Financing Receivable With Related Allowance [Abstract]
Interest income recognized			31
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	859		595
Unpaid principal balance, total	859		595
Average investment in impaired loans, total	934		735
Interest income recognized, total	12		31
Commercial Segment [Member] \| Commercial and Industrial [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	208	702	214
Unpaid principal balance	208	733	214
Average investment in impaired loans	212	730	423
Interest income recognized		1
Impaired Financing Receivable With Related Allowance [Abstract]
Interest income recognized			2
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	208		214
Unpaid principal balance, total	208		214
Average investment in impaired loans, total	212		423
Interest income recognized, total			2
Consumer [Member] \| First Mortgage [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	1,126	1,138	1,126
Unpaid principal balance	1,126	1,138	1,126
Average investment in impaired loans	1,126	1,138	1,131
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	1,126		1,126
Unpaid principal balance, total	1,126		1,126
Average investment in impaired loans, total	1,126		1,131
Consumer [Member] \| Second Mortgage [Member]
Impaired Financing Receivable With No Related Allowance [Abstract]
Recorded balance	485	476	481
Unpaid principal balance	485	476	481
Average investment in impaired loans	483	$ 238	381
Impaired Financing Receivables Total [Abstract]
Recorded balance, total	485		481
Unpaid principal balance, total	485		481
Average investment in impaired loans, total	$ 483		$ 381

Impaired Financing Receivable With No Related Allowance [Abstract].

No definition available.

Name:	mfsf_ImpairedFinancingReceivableWithNoRelatedAllowanceAbstract
Namespace Prefix:	mfsf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Impaired Financing Receivable With Related Allowance [Abstract].

+ References

No definition available.

+ Details

Name:	mfsf_ImpairedFinancingReceivableWithRelatedAllowanceAbstract
Namespace Prefix:	mfsf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Impaired Financing Receivables Total [Abstract].

+ References

No definition available.

+ Details

Name:	mfsf_ImpairedFinancingReceivablesTotalAbstract
Namespace Prefix:	mfsf_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5258-111524

+ Details

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

- Definition

Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

+ Details

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

- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 14A
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953550-111524

+ Details

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

- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of average investment of impaired financing receivables for which there is no related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5258-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524

+ Details

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

- Definition

Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of unpaid principal balance of impaired financing receivables for which there is no related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of average investment of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Definition

Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

+ References

+ Details

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

- Definition

Amount of investment in impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Definition

Unpaid principal balance of impaired financing receivables for which there is a related allowance for credit losses.

+ References

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialAndIndustrialSectorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_FirstMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_SecondMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: