Date the debt instrument was callable after, in CCYY-MM-DD format.

No definition available.

Name:	msl_DebtInstrumentCallableAfterDate
Namespace Prefix:	msl_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of penalty paid for early redemption of debt after tax.

+ References

No definition available.

+ Details

Name:	msl_EarlyRedemptionChargeAfterTax
Namespace Prefix:	msl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Refers to redemption of statutory trust.

+ References

No definition available.

+ Details

Name:	msl_RedemptionOfStatutoryTrust
Namespace Prefix:	msl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(1))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Date the debt instrument was issued, in CCYY-MM-DD format.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentIssuanceDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Details

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

- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22(a)(2))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentMaturityDate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Including the current and noncurrent portions, the carrying value of junior subordinated long-term debt owed to unconsolidated subsidiary trusts as of the balance sheet date. Such debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets and was initially scheduled to be repaid after one year or beyond the normal operating cycle if longer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Details

Name:	us-gaap_ScheduleOfSharesSubjectToMandatoryRedemptionBySettlementTermsAxis=us-gaap_TrustPreferredSecuritiesSubjectToMandatoryRedemptionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

JUNIOR SUBORDINATED DEBENTURES (Details) (USD $)	3 Months Ended	12 Months Ended
JUNIOR SUBORDINATED DEBENTURES (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Debt Issued		$ 22,167,000	$ 29,384,000
Redemption of Statutory Trust I		7,217,000msl_RedemptionOfStatutoryTrust	0msl_RedemptionOfStatutoryTrust	0msl_RedemptionOfStatutoryTrust
Early extinguishment charge, after tax	168,000msl_EarlyRedemptionChargeAfterTax
Trust Preferred Securities Subject to Mandatory Redemption [Member]
Debt Instrument [Line Items]
Debt Issued		22,167,000	29,384,000
Trust Preferred Securities Subject to Mandatory Redemption [Member] \| Junior Subordinated Debt February 22, 2001 issuance [Member]
Debt Instrument [Line Items]
Date Issued		Feb. 22, 2001
Maturity Date		Feb. 22, 2031
Interest Rate (in hundredths)		10.20%
Callable After		Feb. 22, 2011
Debt Issued		0	7,217,000
Trust Preferred Securities Subject to Mandatory Redemption [Member] \| Junior Subordinated Debentures July 31, 2001 issuance [Member]
Debt Instrument [Line Items]
Date Issued		Jul. 31, 2001
Maturity Date		Jul. 09, 2031
Variable Rate Basis		3 month LIBOR
Basis spread on variable rate (in hundredths)		3.30%
Callable After		Jul. 31, 2006
Debt Issued		5,671,000	5,671,000
Trust Preferred Securities Subject to Mandatory Redemption [Member] \| Junior Subordinated Debentures September 20, 2004 issuance [Member]
Debt Instrument [Line Items]
Date Issued		Sep. 20, 2004
Maturity Date		Sep. 20, 2034
Variable Rate Basis		3 month LIBOR
Basis spread on variable rate (in hundredths)		2.50%
Callable After		Sep. 20, 2009
Debt Issued		8,248,000	8,248,000
Trust Preferred Securities Subject to Mandatory Redemption [Member] \| Junior Subordinated Debentures October 12, 2006 issuance [Member]
Debt Instrument [Line Items]
Date Issued		Oct. 12, 2006
Maturity Date		Oct. 12, 2036
Variable Rate Basis		3 month LIBOR
Basis spread on variable rate (in hundredths)		1.85%
Callable After		Jun. 26, 2011
Debt Issued		5,155,000	5,155,000
Trust Preferred Securities Subject to Mandatory Redemption [Member] \| Junior Subordinated Debentures June 21, 2007 issuance [Member]
Debt Instrument [Line Items]
Date Issued		Jun. 21, 2007
Maturity Date		Jun. 21, 2037
Variable Rate Basis		3 month LIBOR
Basis spread on variable rate (in hundredths)		1.70%
Callable After		Jun. 15, 2012
Debt Issued		$ 3,093,000	$ 3,093,000