Loans, Net Loans modified in TDR by class of loan (Details) $ in Thousands	12 Months Ended
Dec. 31, 2015 USD ($) loan	Dec. 31, 2014 USD ($) loan
Loans modified in a TDR by class of loan [Abstract]
Number of Contracts \| loan	7	5
Pre-Modification Outstanding Recorded Investment	$ 15,236	$ 1,390
Post-Modification Outstanding Recorded Investment	$ 14,821	$ 1,390
Real Estate Loans Construction [Member]
Loans modified in a TDR by class of loan [Abstract]
Number of Contracts \| loan	0	0
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0
Post-Modification Outstanding Recorded Investment	$ 0	$ 0
Real Estate Loans Secured by Farmland [Member]
Loans modified in a TDR by class of loan [Abstract]
Number of Contracts \| loan	1	0
Pre-Modification Outstanding Recorded Investment	$ 7,903	$ 0
Post-Modification Outstanding Recorded Investment	$ 7,903	$ 0
Real Estate Loans Secured by 1 - 4 Family Residential [Member]
Loans modified in a TDR by class of loan [Abstract]
Number of Contracts \| loan	0	4
Pre-Modification Outstanding Recorded Investment	$ 0	$ 1,190
Post-Modification Outstanding Recorded Investment	$ 0	$ 1,190
Other Real Estate Loans [Member]
Loans modified in a TDR by class of loan [Abstract]
Number of Contracts \| loan	4	1
Pre-Modification Outstanding Recorded Investment	$ 4,283	$ 200
Post-Modification Outstanding Recorded Investment	$ 3,872	$ 200
Real Estate Loans [Member]
Loans modified in a TDR by class of loan [Abstract]
Number of Contracts \| loan	5	5
Pre-Modification Outstanding Recorded Investment	$ 12,186	$ 1,390
Post-Modification Outstanding Recorded Investment	$ 11,775	$ 1,390
Commercial Loans [Member]
Loans modified in a TDR by class of loan [Abstract]
Number of Contracts \| loan	1	0
Pre-Modification Outstanding Recorded Investment	$ 50	$ 0
Post-Modification Outstanding Recorded Investment	$ 46	$ 0
Consumer Loans [Member]
Loans modified in a TDR by class of loan [Abstract]
Number of Contracts \| loan	1	0
Pre-Modification Outstanding Recorded Investment	$ 3,000	$ 0
Post-Modification Outstanding Recorded Investment	$ 3,000	$ 0

-- None. No documentation exists for this element. --

No definition available.

Name:	mbrg_LoansModifiedInTdrByClassOfLoanAbstract
Namespace Prefix:	mbrg_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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

- Details

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