XML 93 R61.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Loans and Related Allowance for Loan and Lease Losses (Textual) (Detail) - USD ($) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 | Sep. 30, 2016
Number of Days Past Due | 90 years |  |  |
Financing Receivable, Modifications, Recorded Investment | $ 3,100,000 | $ 2,900,000 |  |
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans | 259,000 | $ 207,000 | $ 439,000 |
Threshold For Loans Evaluated For Impairment [Member] |  |  |  |
Loans and Leases Receivable before Fees, Gross | 1,000,000 |  |  | $ 1,000,000
Threshold For Loans Evaluated For Impairment [Member] | Outside Consultant [Member] |  |  |  |
Loans and Leases Receivable before Fees, Gross | 250,000 |  |  | 250,000
Threshold For Loans Evaluated For Impairment [Member] | Criticized Relationships [Member] |  |  |  |
Financing Receivable, Gross | 125,000 |  |  | $ 125,000
Threshold For Loans Evaluated For Impairement [Member] |  |  |  |
Notes, Loans and Financing Receivable, Gross, Current | 150,000 |  |  |
Real Estate Construction Porfolio Segment [Member] |  |  |  |
Financing Receivable, Allowance for Credit Losses, Write-downs | 400,000 |  |  |
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member] |  |  |  |
Financing Receivable, Allowance for Credit Losses, Write-downs | $ 300,000 |  |  |
Commercial Real Estate Portfolio Segment [Member] |  |  |  |
Financing Receivable, Increase in Portfolio, Percent | 21.50% |  |  |

X
- Definition The percentage increase in the financing receivable portfolio. + References No definition available. + Details
Name: | mbcn_FinancingReceivableIncreaseInPortfolioPercent
Namespace Prefix: | mbcn_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of days past due. + References No definition available. + Details
Name: | mbcn_NumberOfDaysForLoanPastDue
Namespace Prefix: | mbcn_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of direct write-downs of financing receivables charged against the allowance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The amount of the outstanding recorded investment related to 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 40 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Recorded Investment -URI http://asc.fasb.org/extlink&oid=65880944 + Details
Name: | us-gaap_FinancingReceivableModificationsRecordedInvestment
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount, before allowance and fees, of loans and leases receivable. Excludes loans and leases covered under loss sharing agreements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522 + Details
Name: | us-gaap_LoansAndLeasesReceivableBeforeFeesGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Reflects the amount of additional interest income that would have been recorded if impaired or nonperforming loans were instead current, in compliance with their original terms, and outstanding throughout the reporting period or since origination (if held for part of the period). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 40 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18794-111554 + Details
Name: | us-gaap_LoansAndLeasesReceivableImpairedInterestLostOnNonaccrualLoans
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition An amount representing an agreement for an unconditional promise by the maker to pay the Entity (holder) a definite sum of money at a future date(s) within one year of the balance sheet date or the normal operating cycle, whichever is longer. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 45 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4531-111522 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 210.5-02.3(a),(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (c),(e) -URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765 + Details
Name: | us-gaap_NotesAndLoansReceivableGrossCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount representing an agreement for an unconditional promise by the maker to pay the entity (holder) a definite sum of money at a future date. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. Excludes amounts related to receivables held-for-sale. + 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 210.9-03.10(3)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 + Details
Name: | us-gaap_NotesReceivableGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbcn_ThresholdForLoansEvaluatedForImpairmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis=mbcn_OutsideConsultantMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis=mbcn_CriticizedRelationshipsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbcn_ThresholdForLoansEvaluatedForImpairementMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentPerformanceStatusAxis=mbcn_RealEstateConstructionPorfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentPerformanceStatusAxis=mbcn_RealEstateMortgagePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=mbcn_ResidentialLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentPerformanceStatusAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |