XML 66 R50.htm IDEA: XBRL DOCUMENT
v3.21.1

Servicing Assets - Residential Mortgage Loans (Details) - USD ($) | 3 Months Ended |
--- | --- | ---
Mar. 31, 2021 | Mar. 31, 2020 | Dec. 31, 2020
Servicing Asset at Amortized Cost, Balance [Roll Forward] |  |  |
Balance at beginning of the period | $ 5,617,000 |  |
Balance at end of the period | 8,278,000 |  |
Mortgage Servicing Rights |  |  |
Servicing Assets at Fair Value [Line Items] |  |  |
Loans serviced | 690,900,000 |  | $ 506,000,000.0
Servicing fee income | 358,000 | $ 183,000 |
Servicing Asset at Amortized Cost, Balance [Roll Forward] |  |  |
Balance at beginning of the period | 4,647,000 | 446,000 |
Servicing rights capitalized | 2,342,000 | 184,000 |
Amortization of servicing rights | (199,000) | (33,000) |
Change in valuation allowance | 328,000 | (174,000) |
Balance at end of the period | 7,118,000 | 423,000 |
Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward] |  |  |
Valuation allowance, beginning of period | 435,000 | 98,000 |
Impairment |  | (174,000) |
Recovery | 328,000 |  |
Valuation allowance, end of the period | $ 107,000 | $ 272,000 |

X
- Definition Amount of contractually specified servicing fee, late fee, and ancillary fee recognized as income for servicing asset and servicing liability. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122596-111746 + Details
Name: | us-gaap_ContractuallySpecifiedServicingFeesLateFeesAndAncillaryFeesEarnedInExchangeForServicingFinancialAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition This is the sum of principal amount outstanding for both securitized and unsecuritized loans of all types. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121570589&loc=d3e107314-111719 + Details
Name: | us-gaap_PrincipalAmountOutstandingOnLoansManagedAndSecuritized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amortized amount of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 4 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122492-111745 Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 45 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6469459&loc=d3e122501-111745 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of additions from purchases, assumption or transfer to contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 4 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValueAdditions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of amortization of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 4 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValueAmortization1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_ServicingAssetAtAmortizedValueBalanceRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase (decrease) in the amortized amount from a decrease (increase) in the valuation allowance applied to the servicing asset for a contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 4 -Subparagraph (a)(5) -URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746 + Details
Name: | us-gaap_ServicingAssetAtAmortizedValueValuationAllowance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ServicingAssetsAtFairValueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of decrease in the valuation allowance for impairment of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer from write-downs charged against the allowance. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 4 -Subparagraph (e)(3) -URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746 + Details
Name: | us-gaap_ValuationAllowanceForImpairmentOfRecognizedServicingAssetsAggregateWriteDowns
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Reflects the estimated amount of impairment as of the balance sheet date of recognized servicing assets that are being amortized in proportion to and over the period of estimated net servicing income or loss. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 4 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746 + Details
Name: | us-gaap_ValuationAllowanceForImpairmentOfRecognizedServicingAssetsBalance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of decrease in the valuation allowance for impairment of contract to service financial assets under which the benefits of servicing are expected to more than adequately compensate the servicer from recoveries recognized. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 50 -Section 50 -Paragraph 4 -Subparagraph (e)(2) -URI http://asc.fasb.org/extlink&oid=116651436&loc=d3e122739-111746 + Details
Name: | us-gaap_ValuationAllowanceForImpairmentOfRecognizedServicingAssetsRecoveries
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_ValuationAllowanceForImpairmentOfRecognizedServicingAssetsRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=mrbk_MortgageServicingRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |