Special dividends declared during the period for each share of common stock outstanding.

No definition available.

Name:	mrbk_CommonStockSpecialDividendsPerShareDeclared
Namespace Prefix:	mrbk_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Special dividends paid during the period for each share of common stock outstanding.

+ References

No definition available.

+ Details

Name:	mrbk_CommonStockSpecialDividendsPerSharePaid
Namespace Prefix:	mrbk_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate dividends paid during the period for each share of common stock outstanding.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

+ Details

Name:	us-gaap_CommonStockDividendsPerShareCashPaid
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of paid and unpaid common stock dividends declared with the form of settlement in cash.

+ References

+ Details

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

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

- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

+ Details

Name:	us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended
	Apr. 22, 2021	Feb. 16, 2021	Jan. 28, 2021	Mar. 31, 2021	Apr. 26, 2021	Dec. 31, 2020
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Cash dividend declared per common share			$ 0.125
Cash dividends paid				$ 0.125
Total dividends				$ 6,931
Common Stock, Special Dividends, Per Share, Declared		$ 1.00
Common stock special dividend paid				$ 1.00
Common Stock, Par or Stated Value Per Share				$ 1		$ 1
Subsequent event
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Cash dividend declared per common share	$ 0.125
Stock Repurchase Program, Authorized Amount					$ 6,000
Common Stock, Par or Stated Value Per Share					$ 1.00