Loans Receivable - Components of the net investment in leases (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loans Receivable
Minimum lease payments receivable	$ 1,228	$ 1,420
Unearned lease income	(69)	(85)
Total	$ 1,159	$ 1,335

The difference for a finance lease between the gross investment in the lease, and the net investment in the lease.

No definition available.

Name:	mrbk_UnearnedLeaseIncome
Namespace Prefix:	mrbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of minimum lease payments to be received by the lessor for capital leases.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=84165051&loc=d3e45377-112738

+ Details

Name:	us-gaap_CapitalLeasesFutureMinimumPaymentsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The lessor's asset under sales type and direct financing leases. The net investment in direct financing and sales-type leases as of the balance sheet date consisting of: (a) minimum lease payments due on direct financing leases, (b) unguaranteed residual value, and (c) any unamortized initial direct costs on direct financing leases; less: (i) estimated executory costs, (ii) unearned income, and (iii) the accumulated allowance for uncollectible minimum lease payments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=84165051&loc=d3e45377-112738

+ Details

Name:	us-gaap_CapitalLeasesNetInvestmentInDirectFinancingAndSalesTypeLeases
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

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