Loans and Allowance for Credit Losses - Loans - Allowance And Recorded Investment In Financing Receivables (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance	$ 32,588	$ 16,876	$ 18,957	$ 14,597
Charge-offs	(33)	(15)	(357)	(81)
Recoveries	22	69	63	189
Provisions	1,427	1,550	3,074	3,775
Allowance for loan losses, ending balance	34,004	18,480	34,004	18,480
Allowance for loan losses: ending balance, individually evaluated for impairment	1,090	910	1,090	910
Allowance for loan losses: ending balance, collectively evaluated for impairment	32,914	17,570	32,914	17,570
Loans receivable: ending balance, collectively evaluated for impairment	4,132,196	3,322,457	4,132,196	3,322,457
Loans receivable: ending balance, individually evaluated for impairment	13,461	3,697	13,461	3,697
Loans, net of unearned interest	4,145,657	3,314,942	4,145,657	3,314,942	$ 3,514,119
Acquired with credit deterioration
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Loans, net of unearned interest		3,818		3,818
Commercial portfolio \| Commercial real estate
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance	14,197	11,991	13,142	9,415
Charge-offs	0	0	(16)	0
Recoveries	0	63	0	128
Provisions	4,483	468	4,952	2,979
Allowance for loan losses, ending balance	18,680	12,522	18,680	12,522
Allowance for loan losses: ending balance, individually evaluated for impairment	380	28	380	28
Allowance for loan losses: ending balance, collectively evaluated for impairment	18,300	12,494	18,300	12,494
Loans receivable: ending balance, collectively evaluated for impairment	2,281,707	1,944,802	2,281,707	1,944,802
Loans receivable: ending balance, individually evaluated for impairment	6,689	713	6,689	713
Loans, net of unearned interest	2,288,396	1,942,725	2,288,396	1,942,725	2,052,934
Commercial portfolio \| Commercial real estate \| Acquired with credit deterioration
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Loans, net of unearned interest		1,364		1,364	2,537
Commercial portfolio \| Commercial and industrial
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance	11,403	3,671	4,593	3,439
Charge-offs	0	(1)	(220)	(1)
Recoveries	0	0	0	13
Provisions	(4,072)	879	(3,647)	1,098
Allowance for loan losses, ending balance	7,331	4,549	7,331	4,549
Allowance for loan losses: ending balance, individually evaluated for impairment	708	831	708	831
Allowance for loan losses: ending balance, collectively evaluated for impairment	6,623	3,718	6,623	3,718
Loans receivable: ending balance, collectively evaluated for impairment	646,883	556,796	646,883	556,796
Loans receivable: ending balance, individually evaluated for impairment	1,556	1,309	1,556	1,309
Loans, net of unearned interest	648,439	555,487	648,439	555,487	596,042
Commercial portfolio \| Commercial and industrial \| Acquired with credit deterioration
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Loans, net of unearned interest		0		0	0
Commercial portfolio \| Construction
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance	3,667	46	0	38
Charge-offs	0	0	0	0
Recoveries	0	0	0	24
Provisions	2,211	5	2,664	(11)
Allowance for loan losses, ending balance	5,878	51	5,878	51
Allowance for loan losses: ending balance, individually evaluated for impairment	0	0	0	0
Allowance for loan losses: ending balance, collectively evaluated for impairment	5,878	51	5,878	51
Loans receivable: ending balance, collectively evaluated for impairment	459,959	400,188	459,959	400,188
Loans receivable: ending balance, individually evaluated for impairment	2,256	0	2,256	0
Loans, net of unearned interest	462,215	398,966	462,215	398,966	441,246
Commercial portfolio \| Construction \| Acquired with credit deterioration
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Loans, net of unearned interest		1,222		1,222	0
Consumer portfolio \| Residential mortgage
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance	3,145	1,143	1,319	1,019
Charge-offs	0	(3)	(4)	(3)
Recoveries	7	0	37	4
Provisions	(1,060)	162	(826)	282
Allowance for loan losses, ending balance	2,092	1,302	2,092	1,302
Allowance for loan losses: ending balance, individually evaluated for impairment	2	51	2	51
Allowance for loan losses: ending balance, collectively evaluated for impairment	2,090	1,251	2,090	1,251
Loans receivable: ending balance, collectively evaluated for impairment	740,573	412,518	740,573	412,518
Loans receivable: ending balance, individually evaluated for impairment	2,960	1,675	2,960	1,675
Loans, net of unearned interest	743,533	409,611	743,533	409,611	416,221
Consumer portfolio \| Residential mortgage \| Acquired with credit deterioration
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Loans, net of unearned interest		1,232		1,232	1,140
Consumer portfolio \| Consumer
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance	176	2	29	2
Charge-offs	(33)	(11)	(117)	(77)
Recoveries	15	6	26	20
Provisions	(135)	5	(69)	57
Allowance for loan losses, ending balance	23	2	23	2
Allowance for loan losses: ending balance, individually evaluated for impairment	0	0	0	0
Allowance for loan losses: ending balance, collectively evaluated for impairment	23	2	23	2
Loans receivable: ending balance, collectively evaluated for impairment	3,074	8,153	3,074	8,153
Loans receivable: ending balance, individually evaluated for impairment	0	0	0	0
Loans, net of unearned interest	3,074	8,153	3,074	8,153	7,676
Consumer portfolio \| Consumer \| Acquired with credit deterioration
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Loans, net of unearned interest		0		0	$ 0
Unallocated
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Allowance for loan losses, beginning balance		23	(126)	684
Charge-offs		0	0	0
Recoveries		0	0	0
Provisions		31	0	(630)
Allowance for loan losses, ending balance	$ 0	54	$ 0	54
Allowance for loan losses: ending balance, individually evaluated for impairment		0		0
Allowance for loan losses: ending balance, collectively evaluated for impairment		54		54
Loans receivable: ending balance, collectively evaluated for impairment		0		0
Loans receivable: ending balance, individually evaluated for impairment		0		0
Loans, net of unearned interest		0		0
Unallocated \| Acquired with credit deterioration
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss [Roll Forward]
Loans, net of unearned interest		$ 0		$ 0

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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

- Definition

The valuation allowance for financing receivables that are expected to be uncollectible that were collectively evaluated for impairment.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (g)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

+ Details

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

- Definition

Amount of valuation allowance for financing receivables that are expected to be uncollectible that were individually evaluated for impairment.

+ References

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The balance of financing receivables that were collectively evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L(5)(a))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480418/310-10-S99-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11C
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11C

+ Details

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

- Definition

Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (e)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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

- Definition

Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

+ Details

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

- Definition

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-5

+ Details

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

- Definition

Amount, excluding accrued interest, of credit loss expense (reversal of expense) on financing receivable. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

+ Details

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

- Definition

The balance of financing receivables that were individually evaluated for impairment.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 11C
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11C

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 4
-Subparagraph (SAB Topic 6.L(5)(a))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480418/310-10-S99-4

+ Details

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

- Details

Name:	us-gaap_CreditLossStatusAxis=us-gaap_FinancialAssetAcquiredWithCreditDeteriorationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_UnallocatedFinancingReceivablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: