Loans, Allowance for Credit Losses and Impaired Loans - Aging (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Past due financing receivables
Total Financing Receivables	$ 1,169,466	$ 1,117,195
Nonaccrual loans	4,574	8,961
Unamortized discounts on acquired loans	1,900	2,300
Current
Past due financing receivables
Current Balance	1,163,325	1,112,120
Nonaccrual loans	710	5,000
Past Due
Past due financing receivables
Current Balance	6,141	5,075
30-59 Days Past Due
Past due financing receivables
Current Balance	4,395	879
Nonaccrual loans	2,900	55
60-89 Days Past Due
Past due financing receivables
Current Balance	782	245
Nonaccrual loans	31
Greater than 90 Days Past Due
Past due financing receivables
Current Balance	964	3,951
Nonaccrual loans	964	4,000
Real Estate Mortgage \| Construction and Land Development
Past due financing receivables
Total Financing Receivables	101,886	107,983
Nonaccrual loans	598	598
Real Estate Mortgage \| Construction and Land Development \| Current
Past due financing receivables
Current Balance	100,945	107,385
Real Estate Mortgage \| Construction and Land Development \| Past Due
Past due financing receivables
Current Balance	941	598
Real Estate Mortgage \| Construction and Land Development \| 60-89 Days Past Due
Past due financing receivables
Current Balance	343
Real Estate Mortgage \| Construction and Land Development \| Greater than 90 Days Past Due
Past due financing receivables
Current Balance	598	598
Real Estate Mortgage \| Residential Real Estate
Past due financing receivables
Total Financing Receivables	217,014	201,230
Nonaccrual loans	987	1,293
Real Estate Mortgage \| Residential Real Estate \| Current
Past due financing receivables
Current Balance	215,197	199,966
Real Estate Mortgage \| Residential Real Estate \| Past Due
Past due financing receivables
Current Balance	1,817	1,264
Real Estate Mortgage \| Residential Real Estate \| 30-59 Days Past Due
Past due financing receivables
Current Balance	1,359	658
Real Estate Mortgage \| Residential Real Estate \| 60-89 Days Past Due
Past due financing receivables
Current Balance	408	245
Real Estate Mortgage \| Residential Real Estate \| Greater than 90 Days Past Due
Past due financing receivables
Current Balance	50	361
Real Estate Mortgage \| Nonresidential
Past due financing receivables
Total Financing Receivables	690,788	642,217
Nonaccrual loans	2,562	6,486
Real Estate Mortgage \| Nonresidential \| Current
Past due financing receivables
Current Balance	687,510	639,302
Real Estate Mortgage \| Nonresidential \| Past Due
Past due financing receivables
Current Balance	3,278	2,915
Real Estate Mortgage \| Nonresidential \| 30-59 Days Past Due
Past due financing receivables
Current Balance	2,962
Real Estate Mortgage \| Nonresidential \| Greater than 90 Days Past Due
Past due financing receivables
Current Balance	316	2,915
Real Estate Mortgage \| Home Equity Loans
Past due financing receivables
Total Financing Receivables	31,650	30,395
Real Estate Mortgage \| Home Equity Loans \| Current
Past due financing receivables
Current Balance	31,605	30,235
Real Estate Mortgage \| Home Equity Loans \| Past Due
Past due financing receivables
Current Balance	45	160
Real Estate Mortgage \| Home Equity Loans \| 30-59 Days Past Due
Past due financing receivables
Current Balance	45	160
Commercial
Past due financing receivables
Total Financing Receivables	124,035	130,908
Nonaccrual loans	427	584
Commercial \| Current
Past due financing receivables
Current Balance	123,977	130,785
Commercial \| Past Due
Past due financing receivables
Current Balance	58	123
Commercial \| 30-59 Days Past Due
Past due financing receivables
Current Balance	27	46
Commercial \| 60-89 Days Past Due
Past due financing receivables
Current Balance	31
Commercial \| Greater than 90 Days Past Due
Past due financing receivables
Current Balance		77
Consumer and Other
Past due financing receivables
Total Financing Receivables	4,093	4,462
Consumer and Other \| Current
Past due financing receivables
Current Balance	4,091	4,447
Consumer and Other \| Past Due
Past due financing receivables
Current Balance	2	15
Consumer and Other \| 30-59 Days Past Due
Past due financing receivables
Current Balance	$ 2	$ 15

Amount of financing receivable on nonaccrual status.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123577603&loc=d3e5111-111524

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 16
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919258-210447

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (3)

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (2)

+ Details

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

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

- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124259787&loc=d3e4428-111522

+ Details

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

- Definition

Amount, before allowance for credit loss, of financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7A
-URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953401-111524

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 79
-URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919253-210447

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919230-210447

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 55
-Paragraph 80
-URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922355-210448

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (1)

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (2)

Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher SEC
-Name Regulation S-K (SK)
-Number 229
-Section 1404
-Paragraph (a)

+ Details

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

- Definition

Amount of deferred fees paid by borrowers and unamortized costs incurred to originate loans and leases, unamortized loan commitments and loan syndication fees, and premiums over or discounts from face amounts of loans that are being amortized into income as an adjustment to yield. Excludes amounts for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6378536&loc=d3e10092-111533

+ Details

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

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables30To59DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivables60To89DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=ptrs_RealEstatePortfolioSegmentMember
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_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ptrs_ResidentialRealEstateLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityLoanMember
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_FinancingReceivablePortfolioSegmentAxis=ptrs_ConsumerAndOtherPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: