Loans, net and allowance for credit losses- Major Classification of Loans by Past Due Status (Details) - USD ($) $ in Thousands	Sep. 30, 2025	Dec. 31, 2024
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	$ 4,016,367	$ 3,993,505
Loans > 90 Days and Accruing	886	458
Financial Assets, Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	17,607	29,841
30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	6,266	10,962
60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	2,779	3,093
Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	8,561	15,786
Financial Assets, Not Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	3,998,760	3,963,664
Commercial
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	664,615	648,102
Loans > 90 Days and Accruing	496
Commercial \| Financial Assets, Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	3,443	3,735
Commercial \| 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	1,064	2,740
Commercial \| 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	168	157
Commercial \| Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	2,211	838
Commercial \| Financial Assets, Not Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	661,172	644,367
Municipal
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	196,469	187,918
Municipal \| Financial Assets, Not Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	196,469	187,918
Commercial real estate
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	2,278,746	2,294,113
Commercial real estate \| Financial Assets, Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	4,929	14,105
Commercial real estate \| 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	1,021	2,800
Commercial real estate \| 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	92	141
Commercial real estate \| Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	3,816	11,164
Commercial real estate \| Financial Assets, Not Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	2,273,817	2,280,008
Residential real estate
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	588,519	551,383
Loans > 90 Days and Accruing	354	403
Loans in the formal process of foreclosure	700	200
Residential real estate \| Financial Assets, Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	3,419	5,864
Residential real estate \| 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	962	2,390
Residential real estate \| 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	842	997
Residential real estate \| Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	1,614	2,477
Residential real estate \| Financial Assets, Not Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	585,100	545,519
Consumer
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	114,510	132,869
Loans > 90 Days and Accruing	36	55
Consumer \| Financial Assets, Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	3,434	3,424
Consumer \| 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	2,341	2,393
Consumer \| 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	695	539
Consumer \| Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	398	492
Consumer \| Financial Assets, Not Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	111,076	129,445
Equipment financing
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	173,508	179,120
Equipment financing \| Financial Assets, Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	2,382	2,713
Equipment financing \| 30-59 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	878	639
Equipment financing \| 60-89 Days Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	982	1,259
Equipment financing \| Greater than 90 Days
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	522	815
Equipment financing \| Financial Assets, Not Past Due
Financing Receivable, Recorded Investment, Past Due.
Loans held for investment	$ 171,126	$ 176,407

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

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

Amortized cost of financing receivable 90 days or more past due and still accruing. Excludes net investment in lease.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-80

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 16
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-16

+ Details

Name:	us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing
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

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 7: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (d)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 8: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 9: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 10: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-14

Reference 12: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (e)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 13: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (e)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 14: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 15: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 16: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 12
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-12

Reference 17: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 80
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479294/326-20-55-80

+ Details

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

- Definition

Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 35
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-35

+ Details

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

- 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_FinancingReceivablesPeriodPastDueAxis=us-gaap_FinancialAssetNotPastDueMember
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=pfis_MunicipalPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ResidentialPortfolioSegmentMember
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_FinancingReceivablePortfolioSegmentAxis=pfis_EquipmentFinancingPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: