Loans, net and allowance for credit losses - Changes in Allowance for Loan Losses Account by Major Classification of Loans (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2024	Mar. 31, 2023
Allowance for loan losses:
Beginning Balance	$ 21,895	$ 27,472
Charge-offs	(108)	(75)
Recoveries	102	66
Provisions (credits)	708	1,244
Ending balance	22,597	25,444
Cumulative impact of adoption \| ASC 326
Allowance for loan losses:
Beginning Balance		(3,263)
Adjusted Balance
Allowance for loan losses:
Beginning Balance		24,209
Commercial
Allowance for loan losses:
Beginning Balance	2,272	4,365
Charge-offs	(5)	(4)
Recoveries	55
Provisions (credits)	(35)	(197)
Ending balance	2,287	2,481
Commercial \| Cumulative impact of adoption \| ASC 326
Allowance for loan losses:
Beginning Balance		(1,683)
Commercial \| Adjusted Balance
Allowance for loan losses:
Beginning Balance		2,682
Municipal
Allowance for loan losses:
Beginning Balance	788	1,247
Provisions (credits)	(90)	324
Ending balance	698	2,318
Municipal \| Cumulative impact of adoption \| ASC 326
Allowance for loan losses:
Beginning Balance		747
Municipal \| Adjusted Balance
Allowance for loan losses:
Beginning Balance		1,994
Commercial real estate
Allowance for loan losses:
Beginning Balance	14,153	17,915
Recoveries		1
Provisions (credits)	317	1,120
Ending balance	14,470	15,692
Commercial real estate \| Cumulative impact of adoption \| ASC 326
Allowance for loan losses:
Beginning Balance		(3,344)
Commercial real estate \| Adjusted Balance
Allowance for loan losses:
Beginning Balance		14,571
Residential real estate
Allowance for loan losses:
Beginning Balance	3,782	3,072
Recoveries	2	16
Provisions (credits)	474	(207)
Ending balance	4,258	3,868
Residential real estate \| Cumulative impact of adoption \| ASC 326
Allowance for loan losses:
Beginning Balance		987
Residential real estate \| Adjusted Balance
Allowance for loan losses:
Beginning Balance		4,059
Consumer
Allowance for loan losses:
Beginning Balance	900	873
Charge-offs	(103)	(71)
Recoveries	45	49
Provisions (credits)	42	204
Ending balance	$ 884	1,085
Consumer \| Cumulative impact of adoption \| ASC 326
Allowance for loan losses:
Beginning Balance		30
Consumer \| Adjusted Balance
Allowance for loan losses:
Beginning Balance		$ 903

Amount excluding accrued interest, of allowance for credit loss on 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

+ Details

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

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

- 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

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

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

- Details

Name:	srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201613Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustedBalanceMember
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: