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, 2023	Mar. 31, 2022
Allowance for loan losses:
Beginning Balance	$ 27,472	$ 28,383
Charge-offs	(75)	(355)
Recoveries	66	79
Provisions (credits)	1,244	300
Ending balance	25,444	28,407
Cumulative impact of adoption \| ASU 2016-13
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	4,365	7,466
Charge-offs	(4)	(161)
Recoveries		9
Provisions (credits)	197	(887)
Ending balance	2,481	6,427
Commercial \| Cumulative impact of adoption \| ASU 2016-13
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	1,247	987
Provisions (credits)	324	179
Ending balance	2,318	1,166
Municipal \| Cumulative impact of adoption \| ASU 2016-13
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	17,915	15,928
Charge-offs		(132)
Recoveries	1	16
Provisions (credits)	1,120	977
Ending balance	15,692	16,789
Commercial real estate \| Cumulative impact of adoption \| ASU 2016-13
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	3,072	3,209
Recoveries	16	3
Provisions (credits)	207	43
Ending balance	3,868	3,255
Residential real estate \| Cumulative impact of adoption \| ASU 2016-13
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	873	793
Charge-offs	(71)	(62)
Recoveries	49	51
Provisions (credits)	204	(12)
Ending balance	1,085	$ 770
Consumer \| Cumulative impact of adoption \| ASU 2016-13
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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446

+ 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (e)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

+ 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (d)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

+ 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

+ 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: