Investment securities - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
Mar. 31, 2015 Security	Mar. 31, 2014	Dec. 31, 2014 Security
Schedule of Available-for-sale Securities [Line Items]
Carrying value of securities pledged	$ 207,895,000		216,192,000
Number of investment securities held	63		52
State and Municipals, Tax-Exempt [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of investment securities held	36		16
Number of securities in continuous unrealized loss positions 12 months or longer	2		4
State and Municipals, Taxable [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of investment securities held	1		1
Number of securities in continuous unrealized loss positions 12 months or longer	1		1
Credit Concentration Risk [Member] \| Stockholders' Equity, Total [Member]
Schedule of Available-for-sale Securities [Line Items]
Maximum percentage of stockholders' equity exceeded for securities of any individual issuer	10.00%		10.00%
U.S. Government-Sponsored Enterprises State and Municipals [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of investment securities held	3		9
Number of securities in continuous unrealized loss positions 12 months or longer	1		2
Other-than-temporary impairments recognized	$ 0	$ 0
Mortgage-Backed Securities, U.S. Government-Sponsored Enterprises [Member]
Schedule of Available-for-sale Securities [Line Items]
Number of investment securities held	23		26
Number of securities in continuous unrealized loss positions 12 months or longer	2

Number of securities in continuous unrealized loss position.

No definition available.

Name:	pfis_NumberOfSecuritiesInContinuousUnrealizedLossPosition
Namespace Prefix:	pfis_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number Of Securities In Continuous Unrealized Loss Position 12 Months Or Longer

+ References

No definition available.

+ Details

Name:	pfis_NumberOfSecuritiesInContinuousUnrealizedLossPosition12MonthsOrLonger
Namespace Prefix:	pfis_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The fair value of available-for-sale securities that serve as collateral for borrowings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5086-111524

+ Details

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

- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 21

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13537-108611

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6404-108592

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13531-108611

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

-Paragraph 18

-URI http://asc.fasb.org/extlink&oid=6927468&loc=d3e6351-108592

+ Details

Name:	us-gaap_ConcentrationRiskPercentage1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount by which the fair value of an investment in debt securities categorized as Held-to-maturity is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563

+ Details

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

- Details

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

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=us-gaap_CreditConcentrationRiskMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_NontaxableMunicipalBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_InvestmentTypeAxis=us-gaap_TaxableMunicipalBondsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: