Amount of credit enhancement for Mortgage Partnership Finance Program Portfolio losses by Federal Home Loan Bank.

No definition available.

Name:	czfs_FederalHomeLoanBankCreditEnhancementForMPFPortfolioLosses
Namespace Prefix:	czfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of first loss position maintained by Federal Home Loan Bank under Mortgage Partnership Finance Program.

+ References

No definition available.

+ Details

Name:	czfs_FederalHomeLoanBankFirstLossPositionForMPFPortfolio
Namespace Prefix:	czfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Refers to period of mortgage on residential real estate, measured in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	czfs_PeriodOfMortgageOnRealEstate
Namespace Prefix:	czfs_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Real estate loans serviced for Freddie Mac and Fannie Mae, which are not included in the consolidated balance sheet.

+ References

No definition available.

+ Details

Name:	czfs_RealEstateLoansServicedForFreddieMacAndFannieMae
Namespace Prefix:	czfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Real estate loans sold to Freddie Mac and Fannie Mae without recourse which are not included in the consolidated balance sheet.

+ References

No definition available.

+ Details

Name:	czfs_RealEstateLoansSoldToFreddieMacAndFannieMaeWithoutRecourse
Namespace Prefix:	czfs_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	czfs_SegmentsOfLoanPortfolioAndAllowanceForLoanLossesAbstract
Namespace Prefix:	czfs_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of allowance for credit loss on financing receivable. Excludes allowance for financing receivable covered under loss sharing agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(4))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (1)
-Publisher SEC

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

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

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-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 6: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7)(2))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479853/942-210-S99-1

Reference 7: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-11B

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479319/326-20-50-13

+ Details

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

- Definition

Amount of unamortized loan commitment, origination, and other costs (fees) on financing receivable recognized as adjustment to yield. Excludes financing receivable covered under loss sharing agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-4

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481598/310-20-45-1

Reference 3: http://www.xbrl.org/2003/role/recommendedDisclosureRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-SubTopic 20
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481569/310-20-50-3

+ Details

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

- Definition

Amount of investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column G))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479851/948-310-S99-1

+ Details

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

- Definition

Amortized cost, before allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

+ References

Reference 1: 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 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 79
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479294/326-20-55-79

Reference 3: 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 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (1)
-Publisher SEC

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Name Regulation S-K (SK)
-Number 229
-Section 1405
-Paragraph (a)
-Subparagraph (2)
-Publisher SEC

Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef
-Name Regulation S-K (SK)
-Number 229
-Section 1404
-Paragraph (a)
-Publisher SEC

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-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 9: http://www.xbrl.org/2003/role/disclosureRef
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-SubTopic 10
-Topic 310
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481962/310-10-50-7A

Reference 10: 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_NotesReceivableGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amortized cost, after allowance for credit loss, of financing receivable. Excludes financing receivable covered under loss sharing agreement and net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(5)(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479617/946-210-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481990/310-10-45-2

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

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_FirstMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_MortgageLoansOnRealEstateDescriptionLoanCategoryAxis=us-gaap_SecondMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
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_FinancingReceivablePortfolioSegmentAxis=czfs_RealEstateLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

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

LOANS AND RELATED ALLOWANCE FOR CREDIT LOSSES, Primary Segments Portfolio and Accretable Yield for PCI Loans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	$ 2,248,836	$ 1,724,999
Allowance for Credit Losses	21,153	18,552	$ 17,304	$ 15,815
Net loans	2,227,683	1,706,447
Net unamortized loan fees and costs	2,843	2,573
Real estate loans serviced for Freddie Mac and Fannie Mae	203,709	187,754
Real estate loans sold to Freddie Mac and Fannie Mae without recourse	193,548	177,575
Portfolio balance under MPF	10,161	10,179
First-loss position for MPF maintained by FHLB	165
Credit enhancement for MPF by FHLB	$ 229
First Mortgage [Member] \| Minimum [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Period of mortgage on real estate	15 years
First Mortgage [Member] \| Maximum [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Period of mortgage on real estate	30 years
Second Mortgage [Member] \| Maximum [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Period of mortgage on real estate	15 years
Residential [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	$ 310,199
Commercial [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	1,092,887
Construction [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	195,826
Real Estate Loans [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Net loans		296,863
Real Estate Loans [Member] \| Residential [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	359,990	210,213
Allowance for Credit Losses	2,354	1,056	1,147	1,174
Real Estate Loans [Member] \| Commercial [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	1,092,887	876,569
Allowance for Credit Losses	9,178	10,120	8,099	6,216
Net loans		876,569
Real Estate Loans [Member] \| Agricultural [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	314,802	313,614
Allowance for Credit Losses	3,264	4,589	4,729	4,953
Real Estate Loans [Member] \| Construction [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	195,826	80,691
Allowance for Credit Losses	1,950	801	434	122
Net loans		80,691
Consumer [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	61,316	86,650
Allowance for Credit Losses	1,496	135	262	321
Other Commercial Loans [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	136,168	63,222
Allowance for Credit Losses	2,229	1,040	1,023	1,226
Net loans		63,222
Other Agricultural Loans [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	30,673	34,832
Allowance for Credit Losses	270	489	558	864
Net loans		34,832
State and Political Subdivision Loans [Member]
Segments of loan portfolio and allowance for loan losses [Abstract]
Total loans	57,174	59,208
Allowance for Credit Losses	$ 45	322	$ 281	$ 479
Net loans		$ 59,208