Servicing Assets, Fair Value Disclosure

No definition available.

Name:	cac_ServicingAssetsFairValueDisclosure
Namespace Prefix:	cac_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
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-Section 50
-Paragraph 1D
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+ Details

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

- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Publisher FASB
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+ Details

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

- Definition

Fair value as of the balance sheet date of all derivative assets not designated as hedging instruments.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=125515794&loc=SL5624163-113959

+ Details

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

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-URI http://asc.fasb.org/subtopic&trid=2196772

+ Details

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

- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

No definition available.

+ Details

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

- Definition

Fair value of an asset representing net future revenue from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
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-Section 45
-Paragraph 2
-Subparagraph (b)
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-Publisher FASB
-Name Accounting Standards Codification
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+ Details

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

- Definition

This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents the amount of short-term debt existing as of the balance sheet date.

+ References

No definition available.

+ Details

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

- Details

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Namespace Prefix:
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- Details

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- Details

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- Details

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Namespace Prefix:
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Balance Type:
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- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
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- Details

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- Details

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- Details

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Fair Value (Carrying Amounts and Estimated Fair Value for Financial Instrument Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financial assets:
Debt Securities, Held-to-maturity, Fair Value	$ 1,380	$ 1,411
HTM debt securities	1,291	1,297
Servicing Assets, Fair Value Disclosure	3,310	1,437
Servicing Asset at Fair Value, Amount	3,310	2,447	$ 1,496	$ 1,677
Financial liabilities:
Time deposits	409,264	460,278
Short-term Debt, Fair Value	211,586	162,420
Long-term Debt, Fair Value	0	25,442
Subordinated debentures	33,248	46,475
Readily Available Market Prices (Level 1) [Member]
Financial assets:
Debt Securities, Held-to-maturity, Fair Value	0	0
Servicing Assets, Fair Value Disclosure	0	0
Financial liabilities:
Time deposits	0	0
Short-term Debt, Fair Value	0	0
Long-term Debt, Fair Value	0	0
Subordinated debentures	0	0
Observable Market Data (Level 2) [Member]
Financial assets:
Debt Securities, Held-to-maturity, Fair Value	1,380	1,411
Servicing Assets, Fair Value Disclosure	0	0
Financial liabilities:
Time deposits	409,264	460,278
Short-term Debt, Fair Value	211,586	162,420
Long-term Debt, Fair Value	0	25,442
Subordinated debentures	33,248	46,475
Company Determined Fair Value (Level 3) [Member]
Financial assets:
Debt Securities, Held-to-maturity, Fair Value	0	0
Servicing Assets, Fair Value Disclosure	3,310	1,437
Financial liabilities:
Time deposits	0	0
Short-term Debt, Fair Value	0	0
Long-term Debt, Fair Value	0	0
Subordinated debentures	0	0
Carrying Amount [Member]
Financial assets:
HTM debt securities	1,291	1,297
Servicing Assets, Fair Value Disclosure	2,471	2,196
Financial liabilities:
Time deposits	409,668	457,694
Short-term Debt, Fair Value	211,608	162,439
Long-term Debt, Fair Value	0	25,000
Subordinated debentures	44,331	58,331
Residential real estate
Financial assets:
Loans receivable, net of allowance	1,297,592	1,066,991
Residential real estate \| Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Residential real estate \| Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Residential real estate \| Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	1,297,592	1,066,991
Residential real estate \| Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	1,300,314	1,051,324
Commercial real estate
Financial assets:
Loans receivable, net of allowance	1,435,794	1,307,132
Commercial real estate \| Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Commercial real estate \| Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Commercial real estate \| Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	1,435,794	1,307,132
Commercial real estate \| Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	1,474,087	1,344,860
Commercial
Financial assets:
Loans receivable, net of allowance	356,463	372,194
Commercial \| Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Commercial \| Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Commercial \| Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	356,463	372,194
Commercial \| Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	359,512	374,791
Home equity
Financial assets:
Loans receivable, net of allowance	205,920	253,276
Home equity \| Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Home equity \| Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Home equity \| Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	208,934	253,276
Home equity \| Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	208,934	255,957
Consumer
Financial assets:
Loans receivable, net of allowance	17,551	18,102
Consumer \| Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Consumer \| Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
Consumer \| Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	17,551	18,102
Consumer \| Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	19,437	19,999
SBA PPP Portfolio Segment
Financial assets:
Loans receivable, net of allowance	37,133	137,209
SBA PPP Portfolio Segment \| Readily Available Market Prices (Level 1) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
SBA PPP Portfolio Segment \| Observable Market Data (Level 2) [Member]
Financial assets:
Loans receivable, net of allowance	0	0
SBA PPP Portfolio Segment \| Company Determined Fair Value (Level 3) [Member]
Financial assets:
Loans receivable, net of allowance	37,133	137,209
SBA PPP Portfolio Segment \| Carrying Amount [Member]
Financial assets:
Loans receivable, net of allowance	35,934	135,026
Interest Rate Lock Commitments [Member] \| Fair Value, Measurements, Recurring [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	371	608
Interest Rate Lock Commitments [Member] \| Fair Value, Measurements, Recurring [Member] \| Observable Market Data (Level 2) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	371	608
Forward Contracts [Member] \| Fair Value, Measurements, Recurring [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	86	311
Forward Contracts [Member] \| Fair Value, Measurements, Recurring [Member] \| Observable Market Data (Level 2) [Member]
Financial assets:
Interest Rate Derivative Instruments Not Designated as Hedging Instruments, Asset at Fair Value	$ 86	$ 311