LOANS AND ALLOWANCE FOR CREDIT LOSSES ON LOANS (Troubled Debt Restructuring by Portfolio Segment) (Details) $ in Thousands	3 Months Ended
Mar. 31, 2022 USD ($) loan	Mar. 31, 2021 USD ($) loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts \| loan	0	1
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0	$ 159
Financing Receivable, Troubled Debt Restructuring, Postmodification	0	170
Allowance Related to Troubled Debt Restructurings assigned during period	$ 0	$ 56
Home equity \| Interest Rate Concession and Payment Deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of Contracts \| loan	0	1
Financing Receivable, Troubled Debt Restructuring, Premodification	$ 0	$ 159
Financing Receivable, Troubled Debt Restructuring, Postmodification	0	170
Allowance Related to Troubled Debt Restructurings assigned during period	$ 0	$ 56

Allowance Related to Troubled Debt Restructurings assigned during period

No definition available.

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Namespace Prefix:	cac_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ References

+ Details

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

- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

+ Details

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Data Type:	xbrli:monetaryItemType
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- Details

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Namespace Prefix:
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Balance Type:
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- Details

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Namespace Prefix:
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Balance Type:
Period Type: