LOANS AND ALLOWANCE FOR LOAN LOSSES (Summary of All Troubled Debt Restructuring Loans) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015 loan	Mar. 31, 2014 loan	Dec. 31, 2014 loan
Financing Receivable, Modifications [Line Items]
Number of Contracts	40		41
Recorded Investment	$ 5,800		$ 5,943
Specific Reserve	604		645
Number of Contracts	0	1
Pre-Modification Outstanding Recorded Investment	0	136
Post-Modification Outstanding Recorded Investment	0	149
Specific Reserve	0	45
Residential Real Estate
Financing Receivable, Modifications [Line Items]
Number of Contracts	23		24
Recorded Investment	3,659		3,786
Specific Reserve	591		635
Number of Contracts	0	1
Pre-Modification Outstanding Recorded Investment	0	136
Post-Modification Outstanding Recorded Investment	0	149
Specific Reserve	0	45
Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Number of Contracts	7		7
Recorded Investment	1,684		1,702
Specific Reserve	0		0
Commercial
Financing Receivable, Modifications [Line Items]
Number of Contracts	9		9
Recorded Investment	429		426
Specific Reserve	13		10
Consumer
Financing Receivable, Modifications [Line Items]
Number of Contracts	1		1
Recorded Investment	28		29
Specific Reserve	$ 0		$ 0

Allowance for Credit Losses, Related to Troubled Debt Restructured Loans

No definition available.

Name:	cac_AllowanceForCreditLossesRelatedToTroubledDebtRestructuredLoans
Namespace Prefix:	cac_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Allowance Related to Troubled Debt Restructuring assigned during period

+ References

No definition available.

+ Details

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

- Definition

Financing Receivable Modifications Number Of Contracts Outstanding

+ References

No definition available.

+ Details

Name:	cac_FinancingReceivableModificationsNumberOfContractsOutstanding
Namespace Prefix:	cac_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_FinancingReceivableModificationsLineItems
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/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Pre-modification amount of investment in financing receivables modified by troubled debt restructurings.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of the outstanding recorded investment related to financing receivables that have been modified by troubled debt restructurings.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 40

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=25495931&loc=d3e18845-111554

+ Details

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

- Details

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

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_CommercialRealEstatePortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableTroubledDebtRestructuringAxis=us-gaap_ResidentialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: