CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (Parenthetical) - Transferred Securities $ in Millions	3 Months Ended
Jun. 30, 2022 USD ($)
AFS debt securities transferred to HTM, amortized cost	$ 592.4
AFS debt securities transferred to HTM, fair value	520.3
AFS debt securities, transfer, unrealized loss	$ 72.1

Debt Securities, Available-for-Sale, Amortized Cost, Transfer, Amount

No definition available.

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