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Balance Type:	na
Period Type:	instant

Commercial loans as a percentage of gross loans.

No definition available.

Name:	caty_GrossLoansComprisedOfCommercialLoansPercentage
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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Commercial mortgage loans as a percentage of gross loans.

No definition available.

Name:	caty_GrossLoansComprisedOfCommercialMortgageLoansPercentage
Namespace Prefix:	caty_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Represents the minimum stock requirement on outstanding federal home loan bank borrowings, in shares.

No definition available.

Name:	caty_MinimumStockRequirementOnOutstandingFederalHomeLoanBankBorrowingsShares
Namespace Prefix:	caty_
Data Type:	xbrli:sharesItemType
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Period Type:	instant

Number of limited Partnerships in housing investments.

No definition available.

Name:	caty_NumberOfLimitedPartnershipsInHousingInvestments
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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

Percentage of subsidiaries common securities owned by parent company.

No definition available.

Name:	caty_PercentageOfSubsidiariesCommonSecuritiesOwnedByParentCompany
Namespace Prefix:	caty_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Residential mortgages properties percentage.

No definition available.

Name:	caty_ResidentialMortgagesPropertiesPercentage
Namespace Prefix:	caty_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

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Amount of impairment loss from asset representing future economic benefit arising from other asset acquired in business combination or from joint venture formation or both, that is not individually identified and separately recognized.

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