Document And Entity Information
Statistical Measurement [Axis]
Note To Financial Statement Details Textual
Note 4 - Investment Securities
Note 5 - Loans
Income tax expense
us-gaap_IncomeTaxExpenseBenefit
ecd_NonRule10b51ArrTrmntdFlag
Non-Rule 10b5-1 Arrangement Terminated [Flag]
Note 7 - Goodwill and Other Intangible Assets
ecd_NonRule10b51ArrAdoptedFlag
Non-Rule 10b5-1 Arrangement Adopted [Flag]
Note 10 - Stockholders' Equity
Trading Arrangements, by Individual [Table]
Note 11 - Earnings Per Share
Material Terms of Trading Arrangement [Text Block]
Note 12 - Stock-based Compensation
Deposit Account [Member]
Note 14 - Fair Value Measurements and Fair Value of Financial Instruments
Financial Instrument [Axis]
Note 15 - Financial Derivatives
Investment in Debt and Equity Securities and Other Trading Assets [Text Block]
Note 16 - Balance Sheet Offsetting
Note 17 - Revenue From Contracts With Clients
Minimum [Member]
Note 4 - Investment Securities - Investment Securities (Details)
Investment securities available for sale, gross unrealized losses
Note 4 - Investment Securities - Investments by Contractual Maturity Date (Details)
Investment securities available for sale, gross unrealized gains
Statistical Measurement [Domain]
Note 4 - Investment Securities - Temporarily Impaired Securities (Details)
Maximum [Member]
Amortization on alternative energy partnerships, venture capital and other investments
The sum of the periodic adjustments of the differences between investments' face values and purchase prices that are charged against earnings. This is called accretion if the investment was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.
Note 5 - Loans - Components of Loans in Consolidated Balance Sheets (Details)
Share Repurchase Program [Axis]
Note 5 - Loans - Nonaccrual Loans and Related Allowance for Credit Losses (Details)
Share Repurchase Program [Domain]
Note 5 - Loans - Average Balance and Interest Income Recognized Related to Non-accrual Loans (Details)
Note 5 - Loans - Aging of Loan Portfolio (Details)
Note 5 - Loans - Amortized Cost of Modified Loans (Details)
Note 5 - Loans - Performance of Modified Loans (Details)
Note 5 - Loans - Loan Held for Investment by Loan Portfolio Segments, Internal Risk Ratings and Vintage Year (Details)
Note 5 - Loans - Allowance for Loan Losses by Portfolio Segment (Details)
Note 7 - Goodwill and Other Intangible Assets - Schedule of Intangible Assets (Details)
Note 7 - Goodwill and Other Intangible Assets - Maturity Schedule of Intangible Assets (Details)
Note 10 - Stockholders' Equity - Accumulated Other Comprehensive Income (Details)
Note 11 - Earnings Per Share - Earnings Per Share (Details)
Note 12 - Stock-based Compensation - Restricted Stock Units (Details)
Note 14 - Fair Value Measurements and Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details)
Note 14 - Fair Value Measurements and Fair Value of Financial Instruments - Financial Assets Measured on a Non-recurring Basis (Details)
Note 14 - Fair Value Measurements and Fair Value of Financial Instruments - Fair Value of Financial Instruments (Details)
Note 14 - Fair Value Measurements and Fair Value of Financial Instruments - Fair Value Hierarchy of Financial Instruments (Details)
Note 15 - Financial Derivatives - Not Designated as Hedging (Details)
Note 15 - Financial Derivatives - Cash Flow Swap Hedges (Details)
Commercial Mortgage-Backed Securities [Member]
Note 16 - Balance Sheet Offsetting - Financial Instruments That Are Eligible for Offset in the Consolidated Balance Sheet (Details)
Note 17 - Revenue From Contracts With Clients - Summary of Revenue (Details)
Notes To Financial Statements
us-gaap_JuniorSubordinatedLongTermNotes
Junior Subordinated Notes, Noncurrent
Counterparty Name [Axis]
Notes To Financial Statements [Abstract]
Junior Subordinated Debt [Member]
us-gaap_EffectiveIncomeTaxRateContinuingOperations
Effective Income Tax Rate Reconciliation, Percent
caty_DerivativeOutstandingNotionalAmount
Derivative Outstanding, Notional Amount
Outstanding notional amount specified by the derivative(s). Expressed as an absolute value.
Higher-yielding Securities [Member]
Relating to higher yielding securities.
us-gaap_DividendsCommonStockCash
Dividends, Common Stock, Cash
Cash dividends
Income Tax Jurisdiction [Domain]
Installment and Other Loans [Member ]
The installment and other loans.
Residential Mortgage and Equity Lines [Member]
The residential mortgage and equity lines.
Financial Instruments [Domain]
Asset Pledged as Collateral [Member]
Counterparty Name [Domain]
us-gaap_SharesOutstanding
Balance (in shares)
Balance (in shares)
Other real estate owned expense/(income)
Amount of expense (income) recognized during the period for the foreclosure on real estate assets.
Temporarily impaired securities, 12 months or longer, fair value
Temporarily impaired securities, 12 months or longer, fair value
Temporarily impaired securities, less than 12 months, fair value
Award Type [Axis]
Adjustments to reconcile net income to net cash provided by operating activities:
us-gaap_Liabilities
Total liabilities
us-gaap_AllocatedShareBasedCompensationExpense
Share-Based Payment Arrangement, Expense
us-gaap_LiabilitiesAndStockholdersEquity
Total liabilities and stockholders' equity
Pledged Status [Domain]
Pledged Status [Axis]
Subsequent Event [Member]
Asset Not Pledged as Collateral [Member]
Short-term investments
caty_ShorttermInvestmentFairValueDisclosure
Fair value portion of short-term investments.
Share-Based Payment Arrangement [Text Block]
us-gaap_RestrictedCash
Restricted Cash
Portion at Fair Value Measurement [Member]
Reported Value Measurement [Member]
Fair Value, by Balance Sheet Grouping [Table]
Proceeds from shares issued under Dividend Reinvestment Plan
Proceeds from Issuance of Common Stock, Dividend Reinvestment Plan
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect
(Decrease)/increase in cash, cash equivalents, and restricted cash
Computer and equipment expense
Cash and due from banks
us-gaap_CashAndCashEquivalentsFairValueDisclosure
Cash and due from banks
Estimate of Fair Value Measurement [Member]
Cash dividends per share (in dollars per share)
Cash dividends paid per common share (in dollars per share)
US Government-sponsored Enterprises Debt Securities [Member]
us-gaap_CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsIncludingDisposalGroupAndDiscontinuedOperations
Cash, cash equivalents, and restricted cash, beginning of the period
Cash, cash equivalents, and restricted cash, end of the period
Share-Based Payment Arrangement, Tranche One [Member]
Performance-based Restricted Stock Units [Member]
Information related to performance-based restricted stock units.
Statement [Table]
Time-based Restricted Stock Units [Member]
Information related to time-based restricted stock units.
California Franchise Tax Board [Member]
Time deposits
Income Tax Authority, Name [Axis]
Income Tax Authority, Name [Domain]
Temporarily impaired securities, total unrealized losses
Loans held for investment, net
us-gaap_LoansReceivableFairValueDisclosure
Loans held for investment, net
Temporarily impaired securities, total fair value
Equity securities
us-gaap_EquitySecuritiesFvNi
Equity securities
Common Stock Outstanding [Member]
Stock outstanding which is subordinate to all other stock of the issuer.
Investment in Federal Home Loan Bank stock
us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure
Investment in Federal Home Loan Bank stock
Derivative liabilities, net
us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionNumberOfPositions
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions
Financing Receivable, Allowance for Credit Loss [Table Text Block]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber
Balance (in shares)
Balance (in shares)
us-gaap_EquitySecuritiesFvNiUnrealizedGain
Equity Securities, FV-NI, Unrealized Gain
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue
Balance, weighted-average grant date fair value (in dollars per share)
Balance, weighted-average grant date fair value (in dollars per share)
Nature of Operations [Text Block]
srt_StockRepurchaseProgramAuthorizedAmount1
Share Repurchase Program, Authorized, Amount
Financing Receivable, Past Due [Table Text Block]
Granted (in shares)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod
Granted, weighted-average grant date fair value (in dollars per share)
Long-Term Debt, Type [Axis]
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod
Forfeited (in shares)
Equity securities (including $26,482 measured at fair value at June 30, 2026, and $32,754 at December 31, 2025)
Equity Securities, FV-NI, Cost
Net gains/(losses) from equity securities
Stock issued to directors (in shares)
Product and Service [Domain]
Product and Service [Axis]
Vested, weighted-average grant date fair value (in dollars per share)
us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss
Equity Securities, FV-NI, Unrealized Gain (Loss)
Unrealized (gain)/ loss on equity securities
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Amount
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod
Vested (in shares)
Collateralized Mortgage Obligations [Member]
Stock-based compensation and stock issued to officers as compensation
Asset Class [Axis]
Derivative liabilities, financial instrument not offset
Loans receivable
us-gaap_LoansReceivableHeldForSaleReconciliationToCashFlowDeductionsFromHeldForSale
Financing Receivable, Held-for-Sale, Not Part of Disposal Group, Reconciliation to Cash Flow, Deduction from Held-for-Sale
Derivative assets, financial instrument not offset
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)
Commitments to Extend Credit [Member]
us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend
Financing Receivable, Troubled Debt Restructuring, Commitment to Lend
Assets
Measurement Frequency [Axis]
Commitments and Contingencies Disclosure [Text Block]
Statement [Line Items]
Fair Value Hierarchy and NAV [Axis]
Common stock, shares issued (in shares)
Common stock, shares outstanding (in shares)
Award Type [Domain]
Common stock, shares authorized (in shares)
Advances from Federal Home Loan Bank
Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block]
Schedule of Share-Based Compensation Arrangements by Share-Based Payment Award [Table]
Common stock, $0.01 par value, 100,000,000 shares authorized; 91,914,036 issued and 66,825,367 outstanding at June 30, 2026, and 91,803,148 issued and 67,200,126 outstanding at December 31, 2025
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
2027
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
2028
us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
2026
us-gaap_PolicyTextBlockAbstract
Accounting Policies
us-gaap_DisclosureTextBlockAbstract
Notes to Financial Statements
us-gaap_TableTextBlock
Notes Tables
us-gaap_ComprehensiveIncomeNetOfTax
Total comprehensive income
us-gaap_ShortTermInvestments
Short-term investments
Subsequent Events [Text Block]
us-gaap_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresAmountOfAvailableUnusedFunds
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds
Significant Accounting Policies [Text Block]
Proceeds from repayments, maturities and calls of securities available-for-sale
Amortization of right-of-use asset
Lease liabilities - operating leases
Deposits
us-gaap_DepositsFairValueDisclosure
Deposits
Capitalization, Equity [Table]
Proceeds from sale of loans originally classified as held-for-investment
Income Tax Jurisdiction, Domestic Federal [Member]
Federal Home Loan Bank stock
Income Tax Jurisdiction, Domestic State and Local [Member]
Long-term debt
Offsetting Assets [Table]
Payment Deferral [Member]
Statement of Stockholders' Equity [Abstract]
Intangible Asset, Finite-Lived, Class [Axis]
Proceeds from sale of other real estate owned
Extended Maturity [Member]
Loan Restructuring Modification [Axis]
Equity securities, fair value
Equity Securities, FV-NI
Intangible Asset, Finite-Lived, Class [Domain]
Loan Restructuring Modification [Domain]
Derivatives, collateral posted
Statement of Cash Flows [Abstract]
Financing Receivable Portfolio Segment [Axis]
Statutory Accounting Practices [Table]
Other comprehensive income (loss)
Other comprehensive income
Long-Term Debt, Type [Domain]
Stockholders’ Equity
Equity Components [Axis]
Core Deposits [Member]
Stock issued to directors
caty_StockIssuedDuringPeriodValueIssuedForServicesNet
Stock Issued During Period, Value, Issued for Services, Net
Value of stock issued in lieu of cash for services contributed to the entity. Value of the stock issued includes, but is not limited to, services contributed by vendors and founders.
Change in operating lease liabilities
Financing Receivable Portfolio Segment [Domain]
Equity Component [Domain]
us-gaap_ForeignCurrencyFairValueHedgeLiabilityAtFairValue
Foreign exchange contracts
Fair Value Measurements, Nonrecurring [Table Text Block]
Fair Value, Inputs, Level 2 [Member]
us-gaap_ForeignCurrencyFairValueHedgeAssetAtFairValue
Foreign exchange contracts
Fair Value, Inputs, Level 3 [Member]
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Equity [Text Block]
Fair Value, Inputs, Level 1 [Member]
AOCI Attributable to Parent [Member]
Additional Paid-in Capital [Member]
Retained Earnings [Member]
Corporate Debt Securities [Member]
ILLINOIS
HONG KONG
us-gaap_DerivativeLiabilityFairValueOfCollateral
Derivatives, collateral posted
Schedule of Gain (Loss) on Securities [Table]
Stock Repurchase Program Authorized June 4, 2025 [Member]
Represents Stock Repurchase Program Authorized June 4, 2025.
Premises and equipment, net
Financial Asset, Aging [Axis]
MARYLAND
Subsequent Event Type [Domain]
Financing Receivable, Nonaccrual [Table Text Block]
Doubtful
Loans
Subsequent Event [Table]
Subsequent Event Type [Axis]
Financial Asset, Aging [Domain]
Provision for credit losses
NEW YORK
WASHINGTON
Financial Asset, 30 to 59 Days Past Due [Member]
Debt securities, available-for-sale, amortized cost
Total, amortized cost
Investment securities available for sale, amortized cost
Stock-based compensation
TEXAS
Net unrealized (losses)/gains arising during the period, tax
Intangible Asset and Goodwill [Text Block]
us-gaap_ReclassificationFromAociCurrentPeriodTax
Reclassification adjustment for net losses/(gains) included in net income, tax
caty_CommitmentsToFundAdjustableRateLoans
Commitments to Fund Adjustable Rate Loans
Commitments to fund adjustable rate loans.
caty_CommitmentsToFundFixedRateLoans
Commitments to Fund Fixed Rate Loans
Commitments to fund fixed rate loans.
us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Less: Allowance for loan losses
Balance
Balance
Financial Asset, 60 to 89 Days Past Due [Member]
Share-Based Payment Arrangement, Restricted Stock Unit, Activity [Table Text Block]
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
us-gaap_DebtSecuritiesAvailableForSaleAmortizedCostAllowanceForCreditLossExcludingAccruedInterest
Debt Securities, Available-for-Sale, Allowance for Credit Loss, Excluding Accrued Interest
Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block]
Originated four years prior
Originated years prior
Originated two years prior
Originated three years prior
Fair Value Disclosures [Text Block]
Originated current year
Fair Value, by Balance Sheet Grouping [Table Text Block]
Originated prior year
Supplemental Cash Flow Information
Derivatives Not Designated as Hedging Instruments [Table Text Block]
Revolving
us-gaap_ImpairmentOfIntangibleAssetsFinitelived
Intangible Asset, Finite-Lived, Impairment Loss
Converted to Term
Impaired Loans [Member]
Information regarding impaired loans.
us-gaap_MarginDepositAssets
Margin Deposit Assets
Other Real Estate Owned [Member]
Information relating to other real estate owned.
us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments
Amortization/accretion of securities available-for-sale premiums/discounts, net
Investments in Venture Capital [Member]
Represents investments in venture capital.
Treasury Stock [Text Block]
Long-term debt
us-gaap_LongTermDebtFairValue
Long-term debt
Allowance
Allowance on financing receivable on nonaccrual status.
Loans with related allowance, unpaid principal balance
Unpaid principal balance of financing receivable on nonaccrual status with allowance. Excludes net investment in lease.
Unpaid principal balance
Unpaid principal balance of financing receivable on nonaccrual status. Excludes net investment in lease.
Spot, Forward, and Swap Contracts with Negative Fair Value [Member]
Represents the spot, forward, and swap contracts with negative fair value.
Spot, Forward, and Swap Contracts with Positive Fair Value [Member]
Represents the spot, forward, and swap contracts with positive fair value.
Periodic net settlement of swaps
The amount of expense of periodic net settlements on interest rate swaps.
Loans with related allowance, recorded investment
Amortized cost of financing receivable on nonaccrual status with allowance. Excludes net investment in lease.
Average Recorded Investment
Amount of average recorded investments of financing receivable on nonaccrual status. Excludes net investment in lease.
Loans Receivable with Partial-term Hedging Designation [Member]
Represents information to loans receivable with partial-term hedging designation.
Income taxes
Schedule of Nonaccrual Loans and Related Allowance and Charge Off [Table Text Block]
Tabular disclosure of nonaccrual loans and related allowance and charge-offs.
Loans with no related allowance, unpaid principal balance
Unpaid principal balance of financing receivable on nonaccrual status with no allowance. Excludes net investment in lease.
Marketing expense
Salaries and employee benefits
Financing Receivable, Modified, Performance [Table Text Block]
Tabular disclosure of performance of financing receivable modified for debtor experiencing financial difficulty.
Customers’ liability on acceptances
Weighted average payment deferral (Year)
Period of payment deferral in weighted average of financing receivable modified for debtor experiencing financial difficulty, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
Federal Home Loan Bank Securities [Member]
Relating to Federal Home Loan Bank Securities.
Financial Asset, 30 to 89 Days Past Due [Member]
Financial asset more than 29 days past due but fewer than 90 days past due.
Derivative Instruments and Hedging Activities Disclosures [Table]
Other real estate owned, net
Other Commitments [Table]
us-gaap_GainLossOnSaleOfPropertyPlantEquipment
Loss on sales or disposal of premises and equipment
Accumulated other comprehensive loss, net
Financing Receivable, Modified, Amortized Cost [Table Text Block]
Tabular disclosure of amortized cost of financing receivable modified for debtor experiencing financial difficulty.
us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization
Accumulated amortization
Schedule of Amounts Recognized in Balance Sheet [Table Text Block]
us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest
Income before income tax expense
Data processing service expense
Additional paid-in-capital
Debt Disclosure [Text Block]
us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)
us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)
Unrealized Gain (Loss) on Investments [Table Text Block]
Share-Based Payment Arrangement, Cliff Vesting [Member]
Pertains to cliff-vesting under under share-based payment arrangement.
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]
us-gaap_PaymentsToAcquirePropertyPlantAndEquipment
Purchase of premises and equipment
Collateralized Mortgage-Backed Securities [Member]
Dividend Reinvestment Plan
us-gaap_NoninterestExpense
Total non-interest expense
Non-Interest Expense
Other Service Fees [Member]
Represents the information pertaining to other service fees.
Wealth Management Fees [Member]
Represents the information pertaining to the wealth management fees.
Financial Asset, Not Past Due [Member]
Restricted stock units vested
Non-interest gain, not in-scope(2)
Amount of noninterest income (loss) that are out of the scope of ASC 606.
Fair Value, Recurring and Nonrecurring [Table]
Average restricted stock units with anti-dilutive effect (in shares)
Represents the average shares of stock options and restricted stock units with anti-dilutive effect.
Restricted Stock Units (RSUs) [Member]
Debt Instrument, Name [Domain]
Dividend Reinvestment Plan (in shares)
us-gaap_ReclassificationFromAociCurrentPeriodNetOfTaxAttributableToParent
Reclassification adjustment for net losses/(gains) included in net income, net of tax
Net unrealized (losses)/gains arising during the period, net of tax
Central Counterparties (CCP) [Member]
Represents Central Counterparties (CCP).
us-gaap_ReclassificationFromAociCurrentPeriodBeforeTaxAttributableToParent
Net unrealized (losses)/gains arising during the period, pre-tax
Restricted stock units vested (in shares)
us-gaap_DebtInstrumentInterestRateEffectivePercentage
Debt Instrument, Interest Rate, Effective Percentage
Net unrealized (losses)/gains arising during the period, pre-tax
Bank [Member]
Information relating to the Bank
us-gaap_TreasuryStockSharesAcquired
Treasury Stock, Shares, Acquired (in shares)
Purchases of treasury stock (in shares)
caty_FinitelivedIntangibleAssetsAccumulatedImpairment
Impairment
The amount of accumulated impairment loss resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.
Schedule of Long-Term Debt Instruments [Table]
Debt Instrument [Axis]
us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount
Debt Instrument, Unused Borrowing Capacity, Amount
Fees and Services Charges on Deposit Account [Member]
Represents the information pertaining to fees and services charges on deposit accounts.
Cash Flows from Operating Activities
Cash Flows from Investing Activities
us-gaap_NetCashProvidedByUsedInOperatingActivities
Net cash provided by operating activities
Cash Flows from Financing Activities
us-gaap_NetCashProvidedByUsedInInvestingActivities
Net cash used for investing activities
us-gaap_TreasuryStockAcquiredAverageCostPerShare
Shares Acquired, Average Cost Per Share (in dollars per share)
Intangible Asset, Finite-Lived, and Capitalized Cost, Software to be Sold, Leased, or Marketed, Estimated Amortization Expense [Table Text Block]
us-gaap_NetCashProvidedByUsedInFinancingActivities
Net cash provided for financing activities
Advances from the Federal Home Loan Bank
Advance from Federal Home Loan Bank
us-gaap_PaymentsToAcquireAvailableForSaleSecuritiesDebt
Payments to Acquire Debt Securities, Available-for-Sale
Purchase of securities available-for-sale
Proceeds from sale of securities available-for-sale
us-gaap_LiabilitiesFairValueDisclosure
Liabilities, fair value disclosure
Total at Fair Value
Assets, fair value disclosure
Affordable housing investments and alternative energy partnerships, net
Amount of investments in affordable housing and alternative energy partnerships.
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]
us-gaap_GoodwillImpairmentLoss
Goodwill, Impairment Loss
Increase in deposits
US Government Corporations and Agencies Securities [Member]
Net gain/(loss)(1)
Accounting Policies [Abstract]
Accounting Standards Update and Change in Accounting Principle [Text Block]
US Treasury Securities [Member]
us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss
Loans held for investment, net
Internal Revenue Service (IRS) [Member]
us-gaap_PaymentsForProceedsFromLoansAndLeases
Net increase in loans
Income Statement [Abstract]
Securities AFS
Securities available-for-sale at fair value (amortized cost of $1,737,212 at June 30, 2026, and $1,735,451 at December 31, 2025)
Debt Securities, Available-for-Sale, Excluding Accrued Interest
Total, fair value
Securities available-for-sale
us-gaap_TreasuryStockCommonValue
Treasury stock, at cost (25,088,669 shares at June 30, 2026, and 24,603,022 shares at December 31, 2025)
Treasury stock, shares (in shares)
Schedule of Available-for-Sale Securities Reconciliation [Table Text Block]
Treasury Stock, Common [Member]
Net income
Net income
Net Income (Loss) Attributable to Parent
Net income
Financial Asset, Past Due [Member]
Amortization of core deposit intangibles
Intangible Asset, Finite-Lived, Amortization Expense
Provision for losses on other real estate owned
Amount of provision (reversal) related to other real estate owned based on the assessment of uncollectability from the counterparty to reduce the account to their net realizable value.
Income Tax, Examination [Table]
us-gaap_InterestIncomeExpenseNet
Net interest income before provision for credit losses
Accumulated Other Comprehensive Income (Loss) [Table]
Income Tax Disclosure [Text Block]
caty_NetIncreaseInInvestmentInAffordableHousingInvestingAndAlternativeEnergyPartnerships
Net (increase)/decrease in affordable housing investments and alternative energy partnerships
Amount of net increase (decrease) in investment in affordable housing and alternative energy partnerships during the period.
us-gaap_StockholdersEquityPeriodIncreaseDecrease
Stockholders' Equity, Period Increase (Decrease)
Interest Income Recognized
Accounting Standards Update and Change in Accounting Principle [Table]
caty_PercentageOfSubsidiariesCommonSecuritiesOwnedByParentCompany
Percentage of Subsidiaries Common Securities Owned by Parent Company
Percentage of subsidiaries common securities owned by parent company.
Total Losses
Occupancy expense
Other operating expense
FDIC and regulatory assessments
us-gaap_TreasuryStockValueAcquiredCostMethod
Treasury Stock, Value, Acquired, Cost Method
Purchases of treasury stock
us-gaap_NoninterestIncome
Total non-interest income
Total non-interest income
Non-Interest Income
Supplemental Balance Sheet Disclosures [Text Block]
Measurement Basis [Axis]
us-gaap_GainsLossesOnSalesOfOtherRealEstate
Net gains on sale and transfers of other real estate owned
Other operating income
Fair Value Hierarchy and NAV [Domain]
us-gaap_GainLossOnSalesOfLoansNet
Net gains on sale of loans
Measurement Frequency [Domain]
us-gaap_OpenTaxYear
Open Tax Year
Vesting [Axis]
Statement of Financial Position [Abstract]
Vesting [Domain]
Net loss on sale of investment securities
Net loss on investment securities
Represents the amount of impairment on investment securities.
Class of Treasury Stock [Table]
Provision/(reversal) for expected credit losses
Stock Repurchase Program Authorized April 23, 2026 [Member]
Relating to stock repurchase program authorized April 23, 2026.
Recoveries
Other assets
Loans, write offs
Charge-offs
us-gaap_DebtSecuritiesAvailableForSaleExcludingAccruedInterestAllowanceForCreditLossNotToSellBeforeRecoveryCreditLossPreviouslyRecordedExpenseReversal
Debt Securities, Available-for-Sale, Excluding Accrued Interest, Allowance for Credit Loss, Not to Sell before Recovery, Credit Loss, Previously Recorded, Expense (Reversal)
Preferred Stock of Government Sponsored Entities [Member]
This item represents investments in preferred stock of government sponsored entities.
Professional services expense
Fair Value, Nonrecurring [Member]
Other Equity Securities [Member]
Equity securities not otherwise classified.
Fair Value, Recurring [Member]
Mutual Funds [Member]
Represents mutual funds.
caty_PaymentsForProceedsFromRepurchaseOfCommonStock
Purchases of treasury stock
The amount of cash outflow (inflow) from repurchase of common stock.
us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffAfterRecovery
Net (charge-offs)/recoveries
us-gaap_IncreaseDecreaseInOtherOperatingAssets
Net change in accrued interest receivable and other assets
us-gaap_IncreaseDecreaseInDeferredIncomeTaxes
Deferred tax provision
Document Type
Acceptances outstanding
Document Information [Line Items]
Document Quarterly Report
Document Information [Table]
Entity Interactive Data Current
Document Transition Report
Diluted (in shares)
us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Diluted weighted-average number of common shares outstanding (in shares)
Net Income Per Common Share:
Dilutive effect of weighted-average outstanding common share equivalents RSUs (in shares)
Basic (in shares)
us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Basic weighted-average number of common shares outstanding (in shares)
us-gaap_DebtInstrumentTerm
Debt Instrument, Term (Year)
Derivative Instrument [Axis]
Basic (in dollars per share)
us-gaap_EarningsPerShareBasic
Loans with no related allowance, recorded investment
Earnings Per Share, Diluted, by Common Class, Including Two-Class Method [Table]
Recorded investment
Financing Receivable, Excluding Accrued Interest, Nonaccrual
us-gaap_TransferOfPortfolioLoansAndLeasesToHeldForSale1
Loan and Lease, Transfer from Held-in-Portfolio to Held-for-Sale
Federal Reserve Bank’s Discount Window [Member]
Represents the Federal Reserve Bank’s Discount Window.
us-gaap_Deposits
Total deposits
Loans transferred from held-for-investment to held-for-sale
Income Tax Jurisdiction [Axis]
Other intangible assets, net
Money market deposits
NOW deposits
Deposits:
Interest-bearing:
Non-interest-bearing
us-gaap_FiniteLivedIntangibleAssetsNet
Net carrying balance
Total
Document Fiscal Period Focus
Pledging Purpose [Axis]
Gross balance
Document Fiscal Year Focus
Pledging Purpose [Domain]
Commercial Loans [Member]
A debt-based funding arrangement that a business can set up with a financial institution. The proceeds of commercial loans may be used to fund large capital expenditures and/or operations that a business may otherwise be unable to afford.
Savings deposits
Amendment Flag
Equity Securities without Readily Determinable Fair Value [Table]
Weighted average fixed rate-pay
Financing Receivable, Past Due [Table]
Unamortized deferred loan fees, net
Weighted average variable rate spread
Goodwill
Goodwill
us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
Net change in other liabilities
Document Period End Date
Legal Entity [Axis]
Residential Portfolio Segment [Member]
us-gaap_InterestAndDividendIncomeOperating
Total interest and dividend income
Commercial Real Estate Portfolio Segment [Member]
Weighted average variable rate-receive
Financing Receivable, Allowance for Credit Loss [Table]
Commercial Portfolio Segment [Member]
us-gaap_DerivativeFairValueOfDerivativeNet
Fair value
Entity File Number
Entity Tax Identification Number
Non-cash investing and financing activities:
Derivative assets, gross
Derivative liabilities, gross
Disaggregation of Revenue [Table Text Block]
Temporarily impaired securities, less than 12 months, unrealized losses
Disaggregation of Revenue [Table]
Entity [Domain]
Temporarily impaired securities, 12 months or longer, unrealized losses
Entity Central Index Key
Entity Registrant Name
us-gaap_DerivativeLossOnDerivative
Derivative, Loss on Derivative
Doubtful [Member]
Entity Current Reporting Status
us-gaap_DebtSecuritiesAvailableForSaleRealizedLoss
Debt Securities, Available-for-Sale, Realized Loss
Special Mention [Member]
us-gaap_DerivativeGainOnDerivative
Derivative, Gain on Derivative
Substandard [Member]
Entity Incorporation, State or Country Code
Pass [Member]
Current Fiscal Year End Date
Entity Filer Category
Entity Shell Company
Entity Emerging Growth Company
us-gaap_OtherComprehensiveIncomeLossNetOfTax
Other Comprehensive Income (Loss), Net of Tax
Notional amount
Notional
Derivative, Notional Amount
Entity Small Business
Investments [Domain]
Hedging Designation [Domain]
Residential Mortgage Loans [Member]
Class of financing receivable classified as residential mortgage loans.
Derivative assets, net
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]
Interest Expense
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Interest rate swaps
us-gaap_DerivativeAssetNotionalAmount
Interest rate swaps
us-gaap_DerivativeLiabilityNotionalAmount
Entity Address, State or Province
Entity Address, City or Town
Marketable Securities [Table]
us-gaap_InterestExpenseTimeDeposits
Time deposits
Retained earnings
us-gaap_InterestExpenseOperating
Total interest expense
Entity Address, Address Line One
City Area Code
Due after one year through five years, Amortized Cost
us-gaap_PaymentsRelatedToTaxWithholdingForShareBasedCompensation
Taxes paid related to net share settlement of RSUs
Due after five years through ten years, Amortized Cost
Local Phone Number
Due in one year or less, Amortized Cost
Revenue from Contract with Customer [Text Block]
Entity Address, Postal Zip Code
Derivative [Table]
Title of 12(b) Security
Security Exchange Name
Due after five years through ten years, Fair Value
Trading Symbol
Due after ten years, Fair Value
Due in one year or less, Fair Value
Due after one year through five years, Fair Value
Equity Lines Portfolio Segment [Member]
Loan based on the equity of the borrower's residential property in which the borrower receives the loan amount upfront.
Due after ten years, Amortized Cost
Class of Stock [Axis]
Advances from Federal Home Loan Bank
us-gaap_InterestExpenseFederalHomeLoanBankAndFederalReserveBankAdvancesLongTerm
Real Estate Construction Portfolio Segment [Member]
A borrowing arrangement which provides the entity constructing a facility (such as a building and a landfill) with funds to effect construction, generally on a draw down, or as needed, basis.
Public Deposits and Other Borrowings [Member]
Represents public deposits and other borrowings.
Foreign Exchange Contract [Member]
Entity Common Stock, Shares Outstanding
Interest Rate Contract [Member]
Other Comprehensive Income, net of tax
Earnings Per Share [Text Block]
Cash Flow Hedging [Member]
Hedging Designation [Axis]
Fair Value Hedging [Member]
Financing Receivable, Credit Quality Indicator [Table]
Loans held for investment
Internal Credit Assessment [Axis]
Net holding gains on securities available-for-sale
Short-term debt
us-gaap_InterestExpenseOtherLongTermDebt
Long-term debt
us-gaap_AvailableforsaleSecuritiesSoldAtPar
Debt Securities, Available-for-Sale, Sold at Par Value
Not Designated as Hedging Instrument [Member]
us-gaap_InterestExpenseOtherDomesticDeposits
Other deposits
us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss
Net interest income after provision for credit losses
Average Common Shares Outstanding:
Investments Classified by Contractual Maturity Date [Table Text Block]
Loan Held for Investment by Loan Portfolio Segments, Internal Risk Ratings and Vintage Year [Table Text Block]
Tabular disclosure of loan held for investment by loan portfolio segments, internal risk ratings and vintage year.
Deposits with banks
Internal Credit Assessment [Domain]
Short-term investments and interest-bearing deposits
Short-term investments and interest bearing deposits
Common stock, par value (in dollars per share)
Investment securities
caty_DividendIncomeFromFederalHomeLoanBankStock
Federal Home Loan Bank stock
Dividend income from Federal Home Loan Bank stock
Letters of credit commissions
Commissions revenue earned from letter of credit international services
Northern California 1 [Member]
Represents the geographical location of Northern California.
Other liabilities
Southern California1 [Member]
The geographical region of Southern California.
Hedging Relationship [Axis]
caty_PerformanceBasedRestrictedStockUnitsNumberOfSharesThatMayVestPercentageOfTarget
Performance-based Restricted Stock Units, Number of Shares That May Vest, Percentage of Target
Represents the number of performance-based restricted stock units that may vest, expressed as a percentage of the target.
Derivative Contract [Domain]
Net change in unrealized holding gain on securities available-for-sale, net of tax
Net change in unrealized holding (loss)/gain on securities available-for-sale, net of tax
Transfers to other real estate owned from loans held-for-investment
Transfers To Other Real Estate Owned From Loans Held For Investment
caty_NumberOfLimitedPartnershipsInHousingInvestments
Number Of Limited Partnerships In Housing Investments
Number of limited Partnerships in housing investments.
caty_NumberOfBranchLocations
Number Of Branch Locations
Number of branch locations
Cash and due from banks
us-gaap_Assets
Total assets
Residential Mortgage and Equity Lines Portfolio Segment [Member]
Residential mortgage segment is any loan primarily for personal, family, or household use that is secured by a mortgage, deed of trust, or other equivalent consensual security interest while Equity line portfolio segment loan based on the equity of the borrower's residential property in which the borrower receives the loan amount upfront.
Designated as Hedging Instrument [Member]
Financing Receivable, Nonaccrual [Table]
Geographical [Domain]
Geographical [Axis]
Amortization of investments in low-income housing and alternative energy partnerships
The amount of expense associated with the operations of affordable housing investments, net and alternative energy partnerships, net.
Modified
us-gaap_FinancingReceivableExcludingAccruedInterestModifiedIncreaseDecreaseFromModification
Modified
Modification as a % of total loans
Diluted (in dollars per share)
us-gaap_EarningsPerShareDiluted
Investment [Text Block]
caty_PercentageOfChargeOffToContractualBalancesForImpairedLoans
Percentage Of Charge Off To Contractual Balances For Impaired Loans
Percentage of charge-off to contractual balances for impaired loans.
Modified, subsequent default
Financing Receivable, Excluding Accrued Interest, Modified, Subsequent Default
Weighted average rate reduction
Financing Receivable, Modified, Past Due [Table]
us-gaap_DepreciationDepletionAndAmortization
Depreciation and amortization
Interest rate swaps, fair value
us-gaap_InterestRateDerivativeAssetsAtFairValue
Interest rate swaps
Asset Class [Domain]
us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation
Share-Based Payment Arrangement, Decrease for Tax Withholding Obligation
settlement of RSUs
Reduction of Interest Rate and Change in Payment Terms [Member]
Represents reduction of interest rate and change in payment terms.
Weighted average term increase (Year)
caty_InvestmentsInAffordableHousingAndAlternativeEnergyPartnerships
Investments in Affordable Housing and Alternative Energy Partnerships
The amount of investments in affordable housing and alternative energy partnerships.
Accounts and Financing Receivables [Table]
Investment Type [Axis]
Derivative assets, net amount
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]
Derivative liabilties, net amount
Interest rate swaps, fair value
us-gaap_InterestRateDerivativeLiabilitiesAtFairValue
Interest rate swaps
Accrued interest receivable
Interest
Interest Rate Swap [Member]
Intangible Asset, Finite-Lived [Table Text Block]
Intangible Asset, Finite-Lived [Table]
caty_EstimatedSalesCostAppliedToCollateral
Estimated Sales Cost Applied To Collateral
No authoritative reference available.
Years prior, write offs
Revolving, write offs
Three years prior, write offs
Four years prior, write offs
Prior year, write offs
Two years prior, write offs
Foreign exchange contracts with gain
caty_NotionalAmountOfForeignCurrencyDerivativePurchaseContractsWithGain
Notional amount of foreign currency derivative purchase contracts with gain.
Current year, write offs
Foreign exchange contracts with gain, fair value
caty_ForeignExchangeContractAssetFairValueGainDisclosure
Foreign exchange contract asset fair value gain disclosure.
us-gaap_SecuritiesSoldUnderAgreementsToRepurchase
Securities Sold under Agreements to Repurchase
Foreign exchange contracts with loss
caty_NotionalAmountOfForeignCurrencyDerivativePurchaseContractsWithLoss
Notional amount of foreign currency derivative purchase contracts with loss.
Foreign exchange contracts with loss, fair value
caty_ForeignCurrencyContractAssetFairValueLossDisclosure
Foreign currency contract asset fair value loss disclosure.
Commitments to extend credit
caty_CommitmentsToExtendNotionalAmount
Commitments To Extend Notional Amount
Commitments To Extend Notional Amount
us-gaap_HedgedAssetFairValueHedge
Hedged Asset, Fair Value Hedge
Hedging Relationship [Domain]
Converted to term, write offs
Commitments to extend credit, fair value
caty_CommitmentsToExtendCreditFairValue
Commitments to Extend Credit, Fair Value
Standby letters of credit
caty_StandbyLettersOfCreditNotionalAmount
Standby Letters Of Credit Notional Amount
Standby letters of credit, fair value
caty_StandbyLettersOfCreditFairValue
Standby Letters of Credit, Fair Value
Other letters of credit
caty_OtherLettersOfCreditNotionalAmount
Other Letters Of Credit Notional Amount
us-gaap_StockholdersEquity
Equity, Attributable to Parent
Total stockholders' equity
Beginning balance, loss, net of tax
Beginning balance, loss, net of tax
Other letters of credit, fair value
caty_OtherLettersOfCreditFairValue
Other Letters of Credit, Fair Value
Forfeited, weighted-average grant date fair value (in dollars per share)
Schedule Of Fair Value Of Financial Instruments [Table Text Block]
Schedule of Fair Value of Financial Instruments.
us-gaap_PaymentsOfDividends
Cash dividends paid
Derivative assets, gross amounts offset
Consolidation, Less-than-Wholly-Owned Subsidiary, Parent Ownership Interest, Effect of Change [Table]
Right-of-use assets - operating leases
us-gaap_RepaymentsOfFederalHomeLoanBankBorrowings
Repayment of Federal Home Loan Bank borrowings
us-gaap_DebtSecuritiesAvailableForSaleAccruedInterestAfterAllowanceForCreditLoss
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss
ecd_Rule10b51ArrTrmntdFlag
Rule 10b5-1 Arrangement Terminated [Flag]
us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Non-Interest Income
ecd_Rule10b51ArrAdoptedFlag
Rule 10b5-1 Arrangement Adopted [Flag]
us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax
Revenues
Asset Management [Member]
Commitments and contingencies
Derivative liabilities, gross amounts offset