XML 105 R84.htm IDEA: XBRL DOCUMENT
v2.4.1.9

Note 10 - Borrowed Funds (Details) (USD $) | 1 Months Ended | 10 Months Ended | 12 Months Ended
--- | --- | --- | ---
Dec. 31, 2014 | Dec. 31, 2014 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2005 | Dec. 31, 2004
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Securities Sold under Agreements to Repurchase | $ 450,000,000 us-gaap_SecuritiesSoldUnderAgreementsToRepurchase | $ 450,000,000 us-gaap_SecuritiesSoldUnderAgreementsToRepurchase | $ 450,000,000 us-gaap_SecuritiesSoldUnderAgreementsToRepurchase | $ 800,000,000 us-gaap_SecuritiesSoldUnderAgreementsToRepurchase |  |  |
Weighted Average Rate Of Securities Sold Under Agreements | 3.85%caty_WeightedAverageRateOfSecuritiesSoldUnderAgreements | 3.85%caty_WeightedAverageRateOfSecuritiesSoldUnderAgreements | 3.85%caty_WeightedAverageRateOfSecuritiesSoldUnderAgreements | 3.87%caty_WeightedAverageRateOfSecuritiesSoldUnderAgreements |  |  |
Prepaid Security Sold Under Repurchase Agreement | 100,000,000 caty_PrepaidSecuritySoldUnderRepurchaseAgreement | 100,000,000 caty_PrepaidSecuritySoldUnderRepurchaseAgreement | 100,000,000 caty_PrepaidSecuritySoldUnderRepurchaseAgreement | 450,000,000 caty_PrepaidSecuritySoldUnderRepurchaseAgreement |  |  |
Rate of Prepaid Security Sold Under Repurchase Agreements | 3.50%caty_RateOfPrepaidSecuritySoldUnderRepurchaseAgreements | 3.50%caty_RateOfPrepaidSecuritySoldUnderRepurchaseAgreements | 3.50%caty_RateOfPrepaidSecuritySoldUnderRepurchaseAgreements | 3.79%caty_RateOfPrepaidSecuritySoldUnderRepurchaseAgreements |  |  |
Prepayment Penalty Security Sold Under Agreements to Repurchase | 3,400,000 caty_PrepaymentPenaltySecuritySoldUnderAgreementsToRepurchase | 3,400,000 caty_PrepaymentPenaltySecuritySoldUnderAgreementsToRepurchase | 3,400,000 caty_PrepaymentPenaltySecuritySoldUnderAgreementsToRepurchase | 22,600,000 caty_PrepaymentPenaltySecuritySoldUnderAgreementsToRepurchase |  |  |
Debt Instrument, Basis Spread on Variable Rate |  | 3.50%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage | 8.00%us-gaap_DebtInstrumentInterestRateStatedPercentage | 8.00%us-gaap_DebtInstrumentInterestRateStatedPercentage | 8.00%us-gaap_DebtInstrumentInterestRateStatedPercentage |  |  |  |
Advances from Federal Home Loan Banks | 425,000,000 us-gaap_AdvancesFromFederalHomeLoanBanks | 425,000,000 us-gaap_AdvancesFromFederalHomeLoanBanks | 425,000,000 us-gaap_AdvancesFromFederalHomeLoanBanks | 521,200,000 us-gaap_AdvancesFromFederalHomeLoanBanks |  |  |
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Weighted Average Interest Rate | 0.32%us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankWeightedAverageInterestRate | 0.32%us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankWeightedAverageInterestRate | 0.32%us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankWeightedAverageInterestRate | 0.17%us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankWeightedAverageInterestRate |  |  |
Federal Home Loan Bank Prepaid Advances |  |  | 171,200,000 caty_FederalHomeLoanBankPrepaidAdvances | 0 caty_FederalHomeLoanBankPrepaidAdvances |  |  |
Weighted Average Rate for Prepaying Federal Home Loan Bank Advances | 1.08%caty_WeightedAverageRateForPrepayingFederalHomeLoanBankAdvances | 1.08%caty_WeightedAverageRateForPrepayingFederalHomeLoanBankAdvances | 1.08%caty_WeightedAverageRateForPrepayingFederalHomeLoanBankAdvances |  |  |  |
Prepayment Fees on Advances, Net |  |  | 527,000 us-gaap_PrepaymentFeesOnAdvancesNet | 0 us-gaap_PrepaymentFeesOnAdvancesNet |  |  |
Threshold for Deferred Bonus |  |  |  |  |  | 225,000 caty_ThresholdForDeferredBonus |
Amount of Deferred Bonus Accrued in Other Liabilities |  |  | 300,000 caty_AmountOfDeferredBonusAccruedInOtherLiabilities |  |  |  | 610,000 caty_AmountOfDeferredBonusAccruedInOtherLiabilities
Accrued Interest on Deferred Bonus | 5.06%caty_AccruedInterestOnDeferredBonus | 5.02%caty_AccruedInterestOnDeferredBonus |  |  |  |  | 7.00%caty_AccruedInterestOnDeferredBonus
Debt Instrument Basis Spread on Variable Rate 2 | 2.75%caty_DebtInstrumentBasisSpreadOnVariableRate2 | 2.75%caty_DebtInstrumentBasisSpreadOnVariableRate2 | 2.75%caty_DebtInstrumentBasisSpreadOnVariableRate2 |  |  |  |
Interest Expense, Other |  |  | 93,000 us-gaap_InterestExpenseOther | 77,000 us-gaap_InterestExpenseOther | 71,000 us-gaap_InterestExpenseOther |  |
Accrued Bonuses | 1,500,000 us-gaap_AccruedBonusesCurrentAndNoncurrent | 1,500,000 us-gaap_AccruedBonusesCurrentAndNoncurrent | 1,500,000 us-gaap_AccruedBonusesCurrentAndNoncurrent | 1,100,000 us-gaap_AccruedBonusesCurrentAndNoncurrent |  |  |
Callable Securities [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Securities Sold under Agreements to Repurchase | 250,000,000 us-gaap_SecuritiesSoldUnderAgreementsToRepurchase / us-gaap_FinancialInstrumentAxis = caty_CallableSecuritiesMember | 250,000,000 us-gaap_SecuritiesSoldUnderAgreementsToRepurchase / us-gaap_FinancialInstrumentAxis = caty_CallableSecuritiesMember | 250,000,000 us-gaap_SecuritiesSoldUnderAgreementsToRepurchase / us-gaap_FinancialInstrumentAxis = caty_CallableSecuritiesMember |  |  |  |
Floating to Fixed Rate Agreements Totaling $200 Million [Member] | London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  | 3.40%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember |  |  |  |
Floating to Fixed Rate Agreements Totaling $200 Million [Member] | Maximum [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage | 5.07%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember / us-gaap_RangeAxis = us-gaap_MaximumMember | 5.07%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember / us-gaap_RangeAxis = us-gaap_MaximumMember | 5.07%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember / us-gaap_RangeAxis = us-gaap_MaximumMember |  |  |  |
Floating to Fixed Rate Agreements Totaling $200 Million [Member] | Minimum [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage | 4.89%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember / us-gaap_RangeAxis = us-gaap_MinimumMember | 4.89%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember / us-gaap_RangeAxis = us-gaap_MinimumMember | 4.89%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember / us-gaap_RangeAxis = us-gaap_MinimumMember |  |  |  |
Floating to Fixed Rate Agreements Totaling $200 Million [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Number of Floating-to-fixed Rate Agreements | 4 caty_NumberOfFloatingToFixedRateAgreements / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember | 4 caty_NumberOfFloatingToFixedRateAgreements / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember | 4 caty_NumberOfFloatingToFixedRateAgreements / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember |  |  |  |
Total Floating to Fixed Rate | 200,000,000 caty_TotalFloatingToFixedRate / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember | 200,000,000 caty_TotalFloatingToFixedRate / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember | 200,000,000 caty_TotalFloatingToFixedRate / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementsTotaling200MillionMember |  |  |  |
Floating Interest Rate, Range of Time Period |  |  | 1 year |  |  |  |
Floating to Fixed Rate Agreement Totaling $50 Million [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Floating Interest Rate, Range of Time Period |  |  | 9 months |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage | 1.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember | 1.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember | 1.00%us-gaap_DebtInstrumentInterestRateStatedPercentage / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember |  |  |  |
Number of Fixed-to-floating Security Sold Under Agreements to Repurchase | 1 caty_NumberOfFixedToFloatingSecuritySoldUnderAgreementsToRepurchase / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember | 1 caty_NumberOfFixedToFloatingSecuritySoldUnderAgreementsToRepurchase / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember | 1 caty_NumberOfFixedToFloatingSecuritySoldUnderAgreementsToRepurchase / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember |  |  |  |
Total Fixed to Floating Rate Agreements | 50,000,000 caty_TotalFixedToFloatingRateAgreements / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember | 50,000,000 caty_TotalFixedToFloatingRateAgreements / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember | 50,000,000 caty_TotalFixedToFloatingRateAgreements / caty_FinancialInstrumentsOwnedAxis = caty_FloatingToFixedRateAgreementTotaling50MillionMember |  |  |  |
Securities Sold under Agreements to Repurchase [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Investment Securities Pledged As Collateral | $ 516,300,000 caty_InvestmentSecuritiesPledgedAsCollateral / caty_FinancialInstrumentsOwnedAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember | $ 516,300,000 caty_InvestmentSecuritiesPledgedAsCollateral / caty_FinancialInstrumentsOwnedAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember | $ 516,300,000 caty_InvestmentSecuritiesPledgedAsCollateral / caty_FinancialInstrumentsOwnedAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember | $ 906,100,000 caty_InvestmentSecuritiesPledgedAsCollateral / caty_FinancialInstrumentsOwnedAxis = us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember |  |  |
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Debt Instrument, Basis Spread on Variable Rate |  |  | 3.50%us-gaap_DebtInstrumentBasisSpreadOnVariableRate1 / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember |  |  |  |
London Interbank Offered Rate (LIBOR) [Member] |  |  |  |  |  |  |
Note 10 - Borrowed Funds (Details) [Line Items] |  |  |  |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum |  |  | 0.00%us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum / us-gaap_VariableRateAxis = us-gaap_LondonInterbankOfferedRateLIBORMember |  |  |  |

X
- Definition Accrued interest rate on deferred bonus. + References No definition available. + Details
Name: | caty_AccruedInterestOnDeferredBonus
Namespace Prefix: | caty_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the amount of deferred bonus accrued in other liabilities. + References No definition available. + Details
Name: | caty_AmountOfDeferredBonusAccruedInOtherLiabilities
Namespace Prefix: | caty_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage points subtracted from the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | caty_DebtInstrumentBasisSpreadOnVariableRate2
Namespace Prefix: | caty_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents federal home loan bank prepaid advances. + References No definition available. + Details
Name: | caty_FederalHomeLoanBankPrepaidAdvances
Namespace Prefix: | caty_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Floating Interest Rate, Range of Time Period + References No definition available. + Details
Name: | caty_FloatingInterestRateRangeofTimePeriod
Namespace Prefix: | caty_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Investment securities pledged as collateral. + References No definition available. + Details
Name: | caty_InvestmentSecuritiesPledgedAsCollateral
Namespace Prefix: | caty_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | caty_Note10BorrowedFundsDetailsLineItems
Namespace Prefix: | caty_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number Of Fixed-To-Floating Security Sold Under Agreements To Repurchase + References No definition available. + Details
Name: | caty_NumberOfFixedToFloatingSecuritySoldUnderAgreementsToRepurchase
Namespace Prefix: | caty_
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number Of Floating-To-Fixed Rate Agreements + References No definition available. + Details
Name: | caty_NumberOfFloatingToFixedRateAgreements
Namespace Prefix: | caty_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Prepaid Security Sold Under Repurchase Agreement + References No definition available. + Details
Name: | caty_PrepaidSecuritySoldUnderRepurchaseAgreement
Namespace Prefix: | caty_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Prepayment Penalty Security Sold Under Agreements To Repurchase + References No definition available. + Details
Name: | caty_PrepaymentPenaltySecuritySoldUnderAgreementsToRepurchase
Namespace Prefix: | caty_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition No authoritative reference available. + References No definition available. + Details
Name: | caty_RateOfPrepaidSecuritySoldUnderRepurchaseAgreements
Namespace Prefix: | caty_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the threshold for deferred bonus. + References No definition available. + Details
Name: | caty_ThresholdForDeferredBonus
Namespace Prefix: | caty_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Total Fixed To Floating Rate Agreements + References No definition available. + Details
Name: | caty_TotalFixedToFloatingRateAgreements
Namespace Prefix: | caty_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Total Floating To Fixed Rate + References No definition available. + Details
Name: | caty_TotalFloatingToFixedRate
Namespace Prefix: | caty_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the weighted average rate for prepaying federal home loan bank advances. + References No definition available. + Details
Name: | caty_WeightedAverageRateForPrepayingFederalHomeLoanBankAdvances
Namespace Prefix: | caty_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted Average Rate Of Securities Sold Under Agreements + References No definition available. + Details
Name: | caty_WeightedAverageRateOfSecuritiesSoldUnderAgreements
Namespace Prefix: | caty_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Carrying value as of the balance sheet date of obligations incurred and payable for incentive compensation awarded to employees and directors or earned by them based on the terms of one or more relevant arrangements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.15(5)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.15(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 15 -Subparagraph a -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 15 -Subparagraph 5 -Article 9 + Details
Name: | us-gaap_AccruedBonusesCurrentAndNoncurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 + Details
Name: | us-gaap_AdvancesFromFederalHomeLoanBanks
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Percentage points added to the reference rate to compute the variable rate on the debt instrument. + References No definition available. + Details
Name: | us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Minimum contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Describes the weighted average interest rate applicable to the specific advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6479118&loc=d3e64650-112822 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6479336&loc=d3e64711-112823 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Interest expense on all other items not previously classified. For example, includes dividends associated with redeemable preferred stock of a subsidiary that is treated as a liability in the parent's consolidated balance sheet. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4D -URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624177-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph -4 -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 + Details
Name: | us-gaap_InterestExpenseOther
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of income earned, after hedging basis adjustments, from fees charged for prepayment of certain Federal Home Loan Bank (FHLBank) advances before original maturity. + References No definition available. + Details
Name: | us-gaap_PrepaymentFeesOnAdvancesNet
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount, after the effects of master netting arrangements, of funds outstanding borrowed in the form of a security repurchase agreement between the entity and another party for the sale and repurchase of identical or substantially the same securities at a date certain for a specified price. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.13(1)) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=34720828&loc=SL20225862-175312 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=36459792&loc=SL20226008-175313 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 13 -Subparagraph 1 -Article 9 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=45278096&loc=d3e9760-107771 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(m)(1)(a)(i)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_SecuritiesSoldUnderAgreementsToRepurchase
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | caty_FinancialInstrumentsOwnedAxis=caty_FloatingToFixedRateAgreementsTotaling200MillionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | caty_FinancialInstrumentsOwnedAxis=caty_FloatingToFixedRateAgreementTotaling50MillionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | caty_FinancialInstrumentsOwnedAxis=us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=caty_CallableSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |