XML 72 R55.htm IDEA: XBRL DOCUMENT
v3.23.1

Securities - Scheduled Contractual Maturities of HTM Debt Securities (Details) $ in Thousands | Mar. 31, 2023 USD ($)
--- | ---
Amortized cost |
Within One Year | $ 0
After One Year through Five Years | 525,432
After Five Years through Ten Years | 375,982
After Ten Years | 2,092,007
Total | 2,993,421
Fair value |
Within One Year | 0
After One Year through Five Years | 481,611
After Five Years through Ten Years | 322,388
After Ten Years | 1,698,675
Total | $ 2,502,674
Weighted Average Yield |
Within One Year | 0.00%
After One Year through Five Years | 1.05%
After Five Years through Ten Years | 1.83%
After Ten Years | 1.77%
Total | 1.65%
U.S. Treasury securities |
Amortized cost |
Within One Year | $ 0
After One Year through Five Years | 525,432
After Five Years through Ten Years | 0
After Ten Years | 0
Total | 525,432
Fair value |
Within One Year | 0
After One Year through Five Years | 481,611
After Five Years through Ten Years | 0
After Ten Years | 0
Total | $ 481,611
Weighted Average Yield |
Within One Year | 0.00%
After One Year through Five Years | 1.05%
After Five Years through Ten Years | 0.00%
After Ten Years | 0.00%
Total | 1.05%
U.S. government-sponsored enterprises debt securities |
Amortized cost |
Within One Year | $ 0
After One Year through Five Years | 0
After Five Years through Ten Years | 280,289
After Ten Years | 719,566
Total | 999,855
Fair value |
Within One Year | 0
After One Year through Five Years | 0
After Five Years through Ten Years | 240,780
After Ten Years | 565,561
Total | $ 806,341
Weighted Average Yield |
Within One Year | 0.00%
After One Year through Five Years | 0.00%
After Five Years through Ten Years | 1.92%
After Ten Years | 1.89%
Total | 1.90%
U.S. government agency and U.S. government sponsored enterprise mortgage-backed securities |
Amortized cost |
Within One Year | $ 0
After One Year through Five Years | 0
After Five Years through Ten Years | 95,693
After Ten Years | 1,182,934
Total | 1,278,627
Fair value |
Within One Year | 0
After One Year through Five Years | 0
After Five Years through Ten Years | 81,608
After Ten Years | 978,518
Total | $ 1,060,126
Weighted Average Yield |
Within One Year | 0.00%
After One Year through Five Years | 0.00%
After Five Years through Ten Years | 1.56%
After Ten Years | 1.67%
Total | 1.66%
Municipal securities |
Amortized cost |
Within One Year | $ 0
After One Year through Five Years | 0
After Five Years through Ten Years | 0
After Ten Years | 189,507
Total | 189,507
Fair value |
Within One Year | 0
After One Year through Five Years | 0
After Five Years through Ten Years | 0
After Ten Years | 154,596
Total | $ 154,596
Weighted Average Yield |
Within One Year | 0.00%
After One Year through Five Years | 0.00%
After Five Years through Ten Years | 0.00%
After Ten Years | 1.98%
Total | 1.98%

X
- Definition Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAfterYear10
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAfterYear5Through10
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateAfterYearOneThroughFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount excluding accrued interest, after allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity) with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostExcludingAccruedInterestAfterAllowanceForCreditLossMaturityAllocatedAndSingleMaturityDateYearOne
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity) maturing after tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1403 -Paragraph (a) -Subparagraph (4) -Publisher SEC Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name Industry Guide -Number 3 -Section II -Paragraph B -Publisher SEC + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityMaturityAfter10YearsWeightedAverageYield
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity) maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1403 -Paragraph (a) -Subparagraph (3) -Publisher SEC Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name Industry Guide -Number 3 -Section II -Paragraph B -Publisher SEC + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityMaturityAfterFiveThroughTenYearsWeightedAverageYield
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity) maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1403 -Paragraph (a) -Subparagraph (2) -Publisher SEC Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name Industry Guide -Number 3 -Section II -Paragraph B -Publisher SEC + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityMaturityAfterOneThroughFiveYearsWeightedAverageYield
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityMaturityWeightedAverageYieldAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity) maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1403 -Paragraph (a) -Subparagraph (1) -Publisher SEC Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Name Industry Guide -Number 3 -Section II -Paragraph B -Publisher SEC + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityMaturityWithinOneYearWeightedAverageYield
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted average yield of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Name Regulation S-K (SK) -Number 229 -Section 1403 -Paragraph (a) -Publisher SEC + Details
Name: | us-gaap_DebtSecuritiesHeldToMaturityWeightedAverageYield
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5B Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3A Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(3) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in second through fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5B Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3A Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing after tenth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5B Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3A Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5B Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3A Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesSingleMaturityDateFairValueAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of investment in debt security measured at amortized cost (held-to-maturity), with single maturity date and allocated without single maturity date, maturing in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5B Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3A Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 5 -Subparagraph (f)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-5 Reference 4: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 942 -SubTopic 320 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480832/942-320-50-3 + Details
Name: | us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

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

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

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