Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 12A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481933/310-10-55-12A

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 34
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-34

Reference 3: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 33
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-33

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-42

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 42
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-42

+ Details

Name:	us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of decrease in weighted average contractual interest rate of financing receivable modified for debtor experiencing financial difficulty.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModifiedWeightedAverageInterestRateDecreaseFromModification
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period of increase in weighted average maturity 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.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModifiedWeightedAverageTermIncreaseFromModification
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ewbc_CommercialAndIndustrialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_InterestRateBelowMarketReductionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_ExtendedMaturityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LoanRestructuringModificationAxis=us-gaap_PaymentDeferralMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=srt_SingleFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ewbc_OtherConsumerMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loans Receivable and Allowance for Credit Losses - Schedule Of Financial Effects of Loan Modifications (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Commercial lending \| C&I \| Weighted-Average Interest Rate Reduction
Loans Modified
Weighted-Average Interest Rate Reduction	3.38%	0.00%	3.38%	0.00%
Commercial lending \| C&I \| Weighted-Average Term Extension (in years)
Loans Modified
Weighted average of loans (in years)	10 months 24 days	2 years	1 year	2 years
Commercial lending \| C&I \| Weighted-Average Payment Delay (in years)
Loans Modified
Weighted average of loans (in years)	8 months 12 days	2 years	9 months 18 days	1 year 6 months
Commercial lending \| CRE \| Weighted-Average Interest Rate Reduction
Loans Modified
Weighted-Average Interest Rate Reduction	0.00%	2.50%	0.00%	2.66%
Commercial lending \| CRE \| Weighted-Average Term Extension (in years)
Loans Modified
Weighted average of loans (in years)	2 years 9 months 18 days	0 years	3 years	1 year 6 months
Commercial lending \| CRE \| Weighted-Average Payment Delay (in years)
Loans Modified
Weighted average of loans (in years)	0 years	1 year 2 months 12 days	0 years	1 year
Consumer lending \| Single-family residential \| Weighted-Average Interest Rate Reduction
Loans Modified
Weighted-Average Interest Rate Reduction	0.00%	0.00%	0.00%	0.00%
Consumer lending \| Single-family residential \| Weighted-Average Term Extension (in years)
Loans Modified
Weighted average of loans (in years)	10 years	0 years	10 years	0 years
Consumer lending \| Single-family residential \| Weighted-Average Payment Delay (in years)
Loans Modified
Weighted average of loans (in years)	1 year 10 months 24 days	9 months 18 days	1 year 6 months	9 months 18 days
Consumer lending \| HELOCs \| Weighted-Average Interest Rate Reduction
Loans Modified
Weighted-Average Interest Rate Reduction	0.50%	0.00%	0.50%	0.25%
Consumer lending \| HELOCs \| Weighted-Average Term Extension (in years)
Loans Modified
Weighted average of loans (in years)	10 years	0 years	15 years 2 months 12 days	0 years
Consumer lending \| HELOCs \| Weighted-Average Payment Delay (in years)
Loans Modified
Weighted average of loans (in years)	5 years 1 month 6 days	8 months 12 days	8 years	2 years 9 months 18 days
Consumer lending \| Other consumer \| Weighted-Average Interest Rate Reduction
Loans Modified
Weighted-Average Interest Rate Reduction	0.00%	0.00%	0.00%	0.00%
Consumer lending \| Other consumer \| Weighted-Average Term Extension (in years)
Loans Modified
Weighted average of loans (in years)	0 years	9 months 18 days	0 years	9 months 18 days
Consumer lending \| Other consumer \| Weighted-Average Payment Delay (in years)
Loans Modified
Weighted average of loans (in years)	0 years	0 years	0 years	0 years