Name:	ewbc_ProceedsFromSaleOfLoansHeldForSaleAndReclassified
Namespace Prefix:	ewbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The write-down of loans transferred from loans held for investment to loans held for sale recorded to allowance for loan losses.

No definition available.

Name:	ewbc_WriteDownsOnLoansHeldForSale
Namespace Prefix:	ewbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans and leases that were sold during the reporting period. This element refers to the gain (loss) and not to the cash proceeds of the sales. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount classified as loans attributable to disposal group held for sale or disposed of. Excludes loans and leases covered under loss sharing agreements and loans classified as debt securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Name:	us-gaap_LoansReceivableHeldForSaleNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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

Value of loans and leases held in the entity's portfolio transferred to loans and leases held-for-sale in noncash transactions.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4332-108586

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