XML 73 R53.htm IDEA: XBRL DOCUMENT
v2.4.1.9

SUMMARY OF OPERATIONS AND SIGNIFICANT ACCOUNTING POLICIES (Details) | 12 Months Ended
--- | ---
Dec. 31, 2014 item trust | Dec. 31, 2013 | Dec. 31, 2012
Operations summary |  |  |
Number of banking locations | 130 ewbc_NumberOfBankingLocations |  |
Principles of Consolidation |  |  |
Number of wholly owned subsidiaries that are statutory business trusts ("the Trusts") | 6 ewbc_NumberOfWhollyOwnedStatutoryBusinessTrusts |  |
Cash and Cash Equivalents |  |  |
Minimum term of cash and cash equivalients investments | 1 day |  |
Maximum term of cash and cash equivalients investments | 90 days |  |
Short-term investments |  |  |
Minimum term of maturities of other short-term investments | 90 days |  |
Maximum term of maturities of other short-term investments | 1 year |  |
Securities purchased under resale agreements ("Resale Agreements") |  |  |
Minimum term of resale agreement to be classified as cash and cash equivalents | 1 day |  |
Maximum term of resale agreement to be classified as cash and cash equivalents | 90 days |  |
Loans receivable |  |  |
Number of past due days for the loans receivable to be placed on nonaccrual status | 90 days |  |
Troubled debt restructurings |  |  |
Period for which restructured loans remains on nonaccrual status, to demonstrate that the borrower can perform under the restructured terms | 6 months |  |
Other real estate owned |  |  |
Maximum period of foreclosure within which sale of real estate owned will be recorded at fair value less cost of sales | 3 months |  |
FDIC percentage of reimbursement under shared loss agreements |  |  |
FDIC percentage of reimbursement under shared loss agreements | 80.00%ewbc_PercentageOfEligibleLossesForWhichFdicIsObligatedToReimburse | 80.00%ewbc_PercentageOfEligibleLossesForWhichFdicIsObligatedToReimburse | 80.00%ewbc_PercentageOfEligibleLossesForWhichFdicIsObligatedToReimburse
Percentage of company's liability for losses under shared loss agreements. | 20.00%ewbc_PercentageOfCompanysLiabilityForLossesUnderSharedLossAgreements | 20.00%ewbc_PercentageOfCompanysLiabilityForLossesUnderSharedLossAgreements | 20.00%ewbc_PercentageOfCompanysLiabilityForLossesUnderSharedLossAgreements
Greater China |  |  |
Operations summary |  |  |
Number of full-service branches | 5 ewbc_NumberOfFullServiceBranches / dei_EntityByLocationAxis = country_CN |  |
Number of representative offices | 5 ewbc_NumberOfRepresentativeOffices / dei_EntityByLocationAxis = country_CN |  |
Shanghai |  |  |
Operations summary |  |  |
Number of full-service branches | 2 ewbc_NumberOfFullServiceBranches / dei_EntityByLocationAxis = ewbc_ShanghaiMember |  |
Shanghai Pilot Free Trade Zone |  |  |
Operations summary |  |  |
Number of full-service branches | 1 ewbc_NumberOfFullServiceBranches / dei_EntityByLocationAxis = ewbc_ShanghaiPilotFreeTradeZoneMember |  |

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

X
- Definition Represents the maximum term of cash and cash equivalents investments. + References No definition available. + Details
Name: | ewbc_CashAndCashEquivalentsInvestmentsMaximum
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the minimum term of cash and cash equivalents investments. + References No definition available. + Details
Name: | ewbc_CashAndCashEquivalentsInvestmentsMinimum
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of consecutive months of payments received from the borrower on a nonperforming restructured loan for it to be considered as demonstrating a sustained period of performance and be removed from nonaccrual status. + References No definition available. + Details
Name: | ewbc_FinancingReceivableNumberOfPaymentMonthsConsideredSustainedPeriodOfPerformance
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of past due days for the loans receivable to be placed on nonaccrual status. + References No definition available. + Details
Name: | ewbc_LoansReceivableNonAccrualStatusNumberOfPastDueDays
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of banking locations in which the entity operates. + References No definition available. + Details
Name: | ewbc_NumberOfBankingLocations
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of full-service branches of the entity. + References No definition available. + Details
Name: | ewbc_NumberOfFullServiceBranches
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of representative offices of the entity. + References No definition available. + Details
Name: | ewbc_NumberOfRepresentativeOffices
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of wholly owned subsidiaries of the entity that are statutory business trusts, which are not consolidated. + References No definition available. + Details
Name: | ewbc_NumberOfWhollyOwnedStatutoryBusinessTrusts
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition The percentage of losses related to other real estate owned for which the company retains liability. + References No definition available. + Details
Name: | ewbc_PercentageOfCompanysLiabilityForLossesUnderSharedLossAgreements
Namespace Prefix: | ewbc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of eligible losses for which the FDIC is obligated to reimburse the Company pursuant to the shared-loss agreements. + References No definition available. + Details
Name: | ewbc_PercentageOfEligibleLossesForWhichFdicIsObligatedToReimburse
Namespace Prefix: | ewbc_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

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

X
- Definition Represents the maximum period of foreclosure within which sale of real estate owned will be recorded at fair value (less cost of sales). + References No definition available. + Details
Name: | ewbc_RealEstateOwnedMaximumForeclosurePeriodWithinWhichSaleIsRecognizedAtFairValue
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the maximum term of resale agreement to be classified as cash and cash equivalents. + References No definition available. + Details
Name: | ewbc_ResaleAgreementMaximumTermToBeClassifiedAsCashAndCashEquivalents
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the minimum term of resale agreement to be classified as cash and cash equivalents. + References No definition available. + Details
Name: | ewbc_ResaleAgreementMinimumTermToBeClassifiedAsCashAndCashEquivalents
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Represents the maximum term of other short-term investments to be classified as cash and cash equivalents. + References No definition available. + Details
Name: | ewbc_ShortTermInvestmentsMaximum
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the minimum term of other short-term investments to be classified as cash and cash equivalents. + References No definition available. + Details
Name: | ewbc_ShortTermInvestmentsMinimum
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_CashAndCashEquivalentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DisclosureOfResaleAgreementsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_LoansReceivableNetAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_OtherRealEstateAndForeclosedAssetsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ShortTermInvestmentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | dei_EntityByLocationAxis=country_CN
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_EntityByLocationAxis=ewbc_ShanghaiMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_EntityByLocationAxis=ewbc_ShanghaiPilotFreeTradeZoneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |