XML 112 R96.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Investments in Qualified Affordable Housing Partnerships, Tax Credit and Other Investments, Net (Investments in Tax Credit and Other Investments, Net) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
INVESTMENTS IN QUALIFIED AFFORDABLE HOUSING PARTNERSHIPS, TAX CREDIT AND OTHER INVESTMENTS, NET |  |  |
Minimum compliance period to fully utilize the tax credits | 15 years |  |
Investments in tax credit investments, net | $ 224,551 | $ 173,280 |
Schedule of Equity Method Investments [Line Items] |  |  |
Amortization of tax credit and other investments | 87,950 | 83,446 | $ 36,120
Accrued Expenses and Other Liabilities |  |  |
Schedule of Equity Method Investments [Line Items] |  |  |
Commitments for other tax credit investments | $ 113,400 | $ 117,000 |

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

X
- Definition Represents the net amount of investments in the projects, excluding affordable housing projects, that qualify for Community Reinvestment Act (CRA) credits or other types of tax credits. + References No definition available. + Details
Name: | ewbc_InvestmentsinTaxCreditandOtherInvestments
Namespace Prefix: | ewbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the minimum compliance period, to meet regulatory requirements for affordable housing, to fully utilize the tax credits. + References No definition available. + Details
Name: | ewbc_MinimumCompliancePeriodToFullyUtilizeTaxCredits
Namespace Prefix: | ewbc_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amortization of investments in projects that qualify for Community Reinvestment Act ("CRA") and other tax credits, included as a component of noninterest expense. + References No definition available. + Details
Name: | ewbc_NoninterestExpenseAmortizationOfTaxCreditInvestments
Namespace Prefix: | ewbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of commitment or contingent commitments to investments in certain limited partnerships that qualify for Community Reinvestment Act (CRA) credits or other types of tax credits. + References No definition available. + Details
Name: | ewbc_OtherTaxCreditInvestmentsCommitment
Namespace Prefix: | ewbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=ewbc_AccruedExpensesAndOtherLiabilitiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |