NON COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES, Restructured Loans (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Restructured Loans [Abstract]
Amount of restructured loans that are performing according to new terms and conditions	$ 60.1	$ 122.1
Amount of nonperforming restructured loans that are on nonaccrual status	$ 11.9	$ 42.1

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ewbc_FinancingReceivableRestructuredRecordedInvestmentNonperforming

Namespace Prefix:

ewbc

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xbrli:monetaryItemType

Balance Type:

debit

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instant