NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 10) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Performing loan
Restructured loans disclosures
Allowance for troubled debt restructurings loans receivable	$ 7,400	$ 8,700
Nonperforming loan
Restructured loans disclosures
Allowance for troubled debt restructurings loans receivable	$ 517	$ 203

The reserve to cover probable credit losses related to financing receivables that have been modified by troubled debt restructurings.

No definition available.

Name:	ewbc_AllowanceForTroubledDebtRestructuringsLoansReceivable
Namespace Prefix:	ewbc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant