COMMITMENTS AND CONTINGENCIES (Details) (USD $) In Billions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Undisbursed Loan Commitments
Credit Extensions
Loan	$ 4.34	$ 4.02
Commercial and Standby Letters of Credit
Credit Extensions
Commercial and standby letters of credit issued	$ 1.17	$ 1.16

Reflects the amount of cash required to fully fund agreements to provide advances to borrowers and lessees at fixed and variable interest rates.

No definition available.

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