XML 22 R121.htm IDEA: XBRL DOCUMENT
v2.4.0.6

SEGMENT INFORMATION (Details) | 3 Months Ended |  |
--- | --- | --- | ---
Mar. 31, 2010 Segment | Mar. 31, 2009 Segment | Dec. 31, 2011 Segment | Nov. 30, 2009 Segment
SEGMENT INFORMATION |  |  |  |
Number of operating segments | 3 |  | 3 | 4
Number of business divisions | 3 | 3 | 3 |
Number of segments combined |  | 2 |  |
Number of core business segment in which the UCB segment is combined | 2 |  |  |
Number of segment whom broad administrative support are provided |  |  | 2 |

X
- Definition The total number of business divisions that meet the criteria of an operating segment. + References No definition available. + Details
Name: | ewbc_NumberOfBusinessDivisions
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of core business segment in which the specified segment is combined by the company. + References No definition available. + Details
Name: | ewbc_NumberOfCoreSegmentsInWhichSpecifiedSegmentCombined
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition The total number of operating segments for the company. + References No definition available. + Details
Name: | ewbc_NumberOfOperatingSegments
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the number of segments combined due to the consumer-centric nature of the product and service offered by the segments. + References No definition available. + Details
Name: | ewbc_NumberOfOperatingSegmentsCombined
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of segments that are provided broad administrative support. + References No definition available. + Details
Name: | ewbc_NumberOfSegmentWhomBroadAdministrativeSupportProvided
Namespace Prefix: | ewbc_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | instant

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