Credit risk adjustment rate used as an input to measure fair value.

No definition available.

Name:	ewbc_FairValueInputsCreditRiskAdjustmentRate
Namespace Prefix:	ewbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of likelihood the underlying collateral will not be repaid and instead default, used as an input to measure fair value after five years.

+ References

No definition available.

+ Details

Name:	ewbc_FairValueInputsDefaultRateAfterFiveYears
Namespace Prefix:	ewbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of likelihood the underlying collateral will not be repaid and instead default, used as an input to measure fair value for first five years.

+ References

No definition available.

+ Details

Name:	ewbc_FairValueInputsDefaultRateForFirstFiveYears
Namespace Prefix:	ewbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Rate at which the underlying collateral is expected to prepay, used as an input to measure fair value after five years.

+ References

No definition available.

+ Details

Name:	ewbc_FairValueInputsPrepaymentRateAfterFiveYears
Namespace Prefix:	ewbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Rate at which the underlying collateral is expected to prepay, used as an input to measure fair value for first five years.

+ References

No definition available.

+ Details

Name:	ewbc_FairValueInputsPrepaymentRateForFirstFiveYears
Namespace Prefix:	ewbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Period at which the underlying collateral is expected to recover, used as an input to measure fair value.

+ References

No definition available.

+ Details

Name:	ewbc_FairValueInputsRecoveryPeriodForFutureDeferral
Namespace Prefix:	ewbc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Rate at which the underlying collateral is expected to recover for the existing deferrals, used as an input to measure fair value.

+ References

No definition available.

+ Details

Name:	ewbc_FairValueInputsRecoveryRateForExistingDeferral
Namespace Prefix:	ewbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Rate at which the underlying collateral is expected to recover for future deferrals, used as an input to measure fair value.

+ References

No definition available.

+ Details

Name:	ewbc_FairValueInputsRecoveryRateForFutureDeferral
Namespace Prefix:	ewbc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 35

-Paragraph 34

-URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e25351-111560

+ Details

Name:	us-gaap_ImpairmentOfInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of addition (reduction) to the amount at which a liability could be incurred (settled) in a current transaction between willing parties.

+ References

No definition available.

+ Details

Name:	us-gaap_LiabilitiesFairValueAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

FAIR VALUE (Details 4) (USD $)	3 Months Ended		6 Months Ended
FAIR VALUE (Details 4) (USD $)	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Discount cash flow \| Derivative Payable
Quantitative unobservable assumptions
Total credit valuation adjustment on derivative liabilities			$ 933,000
Discount cash flow \| Derivative Payable \| Low end of range
Quantitative unobservable assumptions
Credit Risk Adjustment			0.68%
Discount cash flow \| Derivative Payable \| High end of range
Quantitative unobservable assumptions
Credit Risk Adjustment			0.71%
Trust Preferred Securities
Quantitative unobservable assumptions
Other than temporary impairment	$ 0	$ 0	$ 0	$ 0
Trust Preferred Securities \| Discount cash flow
Quantitative unobservable assumptions
Constant prepayment rate for year 1-5			0.00%
Constant prepayment rate, thereafter			1.00%
Constant default rate for year 1-5			1.20%
Constant default rate, thereafter			0.75%
Recovery rate, existing deferral/defaults			0.00%
Recovery rate, future deferral			15.00%
Recovery period, future deferral			60 months