XML 122 R120.htm IDEA: XBRL DOCUMENT
v2.4.1.9

STOCKHOLDERS' EQUITY AND EARNINGS PER SHARE (Details) (USD $) | 12 Months Ended | 0 Months Ended | 1 Months Ended | 3 Months Ended |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | ---
Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Jan. 17, 2014 | May 01, 2013 | Apr. 30, 2008 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2013 | Sep. 30, 2013 | Jun. 30, 2013 | Mar. 31, 2013 | Dec. 31, 2012 | Sep. 30, 2012 | Jun. 30, 2012 | Mar. 31, 2012 | Jan. 16, 2014 | Jul. 17, 2013 | Jan. 23, 2013 | Jan. 19, 2012
Class of Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock issued on conversion of convertible preferred stock |  | 5,594,080 us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Final consideration (in shares) | 5,583,093 us-gaap_StockIssuedDuringPeriodSharesAcquisitions |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Purchase of treasury stock pursuant to the Stock Repurchase Program, shares |  | 8,026,807 us-gaap_TreasuryStockSharesAcquired | 9,068,105 us-gaap_TreasuryStockSharesAcquired |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Weighted average price of shares repurchased (in dollars per share) |  | $ 24.89 us-gaap_TreasuryStockAcquiredAverageCostPerShare | $ 22.02 us-gaap_TreasuryStockAcquiredAverageCostPerShare |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Total cost of repurchase of treasury shares |  | $ 199,992,000 us-gaap_PaymentsForRepurchaseOfCommonStock | $ 199,950,000 us-gaap_PaymentsForRepurchaseOfCommonStock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Quarterly Dividends |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend per share (in dollars per share) | $ 0.72 us-gaap_CommonStockDividendsPerShareDeclared | $ 0.60 us-gaap_CommonStockDividendsPerShareDeclared | $ 0.40 us-gaap_CommonStockDividendsPerShareDeclared |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
MetroCorp |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Final consideration (in shares) |  |  |  | 5,583,093 us-gaap_StockIssuedDuringPeriodSharesAcquisitions / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Final consideration in cash |  |  |  | 89,400,000 us-gaap_PaymentsToAcquireBusinessesGross / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Fair value of warrants |  |  |  | 8,800,000 us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Cash paid to option holders |  |  |  | 2,400,000 ewbc_BusinessCombinationConsiderationTransferredAmountToAcquireeStockOptionHolders / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Warrants converted into the right to acquire shares |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 771,429 us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember |  |  |
Common stock equivalent to assumed obligation of holder's rights unexercised warrant (in shares) |  |  |  | 230,282 ewbc_CommonStockEquivalentToAssumedObligationOfHoldersRightsUnexercisedWarrant / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of warrants exercised | 0 ewbc_WarrantsExercised / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember |  |  |  |  |  | 0 ewbc_WarrantsExercised / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Series A Non-Cumulative Perpetual Convertible Preferred Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of shares issued during the period |  |  |  |  |  | 200,000 us-gaap_StockIssuedDuringPeriodSharesNewIssues / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred stock dividend rate (as a percent) |  |  |  |  |  | 8.00%us-gaap_PreferredStockDividendRatePercentage / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred stock liquidation preference (in dollars per share) |  |  |  |  |  | $ 1,000 us-gaap_PreferredStockLiquidationPreference / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from issuance of convertible preferred stock |  |  |  |  |  | 194,100,000 us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred shares converted |  |  |  |  | 85,710 us-gaap_StockRedeemedOrCalledDuringPeriodShares / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common stock issued on conversion of convertible preferred stock |  |  |  |  | 5,594,080 us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Quarterly Dividends |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend per share (in dollars per share) |  | $ 20.00 us-gaap_PreferredStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember | $ 20.00 us-gaap_PreferredStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred stock cash dividends paid |  | 3,400,000 us-gaap_DividendsPreferredStockCash / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember | 6,900,000 us-gaap_DividendsPreferredStockCash / us-gaap_StatementClassOfStockAxis = us-gaap_NonredeemableConvertiblePreferredStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Amount of stock repurchase approved by the Board of Directors |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 100,000,000 us-gaap_StockRepurchaseProgramAuthorizedAmount1 / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | 200,000,000 us-gaap_StockRepurchaseProgramAuthorizedAmount1 / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | 200,000,000 us-gaap_StockRepurchaseProgramAuthorizedAmount1 / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember
Quarterly Dividends |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividend per share (in dollars per share) |  |  |  |  |  |  | $ 0.18 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.18 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.18 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.18 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.15 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.15 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.15 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.15 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.10 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.10 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.10 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 0.10 us-gaap_CommonStockDividendsPerShareDeclared / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember |  |  |  |
Common stock cash dividends paid | $ 104,000,000 us-gaap_PaymentsOfDividendsCommonStock / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 83,300,000 us-gaap_PaymentsOfDividendsCommonStock / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember | $ 57,600,000 us-gaap_PaymentsOfDividendsCommonStock / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Common Stock | MetroCorp |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Final consideration (in shares) |  |  |  | 5,583,093 us-gaap_StockIssuedDuringPeriodSharesAcquisitions / us-gaap_BusinessAcquisitionAxis = ewbc_MetroCorpMember / us-gaap_StatementClassOfStockAxis = us-gaap_CommonStockMember |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |

X
- Definition Represents the amount given to acquiree's stock option holders by the acquirer as part of consideration transferred in a business combination. + References No definition available. + Details
Name: | ewbc_BusinessCombinationConsiderationTransferredAmountToAcquireeStockOptionHolders
Namespace Prefix: | ewbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the common stock equivalent to assumed obligation of holder's rights unexercised warrant. + References No definition available. + Details
Name: | ewbc_CommonStockEquivalentToAssumedObligationOfHoldersRightsUnexercisedWarrant
Namespace Prefix: | ewbc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the number of warrants exercised as of balance sheet date. + References No definition available. + Details
Name: | ewbc_WarrantsExercised
Namespace Prefix: | ewbc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of liabilities incurred by the acquirer as part of consideration transferred in a business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 25 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6911189&loc=d3e6405-128476 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477 + Details
Name: | us-gaap_BusinessCombinationConsiderationTransferredLiabilitiesIncurred
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph i -Subparagraph 2 -Article 4 + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Aggregate dividends declared during the period for each share of common stock outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
Name: | us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of paid and unpaid preferred stock dividends declared with the form of settlement in cash. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 405 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6957935&loc=d3e64057-112817 + Details
Name: | us-gaap_DividendsPreferredStockCash
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash outflow to reacquire common stock during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsForRepurchaseOfCommonStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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

X
- Definition Amount of cash outflow in the form of ordinary dividends to common shareholders of the parent entity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585 + Details
Name: | us-gaap_PaymentsOfDividendsCommonStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Investing Activities -URI http://asc.fasb.org/extlink&oid=6516133 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585 + Details
Name: | us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The percentage rate used to calculate dividend payments on preferred stock. + References No definition available. + Details
Name: | us-gaap_PreferredStockDividendRatePercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Aggregate dividends declared during the period for each share of preferred stock outstanding. + References No definition available. + Details
Name: | us-gaap_PreferredStockDividendsPerShareDeclared
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The per share liquidation preference (or restrictions) of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) that has a preference in involuntary liquidation considerably in excess of the par or stated value of the shares. The liquidation preference is the difference between the preference in liquidation and the par or stated values of the share. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21484-112644 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 08 -Paragraph d -Article 4 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(d)(1)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
Name: | us-gaap_PreferredStockLiquidationPreference
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash inflow from issuance of preferred stocks identified as being convertible into another form of financial instrument, typically the entity's common stock. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Financing Activities -URI http://asc.fasb.org/extlink&oid=6513228 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585 + Details
Name: | us-gaap_ProceedsFromIssuanceOfConvertiblePreferredStock
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of shares of stock issued during the period pursuant to acquisitions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.28,29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesAcquisitions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares issued during the period as a result of the conversion of convertible securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21475-112644 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 Reference 6: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29-30) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesConversionOfConvertibleSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of new stock issued during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesNewIssues
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of stock bought back by the entity at the exercise price or redemption price. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 + Details
Name: | us-gaap_StockRedeemedOrCalledDuringPeriodShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of stock repurchase plan authorized. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 + Details
Name: | us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares that have been repurchased during the period and are being held in treasury. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Article 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 29, 30 -Article 5 + Details
Name: | us-gaap_TreasuryStockSharesAcquired
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=ewbc_MetroCorpMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_NonredeemableConvertiblePreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |