XML 111 R90.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Loans Receivable and Allowance for Credit Losses (Summary of Activities in Allowance for Loan Losses) (Details) - USD ($) $ in Thousands |  | 12 Months Ended
--- | --- | ---
Jan. 01, 2019 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses |  |  |  |  |
Accounting Standards Update [Extensible List] | Accounting Standards Update 2016-02 |  | Accounting Standards Update 2016-13 |  | Accounting Standards Update 2016-13
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period | $ 311,322 | $ 619,983 | $ 358,287 | $ 311,322 |
(Reversal of ) provision for credit losses on loans |  | (28,937) | 198,691 | 100,093 |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Gross charge-offs |  | (66,592) | (81,837) | (75,067) |
Gross recoveries |  | 16,614 | 18,672 | 22,264 |
Total net (charge-offs) recoveries |  | (49,978) | (63,165) | (52,803) |
Foreign currency translation adjustment |  | 511 | 1,012 | (325) |
Allowance for loan losses, balance at the end of the period |  | 541,579 | 619,983 | 358,287 | $ 311,322
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period |  |  | 125,158 |  |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Allowance for loan losses, balance at the end of the period |  |  |  | 125,158 |
Commercial Lending | C&I |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period | 189,117 | 398,040 | 238,376 | 189,117 |
(Reversal of ) provision for credit losses on loans |  | (39,715) | 145,212 | 109,068 |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Gross charge-offs |  | (32,490) | (66,225) | (73,985) |
Gross recoveries |  | 11,906 | 5,428 | 14,501 |
Total net (charge-offs) recoveries |  | (20,584) | (60,797) | (59,484) |
Foreign currency translation adjustment |  | 511 | 1,012 | (325) |
Allowance for loan losses, balance at the end of the period |  | 338,252 | 398,040 | 238,376 | 189,117
Commercial Lending | C&I | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period |  |  | 74,237 |  |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Allowance for loan losses, balance at the end of the period |  |  |  | 74,237 |
Commercial Lending | CRE |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period | 40,666 | 163,791 | 40,509 | 40,666 |
(Reversal of ) provision for credit losses on loans |  | 14,282 | 55,864 | (4,345) |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Gross charge-offs |  | (28,430) | (15,206) | (1,021) |
Gross recoveries |  | 1,297 | 10,455 | 5,209 |
Total net (charge-offs) recoveries |  | (27,133) | (4,751) | 4,188 |
Foreign currency translation adjustment |  | 0 | 0 | 0 |
Allowance for loan losses, balance at the end of the period |  | 150,940 | 163,791 | 40,509 | 40,666
Commercial Lending | CRE | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period |  |  | 72,169 |  |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Allowance for loan losses, balance at the end of the period |  |  |  | 72,169 |
Commercial Lending | Residential loan | Multifamily |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period | 19,885 | 27,573 | 22,826 | 19,885 |
(Reversal of ) provision for credit losses on loans |  | (15,076) | 10,879 | 1,085 |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Gross charge-offs |  | (130) | 0 | 0 |
Gross recoveries |  | 2,033 | 1,980 | 1,856 |
Total net (charge-offs) recoveries |  | 1,903 | 1,980 | 1,856 |
Foreign currency translation adjustment |  | 0 | 0 | 0 |
Allowance for loan losses, balance at the end of the period |  | 14,400 | 27,573 | 22,826 | 19,885
Commercial Lending | Residential loan | Multifamily | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period |  |  | (8,112) |  |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Allowance for loan losses, balance at the end of the period |  |  |  | (8,112) |
Commercial Lending | Construction and land |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period | 20,290 | 10,239 | 19,404 | 20,290 |
(Reversal of ) provision for credit losses on loans |  | 7,576 | 644 | (1,422) |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Gross charge-offs |  | (2,954) | 0 | 0 |
Gross recoveries |  | 607 | 80 | 536 |
Total net (charge-offs) recoveries |  | (2,347) | 80 | 536 |
Foreign currency translation adjustment |  | 0 | 0 | 0 |
Allowance for loan losses, balance at the end of the period |  | 15,468 | 10,239 | 19,404 | 20,290
Commercial Lending | Construction and land | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period |  |  | (9,889) |  |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Allowance for loan losses, balance at the end of the period |  |  |  | (9,889) |
Consumer Lending | Residential loan | Single-family |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period | 31,340 | 15,520 | 28,527 | 31,340 |
(Reversal of ) provision for credit losses on loans |  | 1,965 | (9,922) | (2,938) |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Gross charge-offs |  | (1,046) | 0 | (11) |
Gross recoveries |  | 721 | 585 | 136 |
Total net (charge-offs) recoveries |  | (325) | 585 | 125 |
Foreign currency translation adjustment |  | 0 | 0 | 0 |
Allowance for loan losses, balance at the end of the period |  | 17,160 | 15,520 | 28,527 | 31,340
Consumer Lending | Residential loan | Single-family | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period |  |  | (3,670) |  |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Allowance for loan losses, balance at the end of the period |  |  |  | (3,670) |
Consumer Lending | HELOCs |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period | 5,774 | 2,690 | 5,265 | 5,774 |
(Reversal of ) provision for credit losses on loans |  | 745 | (605) | (516) |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Gross charge-offs |  | (45) | (221) | 0 |
Gross recoveries |  | 45 | 49 | 7 |
Total net (charge-offs) recoveries |  | 0 | (172) | 7 |
Foreign currency translation adjustment |  | 0 | 0 | 0 |
Allowance for loan losses, balance at the end of the period |  | 3,435 | 2,690 | 5,265 | 5,774
Consumer Lending | HELOCs | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period |  |  | (1,798) |  |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Allowance for loan losses, balance at the end of the period |  |  |  | (1,798) |
Consumer Lending | Other consumer |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period | $ 4,250 | 2,130 | 3,380 | 4,250 |
(Reversal of ) provision for credit losses on loans |  | 1,286 | (3,381) | (839) |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Gross charge-offs |  | (1,497) | (185) | (50) |
Gross recoveries |  | 5 | 95 | 19 |
Total net (charge-offs) recoveries |  | (1,492) | (90) | (31) |
Foreign currency translation adjustment |  | 0 | 0 | 0 |
Allowance for loan losses, balance at the end of the period |  | $ 1,924 | 2,130 | 3,380 | $ 4,250
Consumer Lending | Other consumer | Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2016-13 |  |  |  |  |
Allowance for loan losses |  |  |  |  |
Allowance for loan losses, balance at the beginning of the period |  |  | $ 2,221 |  |
Net Charge-Off/Recoveries [Abstract] |  |  |  |  |
Allowance for loan losses, balance at the end of the period |  |  |  | $ 2,221 |

X
- Definition Financing Receivable, Allowance for Credit Loss, Write Off, Net Of Recovery + References No definition available. + Details
Name: | ewbc_FinancingReceivableAllowanceForCreditLossWriteOffNetOfRecovery
Namespace Prefix: | ewbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net Charge-Off/Recoveries + References No definition available. + Details
Name: | ewbc_NetChargeOffRecoveriesAbstract
Namespace Prefix: | ewbc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition (Reversal of) Provision for Credit Losses on Loans and Provision for Loan Losses + References No definition available. + Details
Name: | ewbc_ReversalOfProvisionForCreditLossesOnLoansAndProvisionForLoanLosses
Namespace Prefix: | ewbc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Indicates amendment to accounting standards. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123597120&loc=SL121967933-165497 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123597120&loc=SL121967933-165497 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (e)(2) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 7: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 8: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 9: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (h)(2) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 10: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 11: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 12: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 7 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123597120&loc=SL122642865-165497 Reference 13: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22499-107794 Reference 14: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 65 -Paragraph 8 -Subparagraph (d)(3) -URI http://asc.fasb.org/extlink&oid=123459177&loc=SL121830611-158277 Reference 15: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=123597120&loc=SL121967933-165497 Reference 16: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(4) -URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22499-107794 Reference 17: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=123597120&loc=SL121967933-165497 Reference 18: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22499-107794 Reference 19: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 5 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=123597120&loc=SL120254526-165497 Reference 20: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (b)(1) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 21: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (g)(2)(iv) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 22: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 105 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695 Reference 23: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (g)(2)(iii) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 24: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 105 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695 Reference 25: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 26: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (h)(1) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 27: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 250 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=124431687&loc=d3e22499-107794 Reference 28: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437 Reference 29: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 30: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 65 -Paragraph 8 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=123459177&loc=SL121830611-158277 Reference 31: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437 Reference 32: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 33: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (g)(2)(ii) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 34: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 105 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695 Reference 35: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 36: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 848 -SubTopic 10 -Section 65 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=122150657&loc=SL122150809-237846 Reference 37: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (g)(1) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 38: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 7 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123597120&loc=SL122642865-165497 Reference 39: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 10 -Section S65 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124359872&loc=SL124427846-239511 Reference 40: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 20 -Section 65 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=124402435&loc=SL124402458-218513 Reference 41: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 20 -Section 65 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=124402435&loc=SL124402458-218513 Reference 42: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 65 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123597120&loc=SL120254526-165497 Reference 43: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 44: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437 Reference 45: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (g)(2)(i) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 46: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 105 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695 Reference 47: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437 Reference 48: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 49: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 105 -SubTopic 10 -Section 65 -Paragraph 6 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=124434974&loc=SL124442142-165695 Reference 50: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (e)(3) -URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437 Reference 51: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 52: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 53: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 54: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 55: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 10 -Section 65 -Paragraph 4 -Subparagraph (e)(4) -URI http://asc.fasb.org/extlink&oid=122640432&loc=SL121648383-210437 Reference 56: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 65 -Paragraph 15 -Subparagraph (g)(2) -URI http://asc.fasb.org/extlink&oid=121322162&loc=SL121327923-165333 Reference 57: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (e)(3) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 58: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 65 -Paragraph 2 -Subparagraph (f)(1) -URI http://asc.fasb.org/extlink&oid=124501264&loc=SL117420844-207641 Reference 59: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (e)(4) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 60: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 40 -Section 65 -Paragraph 1 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=123482062&loc=SL123482106-238011 Reference 61: http://www.xbrl.org/2003/role/disclosureRef -Topic 848 -SubTopic 10 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Publisher FASB -Subparagraph (a) Reference 62: http://www.xbrl.org/2003/role/disclosureRef -Topic 848 -SubTopic 10 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Publisher FASB -Subparagraph (a)(1) Reference 63: http://www.xbrl.org/2003/role/disclosureRef -Topic 848 -SubTopic 10 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Publisher FASB -Subparagraph (a)(2) Reference 64: http://www.xbrl.org/2003/role/disclosureRef -Topic 848 -SubTopic 10 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Publisher FASB -Subparagraph (a)(3)(iii)(01) Reference 65: http://www.xbrl.org/2003/role/disclosureRef -Topic 848 -SubTopic 10 -Name Accounting Standards Codification -Section 65 -Paragraph 2 -Publisher FASB -Subparagraph (a)(3)(iii)(03) + Details
Name: | us-gaap_AccountingStandardsUpdateExtensibleList
Namespace Prefix: | us-gaap_
Data Type: | enum2:enumerationSetItemType
Balance Type: | na
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_AllowanceForLoanAndLeaseLossesRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount excluding accrued interest, of allowance for credit loss on financing receivable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=124255206&loc=SL82895884-210446 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of foreign currency translation gain (loss) which (increases) decreases allowance for credit loss on financing receivable. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossForeignCurrencyTranslation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of increase in allowance for credit loss on financing receivable from recovery. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(4) -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Amount of writeoff of financing receivable, charged against allowance for credit loss. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 50 -Paragraph 13 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 11B -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=123577603&loc=SL6953423-111524 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 326 -SubTopic 20 -Section 55 -Paragraph 79 -URI http://asc.fasb.org/extlink&oid=124267575&loc=SL82922352-210448 + Details
Name: | us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_CumulativeEffectPeriodOfAdoptionAxis=srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201613Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_CommercialPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ewbc_CommercialAndIndustrialLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialRealEstateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_RealEstateLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=srt_MultifamilyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ewbc_ConstructionAndLandLoanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivablePortfolioSegmentAxis=us-gaap_ConsumerPortfolioSegmentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=srt_SingleFamilyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_HomeEquityMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=ewbc_OtherConsumerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |