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Loans Receivable and Allowance for Credit Losses (Summary of Activities in Allowance for Loan Losses by Portfolio Segments and Unfunded Credit Commitments) (Details) - USD ($) | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2020 | Jun. 30, 2019 | Jun. 30, 2020 | Jun. 30, 2019 | Dec. 31, 2019 | Dec. 31, 2018
Financing Receivable Allowance for Credit Losses |  |  |  |  |  |  |  |
Accounting Standards Update [Extensible List] |  |  | us-gaap:AccountingStandardsUpdate201613Member |  | us-gaap:AccountingStandardsUpdate201613Member | [1] | us-gaap:AccountingStandardsUpdate201602Member | [2]
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | $ 358,287,000 |  |  |  |  |
Provision for credit losses | $ 102,443,000 | $ 19,245,000 | 176,313,000 | $ 41,824,000 |  |  |  |
Gross charge-offs | 0 | (317,000) | 0 | (390,000) |  |  |  |
Allowance, end of period | 632,071,000 |  | 632,071,000 |  | $ 358,287,000 |  |  |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | 102,443,000 | 19,245,000 | 176,313,000 | 41,824,000 |  |  |  |
PCD or PCI loans |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 0 |  |  |  |  |
Allowance, end of period |  |  |  |  | 0 |  |  |
Commercial and industrial (“C&I”) |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, end of period | 756,000 |  | 756,000 |  |  |  |  |
HELOCs |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, end of period | 76,000 |  | 76,000 |  |  |  |  |
Unfunded Credit Commitments |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Provision for credit losses | 8,143,000 | (1,486,000) | 7,357,000 | 453,000 |  |  |  |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Allowance for Unfunded Credit Commitments | 20,829,000 | 14,505,000 | 11,158,000 | 12,566,000 | 12,566,000 |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | 8,143,000 | (1,486,000) | 7,357,000 | 453,000 |  |  |  |
Allowance for Unfunded Credit Commitments | 28,972,000 | 13,019,000 | 28,972,000 | 13,019,000 | 11,158,000 |  | $ 12,566,000 |
Unfunded Credit Commitments | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Allowance for Unfunded Credit Commitments | 0 | 0 | 10,457,000 | 0 | 0 |  |  |
Allowance for Unfunded Credit Commitments |  |  |  |  | 10,457,000 |  | 0 |
Commercial lending | Commercial and industrial (“C&I”) |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period | 362,629,000 | 189,757,000 | 238,376,000 | 189,117,000 | 189,117,000 |  |  |
Provision for credit losses | 37,862,000 | 26,140,000 | 98,480,000 | 41,404,000 |  |  |  |
Gross charge-offs | (20,378,000) | (11,745,000) | (32,355,000) | (28,989,000) |  |  |  |
Gross recoveries | 602,000 | 1,713,000 | 2,177,000 | 3,964,000 |  |  |  |
Total net (charge-offs) recoveries | (19,776,000) | (10,032,000) | (30,178,000) | (25,025,000) |  |  |  |
Foreign currency translation adjustments | 8,000 | (362,000) | (192,000) | 7,000 |  |  |  |
Allowance, end of period | 380,723,000 | 205,503,000 | 380,723,000 | 205,503,000 | 238,376,000 |  | 189,117,000 |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | 37,862,000 | 26,140,000 | 98,480,000 | 41,404,000 |  |  |  |
Commercial lending | Commercial and industrial (“C&I”) | PCD or PCI loans |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 0 |  |  |  |  |
Allowance, end of period |  |  |  |  | 0 |  |  |
Commercial lending | Commercial and industrial (“C&I”) | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 74,237,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 74,237,000 |  |  |
Commercial lending | Commercial and industrial (“C&I”) | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 312,613,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 312,613,000 |  |  |
Commercial lending | Commercial real estate (“CRE”) |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period | 132,819,000 | 39,224,000 | 40,509,000 | 40,666,000 | 40,666,000 |  |  |
Provision for credit losses | 43,315,000 | (1,250,000) | 54,750,000 | (2,914,000) |  |  |  |
Gross charge-offs | (320,000) | 0 | (1,274,000) | 0 |  |  |  |
Gross recoveries | 226,000 | 1,837,000 | 9,886,000 | 2,059,000 |  |  |  |
Total net (charge-offs) recoveries | (94,000) | 1,837,000 | 8,612,000 | 2,059,000 |  |  |  |
Foreign currency translation adjustments | 0 |  | 0 | 0 |  |  |  |
Allowance, end of period | 176,040,000 | 39,811,000 | 176,040,000 | 39,811,000 | 40,509,000 |  | 40,666,000 |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | 43,315,000 | (1,250,000) | 54,750,000 | (2,914,000) |  |  |  |
Commercial lending | Commercial real estate (“CRE”) | PCD or PCI loans |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 0 |  |  |  |  |
Allowance, end of period |  |  |  |  | 0 |  |  |
Commercial lending | Commercial real estate (“CRE”) | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 72,169,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 72,169,000 |  |  |
Commercial lending | Commercial real estate (“CRE”) | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 112,678,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 112,678,000 |  |  |
Commercial lending | Real estate loan | Multifamily residential |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period | 16,530,000 | 19,169,000 | 22,826,000 | 19,885,000 | 19,885,000 |  |  |
Provision for credit losses | 7,908,000 | 58,000 | 9,189,000 | (939,000) |  |  |  |
Gross charge-offs | 0 | 0 | 0 | 0 |  |  |  |
Gross recoveries | 620,000 | 53,000 | 1,155,000 | 334,000 |  |  |  |
Total net (charge-offs) recoveries | 620,000 | 53,000 | 1,155,000 | 334,000 |  |  |  |
Foreign currency translation adjustments | 0 |  | 0 | 0 |  |  |  |
Allowance, end of period | 25,058,000 | 19,280,000 | 25,058,000 | 19,280,000 | 22,826,000 |  | 19,885,000 |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | 7,908,000 | 58,000 | 9,189,000 | (939,000) |  |  |  |
Commercial lending | Real estate loan | Multifamily residential | PCD or PCI loans |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 0 |  |  |  |  |
Allowance, end of period |  |  |  |  | 0 |  |  |
Commercial lending | Real estate loan | Multifamily residential | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | (8,112,000) |  |  |  |  |
Allowance, end of period |  |  |  |  | (8,112,000) |  |  |
Commercial lending | Real estate loan | Multifamily residential | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 14,714,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 14,714,000 |  |  |
Commercial lending | Construction and land |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period | 11,018,000 | 22,349,000 | 19,404,000 | 20,290,000 | 20,290,000 |  |  |
Provision for credit losses | 7,526,000 | 173,000 | 9,008,000 | 2,169,000 |  |  |  |
Gross charge-offs | 0 | 0 | 0 | 0 |  |  |  |
Gross recoveries | 7,000 | 439,000 | 28,000 | 502,000 |  |  |  |
Total net (charge-offs) recoveries | 7,000 | 439,000 | 28,000 | 502,000 |  |  |  |
Foreign currency translation adjustments | 0 |  | 0 | 0 |  |  |  |
Allowance, end of period | 18,551,000 | 22,961,000 | 18,551,000 | 22,961,000 | 19,404,000 |  | 20,290,000 |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | 7,526,000 | 173,000 | 9,008,000 | 2,169,000 |  |  |  |
Commercial lending | Construction and land | PCD or PCI loans |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 0 |  |  |  |  |
Allowance, end of period |  |  |  |  | 0 |  |  |
Commercial lending | Construction and land | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | (9,889,000) |  |  |  |  |
Allowance, end of period |  |  |  |  | (9,889,000) |  |  |
Commercial lending | Construction and land | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 9,515,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 9,515,000 |  |  |
Consumer lending | Real estate loan | Single-family residential |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period | 26,822,000 | 35,759,000 | 28,527,000 | 31,340,000 | 31,340,000 |  |  |
Provision for credit losses | (1,667,000) | (3,068,000) | 33,000 | 1,349,000 |  |  |  |
Gross charge-offs | 0 | 0 | 0 | 0 |  |  |  |
Gross recoveries | 159,000 | 72,000 | 424,000 | 74,000 |  |  |  |
Total net (charge-offs) recoveries | 159,000 | 72,000 | 424,000 | 74,000 |  |  |  |
Foreign currency translation adjustments | 0 |  | 0 | 0 |  |  |  |
Allowance, end of period | 25,314,000 | 32,763,000 | 25,314,000 | 32,763,000 | 28,527,000 |  | 31,340,000 |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | (1,667,000) | (3,068,000) | 33,000 | 1,349,000 |  |  |  |
Consumer lending | Real estate loan | Single-family residential | PCD or PCI loans |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 0 |  |  |  |  |
Allowance, end of period |  |  |  |  | 0 |  |  |
Consumer lending | Real estate loan | Single-family residential | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | (3,670,000) |  |  |  |  |
Allowance, end of period |  |  |  |  | (3,670,000) |  |  |
Consumer lending | Real estate loan | Single-family residential | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 24,857,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 24,857,000 |  |  |
Consumer lending | HELOCs |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period | 3,881,000 | 7,401,000 | 5,265,000 | 5,774,000 | 5,774,000 |  |  |
Provision for credit losses | 205,000 | (1,224,000) | 617,000 | 401,000 |  |  |  |
Gross charge-offs | (221,000) | 0 | (221,000) | 0 |  |  |  |
Gross recoveries | 2,000 | 0 | 4,000 | 2,000 |  |  |  |
Total net (charge-offs) recoveries | (219,000) | 0 | (217,000) | 2,000 |  |  |  |
Foreign currency translation adjustments | 0 |  | 0 | 0 |  |  |  |
Allowance, end of period | 3,867,000 | 6,177,000 | 3,867,000 | 6,177,000 | 5,265,000 |  | 5,774,000 |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | 205,000 | (1,224,000) | 617,000 | 401,000 |  |  |  |
Consumer lending | HELOCs | PCD or PCI loans |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 0 |  |  |  |  |
Allowance, end of period |  |  |  |  | 0 |  |  |
Consumer lending | HELOCs | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | (1,798,000) |  |  |  |  |
Allowance, end of period |  |  |  |  | (1,798,000) |  |  |
Consumer lending | HELOCs | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 3,467,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 3,467,000 |  |  |
Consumer lending | Other consumer |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period | 3,304,000 | 4,235,000 | 3,380,000 | 4,250,000 | 4,250,000 |  |  |
Provision for credit losses | (849,000) | (98,000) | (3,121,000) | (99,000) |  |  |  |
Gross charge-offs | (30,000) | (14,000) | (56,000) | (28,000) |  |  |  |
Gross recoveries | 93,000 | 7,000 | 94,000 | 7,000 |  |  |  |
Total net (charge-offs) recoveries | 63,000 | (7,000) | 38,000 | (21,000) |  |  |  |
Foreign currency translation adjustments | 0 |  | 0 | 0 |  |  |  |
Allowance, end of period | 2,518,000 | 4,130,000 | 2,518,000 | 4,130,000 | 3,380,000 |  | 4,250,000 |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | (849,000) | (98,000) | (3,121,000) | (99,000) |  |  |  |
Consumer lending | Other consumer | PCD or PCI loans |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 0 |  |  |  |  |
Allowance, end of period |  |  |  |  | 0 |  |  |
Consumer lending | Other consumer | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 2,221,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 2,221,000 |  |  |
Consumer lending | Other consumer | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 5,601,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 5,601,000 |  |  |
Commercial and consumer lending |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period | 557,003,000 | 317,894,000 | 358,287,000 | 311,322,000 | 311,322,000 |  |  |
Provision for credit losses | 94,300,000 | 20,731,000 | 168,956,000 | 41,371,000 |  |  |  |
Gross charge-offs | (20,949,000) | (11,759,000) | (33,906,000) | (29,017,000) |  |  |  |
Gross recoveries | 1,709,000 | 4,121,000 | 13,768,000 | 6,942,000 |  |  |  |
Total net (charge-offs) recoveries | (19,240,000) | (7,638,000) | (20,138,000) | (22,075,000) |  |  |  |
Foreign currency translation adjustments | 8,000 | (362,000) | (192,000) | 7,000 |  |  |  |
Allowance, end of period | 632,071,000 | 330,625,000 | 632,071,000 | 330,625,000 | 358,287,000 |  | $ 311,322,000 |
Allowance for unfunded credit commitments |  |  |  |  |  |  |  |
Provision for (reversal of) credit losses on unfunded credit commitments | $ 94,300,000 | $ 20,731,000 | 168,956,000 | $ 41,371,000 |  |  |  |
Commercial and consumer lending | Cumulative Effect, Period Of Adoption, Adjustment |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | 125,158,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | 125,158,000 |  |  |
Commercial and consumer lending | Cumulative Effect, Period of Adoption, Adjusted Balance |  |  |  |  |  |  |  |
Allowance for loan losses by portfolio segments |  |  |  |  |  |  |  |
Allowance, beginning of period |  |  | $ 483,445,000 |  |  |  |  |
Allowance, end of period |  |  |  |  | $ 483,445,000 |  |  |
[1] | Represents the impact of the adoption of ASU 2016-13, Financial Instruments - Credit Losses (Topic 326) in the first quarter of 2020. Refer to Note 2 — Current Accounting Developments and Summary of Significant Accounting Policies to the Consolidated Financial Statements in this Quarterly Report on Form 10-Q (“this Form 10-Q”) for additional information.
[2] | Represents the impact of the adoption of Accounting Standards Update (“ASU”) 2016-02, Leases (Topic 842) and subsequent related ASUs in the first quarter of 2019.

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- Definition Allowance For Unfunded Credit Reserves [Roll Forward] + References No definition available. + Details
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- Definition Reflects the Allowance for Unfunded Credit Commitments + References No definition available. + Details
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Namespace Prefix: | ewbc_
Data Type: | xbrli:monetaryItemType
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