REGULATORY REQUIREMENTS (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Actual
Total Capital (to Risk-Weighted Assets), Amount	$ 2,753,598,000us-gaap_Capital	$ 2,395,109,000us-gaap_Capital
Tier I Capital (to Risk-Weighted Assets), Amount	2,405,452,000us-gaap_TierOneRiskBasedCapital	2,102,476,000us-gaap_TierOneRiskBasedCapital
Tier I Capital (to Average Assets), Amount	2,405,452,000us-gaap_TierOneLeverageCapital	2,102,476,000us-gaap_TierOneLeverageCapital
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	12.60%us-gaap_CapitalToRiskWeightedAssets	13.50%us-gaap_CapitalToRiskWeightedAssets
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	11.00%	11.90%
Tier I Capital (to Average Assets), Ratio (as a percent)	8.40%	8.60%
For Capital Adequacy Purposes
Total Capital (to Risk-Weighted Assets), Amount	1,754,519,000	1,416,203,000
Tier I Capital (to Risk-Weighted Assets), Amount	877,259,000	708,102,000
Tier I Capital (to Average Assets), Amount	1,140,045,000	976,596,000
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	8.00%	8.00%
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	4.00%	4.00%
Tier I Capital (to Average Assets), Ratio (as a percent)	4.00%	4.00%
Regulatory Requirements - Additional Disclosure
Minimum total consolidated assets for exclusion of trust preferred securities as Tier I regulatory capital	15,000,000,000
Trust preferred securities as a percentage of the Company's Tier I capital	3.10%	4.40%
Minimum value of assets held by depository institutions and top-tier bank holding companies to be in compliance with the Basel III Capital Rules	500,000,000
East West Bank
Actual
Total Capital (to Risk-Weighted Assets), Amount	2,590,174,000	2,262,494,000
Tier I Capital (to Risk-Weighted Assets), Amount	2,316,615,000	2,041,894,000
Tier I Capital (to Average Assets), Amount	2,316,615,000	2,041,894,000
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	11.80%	12.90%
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	10.60%	11.60%
Tier I Capital (to Average Assets), Ratio (as a percent)	8.20%	8.40%
For Capital Adequacy Purposes
Total Capital (to Risk-Weighted Assets), Amount	1,750,006,000	1,407,944,000
Tier I Capital (to Risk-Weighted Assets), Amount	875,003,000	703,972,000
Tier I Capital (to Average Assets), Amount	1,136,734,000	973,958,000
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	8.00%	8.00%
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	4.00%	4.00%
Tier I Capital (to Average Assets), Ratio (as a percent)	4.00%	4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions
Total Capital (to Risk-Weighted Assets), Amount	2,187,508,000	1,759,931,000
Tier I Capital (to Risk-Weighted Assets), Amount	1,312,505,000	1,055,958,000
Tier I Capital (to Average Assets), Amount	1,420,917,000	1,217,448,000
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	10.00%	10.00%
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	6.00%	6.00%
Tier I Capital (to Average Assets), Ratio (as a percent)	5.00%	5.00%
Reserve Requirement
Daily average reserve requirement	$ 325,700,000	$ 218,500,000

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The minimum value of assets held by depository institutions and top-tier bank holding companies to be in compliance with the Basel III Capital Rules.

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The amount of total capital as defined in the regulations.

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The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations.

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Tier 1 Leverage Capital divided by average assets as defined in the regulations.

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Tier 1 Risk Based Capital as defined in the regulations.

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The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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