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REGULATORY REQUIREMENTS AND MATTERS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Actual
Total Capital (to Risk-Weighted Assets), Amount	$ 3,082,945,000	$ 2,753,599,000
Tier I Capital (to Risk-Weighted Assets), Amount	2,686,627,000	2,405,452,000
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Amount	2,650,413,000
Tier I Capital (to Average Assets), Amount	2,686,627,000	2,405,452,000
Risk weighted assets	$ 25,232,575,000	21,931,486,000
Adjusted quarterly average total assets		$ 28,501,115
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	12.20%	12.60%
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	10.70%	11.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	10.50%
Tier I Capital (to Average Assets), Ratio (as a percent)	8.50%	8.40%
Minimum Requirement
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)	6.00%	4.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	4.50%
Tier I Capital (to Average Assets), Ratio (as a percent)	4.00%	4.00%
Well Capitalized Requirement
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)	8.00%	6.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	6.50%
Tier I Capital (to Average Assets), Ratio (as a percent)	5.00%	5.00%
East West Bank
Actual
Total Capital (to Risk-Weighted Assets), Amount	$ 3,039,524,000	$ 2,590,173,000
Tier I Capital (to Risk-Weighted Assets), Amount	2,754,201,000	2,316,615,000
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Amount	2,754,201,000
Tier I Capital (to Average Assets), Amount	$ 2,754,201,000	2,316,615,000
Risk weighted assets		21,875,078
Adjusted quarterly average total assets		$ 28,418,340
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	12.10%	11.80%
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	11.00%	10.60%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	11.00%
Tier I Capital (to Average Assets), Ratio (as a percent)	8.80%	8.20%
Minimum Requirement
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)	6.00%	4.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	4.50%
Tier I Capital (to Average Assets), Ratio (as a percent)	4.00%	4.00%
Well Capitalized Requirement
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)	8.00%	6.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	6.50%
Tier I Capital (to Average Assets), Ratio (as a percent)	5.00%	5.00%
Reserve Requirement
Daily average reserve requirement	$ 395,600,000	$ 325,700,000

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