REGULATORY REQUIREMENTS AND MATTERS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Actual
Total Capital (to Risk-Weighted Assets), Amount	$ 3,400,642	$ 3,082,945
Tier I Capital (to Risk-Weighted Assets), Amount	2,976,002	2,686,627
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Amount	2,976,002	2,650,413
Tier I Capital (to Average Assets), Amount	2,976,002	2,686,627
Risk weighted assets	27,357,753	25,232,575
Adjusted quarterly average total assets	$ 34,209,827	$ 31,458,517
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	12.40%	12.20%
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	10.90%	10.70%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	10.90%	10.50%
Tier I Capital (to Average Assets), Ratio (as a percent)	8.70%	8.50%
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%	6.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	4.50%	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%	8.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	6.50%	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	$ 3,371,885	$ 3,039,524
Tier I Capital (to Risk-Weighted Assets), Amount	3,095,245	2,754,201
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Amount	3,095,245	2,754,201
Tier I Capital (to Average Assets), Amount	3,095,245	2,754,201
Risk weighted assets	27,310,540	25,129,885
Adjusted quarterly average total assets	$ 34,163,667	$ 31,385,333
Total Capital (to Risk-Weighted Assets), Ratio (as a percent)	12.30%	12.10%
Tier I Capital (to Risk-Weighted Assets), Ratio (as a percent)	11.30%	11.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	11.30%	11.00%
Tier I Capital (to Average Assets), Ratio (as a percent)	9.10%	8.80%
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%	6.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	4.50%	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%	8.00%
Tier 1 Common Equity Capital (to Risk-Weighted Assets), Ratio (as a percent)	6.50%	6.50%
Tier I Capital (to Average Assets), Ratio (as a percent)	5.00%	5.00%
Reserve Requirement
Daily average reserve requirement	$ 503,800	$ 395,600