Regulatory Requirements and Matters - Regulatory Capital Information (Details) $ in Thousands	Dec. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Minimum Regulatory Requirements
Total capital ratio required for capital adequacy to risk weighted assets	0.080
Tier 1 capital ratio required for capital adequacy to risk weighted assets	0.060
Common equity tier 1 capital adequacy to risk weighted assets	0.045
Tier 1 leverage capital (to adjusted quarterly average assets), Ratio (as a percent)	0.040
Well-Capitalized Requirement
Fully phased-in capital conservation buffer	2.50%
Company
Actual
Total capital (to risk-weighted assets), Amount	$ 8,561,797	$ 7,919,407
Tier I capital (to risk-weighted assets), Amount	7,839,816	7,140,778
CET1 capital (to risk-weighted assets), Amount	7,839,816	7,140,778
Tier 1 leverage capital (to adjusted quarterly average assets), Amount	$ 7,839,816	$ 7,140,778
Total capital (to risk-weighted assets), Ratio (as a percent)	0.156	0.148
Tier I capital (to risk-weighted assets), Ratio (as a percent)	0.143	0.133
CET1 capital (to risk-weighted assets), Ratio (as a percent)	0.143	0.133
Tier 1 leverage capital (to adjusted quarterly average assets), Ratio (as a percent)	0.104	0.102
Minimum Regulatory Requirements
Total capital ratio required for capital adequacy to risk weighted assets	0.080
Tier 1 capital ratio required for capital adequacy to risk weighted assets	0.060
Common equity tier 1 capital adequacy to risk weighted assets	0.045
Tier 1 leverage capital (to adjusted quarterly average assets), Ratio (as a percent)	0.040
Minimum Regulatory Requirements including Capital Conservation Buffer
Total capital (to risk-weighted assets), Ratio (as a percent)	10.50%
Tier I capital (to risk-weighted assets), Ratio (as a percent)	8.50%
CET1 capital (to risk-weighted assets), Ratio (as a percent)	7.00%
Tier 1 leverage capital (to adjusted quarterly average assets), Ratio (as a percent)	4.00%
Well-Capitalized Requirement
Total capital (to risk-weighted assets), Ratio (as a percent)	0.100
Tier I capital (to risk-weighted assets), Ratio (as a percent)	0.060
East West Bank
Actual
Total capital (to risk-weighted assets), Amount	$ 8,053,389	$ 7,363,575
Tier I capital (to risk-weighted assets), Amount	7,367,996	6,732,946
CET1 capital (to risk-weighted assets), Amount	7,367,996	6,732,946
Tier 1 leverage capital (to adjusted quarterly average assets), Amount	$ 7,367,996	$ 6,732,946
Total capital (to risk-weighted assets), Ratio (as a percent)	0.147	0.138
Tier I capital (to risk-weighted assets), Ratio (as a percent)	0.134	0.126
CET1 capital (to risk-weighted assets), Ratio (as a percent)	0.134	0.126
Tier 1 leverage capital (to adjusted quarterly average assets), Ratio (as a percent)	0.098	0.096
Minimum Regulatory Requirements
Total capital ratio required for capital adequacy to risk weighted assets	0.080
Tier 1 capital ratio required for capital adequacy to risk weighted assets	0.060
Common equity tier 1 capital adequacy to risk weighted assets	0.045
Tier 1 leverage capital (to adjusted quarterly average assets), Ratio (as a percent)	0.040
Minimum Regulatory Requirements including Capital Conservation Buffer
Total capital (to risk-weighted assets), Ratio (as a percent)	10.50%
Tier I capital (to risk-weighted assets), Ratio (as a percent)	8.50%
CET1 capital (to risk-weighted assets), Ratio (as a percent)	7.00%
Tier 1 leverage capital (to adjusted quarterly average assets), Ratio (as a percent)	4.00%
Well-Capitalized Requirement
Total capital (to risk-weighted assets), Ratio (as a percent)	0.100
Tier I capital (to risk-weighted assets), Ratio (as a percent)	0.080
CET1 capital (to risk-weighted assets), Ratio (as a percent)	0.065
Tier 1 leverage capital (to adjusted quarterly average assets), Ratio (as a percent)	0.050