PARENT COMPANY FINANCIAL STATEMENTS (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
STATEMENTS OF INCOME
Interest expense	$ 39,830	$ 44,959	$ 47,132	$ 45,501	$ 45,633	$ 48,595	$ 49,910	$ 56,979	$ 177,422	$ 201,117	$ 237,129
Compensation and net occupancy reimbursement to subsidiary									50,082	52,073	30,218
Other expense									60,383	67,879	37,380
Income before income taxes and equity in undistributed income of subsidiaries	103,339	97,685	95,730	86,580	85,706	73,527	58,734	37,942	383,334	255,909	104,722
Income tax benefit	(37,133)	(35,253)	(35,205)	(30,509)	(29,357)	(26,576)	(22,386)	(13,026)	(138,100)	(91,345)	(22,714)
NET INCOME AFTER EXTRAORDINARY ITEMS	66,206	62,432	60,525	56,071	56,349	46,951	36,348	24,916	245,234	164,564	76,642
East West Bancorp, Inc.
STATEMENTS OF INCOME
Dividends from subsidiaries									72,129	85,158	23,576
Interest income										1,095	794
Gain on sales of investment securities available-for-sale										556
Impairment write-down on investment securities available-for-sale											(5,863)
Impairment writedown on other investments											(581)
Other income									372	3
Total income									72,501	86,812	17,926
Interest expense									4,734	5,302	6,197
Compensation and net occupancy reimbursement to subsidiary									2,537	2,921	2,288
Other expense									2,339	2,132	1,179
Total expense									9,610	10,355	9,664
Income before income taxes and equity in undistributed income of subsidiaries									62,891	76,457	8,262
Income tax benefit									3,830	3,592	6,361
Equity in undistributed income (loss) of subsidiaries									178,513	84,515	62,019
NET INCOME AFTER EXTRAORDINARY ITEMS									$ 245,234	$ 164,564	$ 76,642