Consolidated Statements of Operations and Comprehensive Income (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
INTEREST AND DIVIDEND INCOME
Loan receivable	$ 359,959	$ 360,643	$ 364,580
Investment securities- taxable	43,412	62,395	83,083
Investment securities- nontaxable	995	4,161	4,218
Federal Home Loan Bank stock	1,480	485	177
Federal funds sold and securities purchased under agreement to resell		18	83
Deposits with banks	1,150	2,042	1,430
Total interest and dividend income	406,996	429,744	453,571
INTEREST EXPENSE
Time deposits of $100,000 or more	27,211	33,441	42,204
Other deposits	13,178	13,932	20,010
Interest on securities sold under agreements to repurchase	37,692	55,699	60,733
Advances from the Federal Home Loan Bank	528	270	12,033
Long-term debt	3,691	5,149	4,890
Short-term borrowings			11
Total interest expense	82,300	108,491	139,881
Net interest income before provision for credit losses	324,696	321,253	313,690
(Reversal)/provision for credit losses	(3,000)	(9,000)	27,000
Net interest income after provision for credit losses	327,696	330,253	286,690
NON-INTEREST INCOME
Securities gains, net	27,362	18,026	21,131
Letters of credit commissions	6,281	6,316	5,644
Depository service fees	5,701	5,453	5,420
Other operating income	20,963	16,712	18,697
Total non-interest income	60,307	46,507	50,892
NON-INTEREST EXPENSE
Salaries and employee benefits	88,276	78,377	71,849
Occupancy expense	14,846	14,608	14,225
Computer and equipment expense	9,768	9,591	8,508
Professional services expense	24,574	21,768	20,209
FDIC and State assessments	7,351	8,339	12,494
Marketing expense	3,403	4,607	3,175
Other real estate owned (income)/expense	(235)	15,116	10,583
Operations of investments in affordable housing	7,253	6,306	8,153
Amortization of core deposit premium	4,533	5,663	5,859
Cost associated with debt redemption	22,557	12,120	20,231
Other operating expense	11,507	16,094	10,280
Total non-interest expense	193,833	192,589	185,566
Income before income tax expense	194,170	184,171	152,016
Income tax expense	70,435	66,128	51,261
Net income	123,735	118,043	100,755
Less: net income attributable to noncontrolling interest	592	605	605
Net income attributable to Cathay General Bancorp	123,143	117,438	100,150
Dividends on preferred stock	(9,685)	(16,488)	(16,437)
Net income attributable to common stockholders	113,458	100,950	83,713
Other comprehensive (loss)/income, net of tax:
Unrealized holding (losses)/gains arising during the year	(14,335)	19,645	4,538
Less: reclassification adjustment for gains included in net income	15,859	10,448	12,248
Total other comprehensive (loss)/income, net of tax	(30,194)	9,197	(7,710)
Total comprehensive income	$ 92,949	$ 126,635	$ 92,440
Net income attributable to common stockholders per common share
Basic (in Dollars per share)	$ 1.44	$ 1.28	$ 1.06
Diluted (in Dollars per share)	$ 1.43	$ 1.28	$ 1.06
Basic average common shares outstanding (in Shares)	78,954,898	78,719,133	78,633,317
Diluted average common shares outstanding (in Shares)	79,137,983	78,723,297	78,640,652