Condensd Consolidated Statements of Operations and Comprehensive Income (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Interest and Dividend Income
Loans receivable, including loan fees	$ 88,840	$ 90,701
Investment securities- taxable	11,786	17,723
Investment securities- nontaxable	967	1,052
Federal Home Loan Bank stock	250	66
Federal funds sold and securities purchased under agreements to resell		5
Deposits with banks	208	588
Total interest and dividend income	102,051	110,135
Interest Expense
Time deposits of $100,000 or more	6,757	9,540
Other deposits	2,766	3,916
Securities sold under agreements to repurchase	11,392	14,655
Advances from Federal Home Loan Bank	80	53
Long-term debt	924	1,320
Short-term borrowings	0	0
Total interest expense	21,919	29,484
Net interest income before provision for credit losses	80,132	80,651
Provision/(credit) for loan losses		(4,000)
Net interest income after provision for loan losses	80,132	84,651
Non-Interest Income
Securities gains, net	6,292	2,215
Letters of credit commissions	1,461	1,526
Depository service fees	1,474	1,389
Other operating income	5,654	3,701
Total non-interest income	14,881	8,831
Non-interest Expense
Salaries and employee benefits	22,853	19,878
Occupancy expense	3,644	3,584
Computer and equipment expense	2,676	2,463
Professional services expense	5,817	4,742
FDIC and State assessments	1,738	2,489
Marketing expense	437	1,406
Other real estate owned expense	623	4,693
Operations of affordable housing investments, net	1,695	1,960
Amortization of core deposit intangibles	1,396	1,457
Costs associated with debt redemption	5,645	2,750
Other operating expense	2,604	2,449
Total non-interest expense	49,128	47,871
Income before income tax expense	45,885	45,611
Income tax expense	16,887	16,547
Net income	28,998	29,064
Less: net income attributable to noncontrolling interest	151	151
Net income attributable to Cathay General Bancorp	28,847	28,913
Dividends on preferred stock and noncash charge from repayment	(5,184)	(4,117)
Net income attributable to common stockholders	23,663	24,796
Other comprehensive income, net of tax
Unrealized holding gain arising during the period	26,659	5,479
Less: reclassification adjustments included in net income	3,647	1,284
Total other comprehensive gain, net of tax	23,012	4,195
Total comprehensive income	$ 51,859	$ 33,108
Net income per common share:
Basic (in Dollars per share)	$ 0.30	$ 0.32
Diluted (in Dollars per share)	$ 0.30	$ 0.32
Cash dividends paid per common share (in Dollars per share)	$ 0.01	$ 0.01
Average common shares outstanding
Basic (in Shares)	78,795,564	78,678,645
Diluted (in Shares)	78,815,141	78,690,132