Note 22 - Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure Text Block [Abstract]

Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]

	Cathay General Bancorp								Cathay Bank
	December 31, 2015				December 31, 2014				December 31, 2015				December 31, 2014
(Dollars in thousands)	Balance		%		Balance		%		Balance		%		Balance		%
Common equtiy Tier 1 capital ( to risk-weighted assets)	$	1,383,377		12.95		n/a		n/a	$	1,443,159		13.54		n/a		n/a
Common equtiy Tier 1 capital minimum requirement		480,830		4.50		n/a		n/a		479,801		4.50		n/a		n/a
Excess	$	902,547		8.45		n/a		n/a	$	963,358		9.04		n/a		n/a
Tier 1 capital (to risk-weighted assets)	$	1,498,810		14.03	$	1,406,511		14.96	$	1,443,159		13.54	$	1,353,481		14.42
Tier 1 capital minimum requirement		641,107		6.00		376,072		4.00		639,735		6.00		375,318		4.00
Excess	$	857,703		8.03	$	1,030,439		10.96	$	803,424		7.54	$	978,163		10.42
Total capital (to risk-weighted assets)	$	1,634,631		15.30	$	1,524,702		16.22	$	1,576,525		14.79	$	1,471,337		15.68
Total capital minimum requirement		854,809		8.00		752,144		8.00		852,980		8.00		750,637		8.00
Excess	$	779,822		7.30	$	772,558		8.22	$	723,545		6.79	$	720,700		7.68
Tier 1 capital (to average assets)
– Leverage ratio	$	1,498,810		11.95	$	1,406,511		12.99	$	1,443,159		11.53	$	1,353,481		12.52
Minimum leverage requirement		501,875		4.00		433,121		4.00		500,455		4.00		432,350		4.00
Excess	$	996,935		7.95	$	973,390		8.99	$	942,704		7.53	$	921,131		8.52
Risk-weighted assets	$	10,685,115			$	9,401,803			$	10,662,248			$	9,382,961
Total average assets (1)	$	12,546,879			$	10,828,015			$	12,511,382			$	10,808,747