Note 21 - Regulatory Matters (Tables)

12 Months Ended

Dec. 31, 2017

Notes Tables

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

	Cathay General Bancorp								Cathay Bank
	December 31, 2017				December 31, 2016				December 31, 2017				December 31, 2016
(Dollars in thousands)	Balance		%		Balance		%		Balance		%		Balance		%
Common equity Tier 1 capital ( to risk-weighted assets)	$	1,572,025		12.19	$	1,459,351		12.84	$	1,734,719		13.46	$	1,515,096		13.35
Common equity Tier 1 capital minimum requirement		580,552		4.50		511,590		4.50		579,921		4.50		510,582		4.50
Excess	$	991,473		7.69	$	947,761		8.34	$	1,154,798		8.96	$	1,004,514		8.85
Tier 1 capital (to risk-weighted assets)	$	1,572,025		12.19	$	1,574,806		13.85	$	1,734,719		13.46	$	1,515,096		13.35
Tier 1 capital minimum requirement		774,070		6.00		682,120		6.00		773,229		6.00		680,776		6.00
Excess	$	797,955		6.19	$	892,686		7.85	$	961,490		7.46	$	834,320		7.35
Total capital (to risk-weighted assets)	$	1,820,860		14.11	$	1,702,144		14.97	$	1,862,806		14.45	$	1,637,286		14.43
Total capital minimum requirement		1,032,093		8.00		909,493		8.00		1,030,971		8.00		907,701		8.00
Excess	$	788,767		6.11	$	792,651		6.97	$	831,835		6.45	$	729,585		6.43
Tier 1 capital (to average assets) – Leverage ratio	$	1,572,025		10.35	$	1,574,806		11.57	$	1,734,719		11.82	$	1,515,096		11.16
Minimum leverage requirement		607,349		4.00		544,614		4.00		586,959		4.00		543,059		4.00
Excess	$	964,676		6.35	$	1,030,192		7.57	$	1,147,760		7.82	$	972,037		7.16
Risk-weighted assets	$	12,901,161			$	11,368,663			$	12,887,142			$	11,346,260
Total average assets (1)	$	15,183,720			$	13,615,348			$	14,673,981			$	13,576,477