Note 11 - Capital Resources - Outstanding Junior Subordinated Notes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	May 31, 2014
Junior subordinated debt	$ 119,136	$ 119,136	$ 119,100
Cathay Capital Trust I [Member]
Junior subordinated debt	$ 20,619	$ 20,619
current interest rate	8.81%	6.82%
coupon rate		3.15%
Cathay Capital Trust I [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
coupon rate	3.15%
Cathay Statutory Trust I [Member]
Junior subordinated debt	$ 20,619	$ 20,619
current interest rate	8.67%	6.53%
coupon rate		3.00%
Cathay Statutory Trust I [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
coupon rate	3.00%
Cathay Capital Trust II [Member]
Junior subordinated debt	$ 12,887	$ 12,887
current interest rate	8.56%	6.57%
coupon rate		2.90%
Cathay Capital Trust II [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
coupon rate	2.90%
Cathay Capital Trust III [Member]
Junior subordinated debt	$ 46,392	$ 46,392
current interest rate	7.15%	4.77%
coupon rate		1.48%
Cathay Capital Trust III [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
coupon rate	1.48%
Cathay Capital Trust IV [Member]
Junior subordinated debt	$ 18,619	$ 18,619
current interest rate	7.06%	4.54%
coupon rate		1.40%
Cathay Capital Trust IV [Member] | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate [Member]
coupon rate	1.40%