Note 9 - Loans - Components of Loans in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Loans	$ 18,317,339	$ 18,254,024
Less: Allowance for loan losses	(144,884)	(146,485)	$ (145,786)	$ (136,157)
Unamortized deferred loan fees, net	(5,872)	(6,641)
Loans, net	18,166,583	18,100,898
Commercial Portfolio Segment [Member]
Loans	3,153,039	3,318,778
Less: Allowance for loan losses	(45,975)	(49,435)	(44,738)	(43,394)
Real Estate Construction Portfolio Segment [Member]
Loans	558,967	559,372
Less: Allowance for loan losses	(10,900)	(10,417)	(7,436)	(6,302)
Commercial Real Estate Portfolio Segment [Member]
Loans	8,916,766	8,793,685
Less: Allowance for loan losses	(70,367)	(68,366)	(63,878)	(61,081)
Residential Portfolio Segment [Member]
Loans	5,384,220	5,252,952
Equity Lines Portfolio Segment [Member]
Loans	298,630	324,548
Installment and Other Loans [Member ]
Loans	5,717	4,689
Less: Allowance for loan losses	$ (9)	$ (35)	$ (104)	$ (1)