Note 9 - Loans - Components of Loans in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021
Loans	$ 18,952,794		$ 18,254,024
Less: Allowance for loan losses	(155,109)	$ (144,884)	(146,485)	$ (148,772)	$ (145,786)	$ (136,157)
Unamortized deferred loan fees, net	(9,497)		(6,641)
Loans, net	18,788,188		18,100,898
Commercial Portfolio Segment [Member]
Loans	3,317,868		3,318,778
Less: Allowance for loan losses	(50,579)	(45,975)	(49,435)	(49,071)	(44,738)	(43,394)
Real Estate Construction Portfolio Segment [Member]
Loans	521,673		559,372
Less: Allowance for loan losses	(12,751)	(10,900)	(10,417)	(7,276)	(7,436)	(6,302)
Commercial Real Estate Portfolio Segment [Member]
Loans	9,293,475		8,793,685
Less: Allowance for loan losses	(73,547)	(70,367)	(68,366)	(68,600)	(63,878)	(61,081)
Residential Portfolio Segment [Member]
Loans	5,542,466		5,252,952
Equity Lines Portfolio Segment [Member]
Loans	272,055		324,548
Installment and Other Loans [Member ]
Loans	5,257		4,689
Less: Allowance for loan losses	$ (18)	$ (9)	$ (35)	$ (134)	$ (104)	$ (1)