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Note 9 - Loans - Components of Loans in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Loans	$ 17,787,888		$ 16,342,479
Less: Allowance for loan losses	(148,772)	$ (145,786)	(136,157)	$ (131,256)	$ (145,110)	$ (166,538)
Unamortized deferred loan fees, net	(5,540)		(4,321)
Loans, net	17,633,576		16,202,001
Commercial Portfolio Segment [Member]
Loans	3,194,509		2,982,399
Less: Allowance for loan losses	(49,071)	(44,738)	(43,394)	(40,067)	(42,034)	(68,742)
Real Estate Construction Portfolio Segment [Member]
Loans	602,052		611,031
Less: Allowance for loan losses	(7,276)	(7,436)	(6,302)	(6,119)	(6,992)	(30,854)
Commercial Real Estate Portfolio Segment [Member]
Loans	8,563,001		8,143,272
Less: Allowance for loan losses	(68,600)	(63,878)	(61,081)	(58,026)	(65,347)	(49,205)
Residential Portfolio Segment [Member]
Loans	5,045,383		4,182,006
Equity Lines Portfolio Segment [Member]
Loans	377,009		419,487
Installment and Other Loans [Member ]
Loans	5,934		4,284
Less: Allowance for loan losses	$ (134)	$ (104)	$ (1)	$ (1)	$ (3)	$ 0