Note 5 - Loans and the Allowance for Credit Losses - Composition of Loan Portfolio (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Gross loans	$ 8,141,176	$ 8,109,161
Net deferred loan fees	(9,057)	(9,472)
Total loans receivable	8,132,119	8,099,689
Commercial Portfolio Segment [Member]
Gross loans	1,414,226	1,472,734
Commercial Real Estate Portfolio Segment [Member]
Gross loans	5,835,880	5,795,228
Commercial Construction Portfolio Segment [Member]
Gross loans	630,469	574,139
Residential Portfolio Segment [Member]
Gross loans	259,166	264,748
Consumer Portfolio Segment [Member]
Gross loans	$ 1,435	$ 2,312