Note 4 - Loans and the Allowance for Credit Losses - Composition of Loan Portfolio (Details) - USD ($) $ in Thousands		Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, before Allowance for Credit Loss, Fee and Loan in Process		$ 8,109,161	$ 6,838,351
Net deferred fees		(9,472)	(9,729)
Loans receivable		8,099,689	6,828,622
Commercial Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss, Fee and Loan in Process	[1]	1,472,734	1,299,428
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss, Fee and Loan in Process		5,795,228	4,741,590
Commercial Construction Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss, Fee and Loan in Process		574,139	540,178
Residential Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss, Fee and Loan in Process		264,748	255,269
Consumer Portfolio Segment [Member]
Financing Receivable, before Allowance for Credit Loss, Fee and Loan in Process		$ 2,312	$ 1,886

[1] Included in commercial loans as of December 31, 2022 and December 31, 2021 were Paycheck Protection Program (“PPP”) loans of $11.4 million and $93.1 million, respectively. These loans are 100% federally guaranteed and currently not subject to any allocation of allowance for credit losses.