Note 7 - Investment Securities (Details Textual) $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2023 USD ($)	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-Sale, Accrued Interest, after Allowance for Credit Loss		$ 4,800
Equity Securities, FV-NI, Unrealized Gain (Loss)		(9,026)	$ 4,853
Equity Securities, FV-NI, Current	$ 40,400	$ 31,380	40,400	$ 40,406
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions		200		192
Proceeds from Sale of Debt Securities, Available-for-Sale		$ 33,690	$ 0
Debt Securities, Available-for-Sale, Allowance for Credit Loss		0
Debt Securities, Available-for-Sale, Transfer in, Allowance for Credit Loss, Expense		0
Pledged Investment Securities		30,600		$ 134,200
Signature Bank [Member]
Debt Securities, Available-for-Sale, Realized Loss	$ 3,000
Proceeds from Sale of Debt Securities, Available-for-Sale		$ 1,400
Collateralized Mortgage-Backed Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions		156		154
Corporate Debt Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions		23		24
US Treasury Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions		8		1
Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions		5		5
US Government Corporations and Agencies Securities [Member]
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions		5		8