Note 7 - Derivatives and Hedging Activities - Hedged Interest Rate Swaps and Non-hedged Interest Rate Swaps (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Swapped loan portfolio loan-to-value percentage, including the potential swap exposure	65.00%
Interest rate swap
Derivative [Line Items]
Interest rate swaps collateralized by investment securities	$ 38,756	$ 228,925
Interest rate swap | Cash
Derivative [Line Items]
Interest rate swaps collateralized by investment securities	1,272	21,100
Interest rate swap | U.S. govt. sponsored agency securities.
Derivative [Line Items]
Interest rate swaps collateralized by investment securities		3,555
Interest rate swap | Municipal securities
Derivative [Line Items]
Interest rate swaps collateralized by investment securities	8,227	139,166
Interest rate swap | Residential mortgage-backed and related securities
Derivative [Line Items]
Interest rate swaps collateralized by investment securities	$ 29,257	$ 65,104