Note 15 - Financial Derivatives (Details Textual) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2026	Dec. 31, 2025
Derivative Outstanding, Notional Amount	$ 1,120,000	$ 1,020,000
Derivative, Notional Amount	36,000	24,000
Margin Deposit Assets	39,700	12,100
Bank [Member]
Restricted Cash	1,200	4,300
Interest Rate Swap [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Central Counterparties (CCP) [Member]
Derivative, Notional Amount	0	0
Interest Rate Swap [Member] | Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivative, Notional Amount	522,904	$ 625,222
Interest Rate Contract [Member] | Cash Flow Hedging [Member] | Designated as Hedging Instrument [Member] | Central Counterparties (CCP) [Member]
Derivative Outstanding, Notional Amount	522,900
Derivative, Notional Amount	470,000
Derivative, Loss on Derivative	1,800
Interest Rate Contract [Member] | Fair Value Hedging [Member] | Designated as Hedging Instrument [Member]
Derivative Outstanding, Notional Amount	46,200
Derivative, Notional Amount	1,900
Loans Receivable with Partial-term Hedging Designation [Member]
Derivative, Notional Amount	681,900
Hedged Asset, Fair Value Hedge	476,700
Derivative, Gain on Derivative	$ 215