Note 13 - Fair Value Measurements (Details Textual) $ in Thousands	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Debt Securities, Available-for-Sale, Amortized Cost	$ 493,360	$ 501,402
Debt Securities, Available-for-Sale	$ 442,120	450,814
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale, Number of Securities	30
Debt Securities, Available-for-Sale, Amortized Cost	$ 35,050	35,055
Debt Securities, Available-for-Sale	$ 31,564	$ 31,286
Inactive Corporate Debt Securities [Member]
Debt Securities, Available-for-sale, Number of Securities	4
Debt Securities, Available-for-Sale, Amortized Cost	$ 8,000
Debt Securities, Available-for-Sale	$ 7,100