Note 8 - Dividends (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended											4 Months Ended	12 Months Ended
	Oct. 31, 2021	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Oct. 31, 2021	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Common Stock, Dividends, Per Share, Declared														$ 0.24	$ 0.24	$ 0.66
Payments of Ordinary Dividends, Common Stock														$ 19,509	$ 19,563	$ 54,735
Paid Quarterly [Member]
Common Stock, Dividends, Per Share, Declared		$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.04	$ 0.04	$ 0.04	$ 0.04
Payments of Ordinary Dividends, Common Stock														$ 19,500	$ 19,600	$ 54,700
Special Dividend [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.5