Note 9 - Dividends (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended													12 Months Ended
	Dec. 31, 2020	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Oct. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Common Stock, Dividends, Per Share, Declared														$ 0.027	$ 0.24	$ 0.66	$ 0.633
Payments of Ordinary Dividends, Common Stock															$ 19,563	$ 54,735	$ 52,366
Paid Quarterly [Member]
Common Stock, Dividends, Per Share, Declared		$ 0.06	$ 0.06	$ 0.06	$ 0.06	$ 0.04		$ 0.04	$ 0.04	$ 0.04	$ 0.04	$ 0.04	$ 0.027
Payments of Ordinary Dividends, Common Stock															$ 19,600	$ 54,700	$ 52,400
Special Dividend [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.50						$ 0.50