Note 1 - Business and Significant Accounting Policies - Cash and Restricted Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash and cash equivalents	$ 195,808	$ 95,872	$ 239,278
Restricted cash and cash equivalents	91,962	130,804	104,166
Total cash and cash equivalents and restricted cash and cash equivalents	$ 287,770	$ 226,676	$ 343,444	$ 536,778