Note 3 - Recent Accounting Pronouncements (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2021	Jan. 01, 2021	Dec. 31, 2020
Retained Earnings (Accumulated Deficit), Ending Balance	$ 1,837,261		$ 1,789,325
Loans and Leases Receivable, Allowance, Ending Balance	$ 147,264		166,538
Off-Balance Sheet, Credit Loss, Liability, Ending Balance			$ 5,880
Accounting Standards Update 2016-13 [Member]
Retained Earnings (Accumulated Deficit), Ending Balance		$ (800)
Loans and Leases Receivable, Allowance, Ending Balance		600
Off-Balance Sheet, Credit Loss, Liability, Ending Balance		$ 500