Note 12 - Commitments and Contingencies - Financial Instruments With Off-balance Sheet Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Commitments	$ 3,580,504	$ 3,228,787
Commitments to Extend Credit [Member]
Commitments	3,297,362	2,977,528
Standby Letters of Credit [Member]
Commitments	266,490	234,200
Commercial Letters of Credit [Member]
Commitments	16,652	16,821
Bill of Lading Guarantees [Member]
Commitments	$ 0	$ 238