Note 14 - Commitments and Contingencies - Financial Instruments With Off-balance Sheet Risk (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Commitments	$ 4,188,545	$ 3,975,541
Commitments to Extend Credit [Member]
Commitments	3,808,619	3,630,304
Standby Letters of Credit [Member]
Commitments	368,618	315,821
Commercial Letters of Credit [Member]
Commitments	$ 11,308	$ 29,416

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

No definition available.

Name:	us-gaap_OtherCommitment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant