Note 3 - Investment Securities - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Due within one year, AFS, amortized cost	$ 8,688
Due within one year, AFS, fair value	8,668
Due within one year, HTM, carrying value	60,025
Due within one year, HTM, fair value	60,024
Due after one year but within five years, AFS, amortized cost	160,345
Due after one year but within five years, AFS, fair value	154,123
Due after one year but within five years, HTM, carrying value	217,974
Due after one year but within five years, HTM, fair value	216,038
Due after five years but within 10 years, AFS, amortized cost	56,839
Due after five years but within 10 years, AFS, fair value	54,292
Due after five years but within 10 years, HTM, carrying value	26,679
Due after five years but within 10 years, HTM, fair value	26,515
Due after 10 years, AFS, amortized cost	179,491
Due after 10 years, AFS, fair value	173,859
Due after 10 years, HTM, carrying value	809
Due after 10 years, HTM, fair value	810
Mortgage-backed securities – government agencies, AFS, amortized cost	820,452
Mortgage-backed securities – government agencies, AFS, fair value	759,413
Mortgage backed securities - government agencies, HTM, carrying value	242,704
Mortgage backed securities - government agencies, HTM, fair value	232,420
Total available for sale debt securities, amortized cost	1,225,815	$ 1,190,379
Total available for sale debt securities, fair value	1,150,355	1,180,298
Total held to maturity debt securities, carrying value	548,191
Total held to maturity debt securities, fair value	$ 535,807	$ 0