Note 4 - Investment Securities - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Due within one year, AFS, amortized cost	$ 128,053
Due within one year, AFS, fair value	124,318
Due within one year, HTM, carrying value	50,069
Due within one year, HTM, fair value	49,647
Due after one year but within five years, AFS, amortized cost	36,480
Due after one year but within five years, AFS, fair value	34,673
Due after one year but within five years, HTM, carrying value	153,931
Due after one year but within five years, HTM, fair value	149,393
Due after five years but within 10 years, AFS, amortized cost	81,862
Due after five years but within 10 years, AFS, fair value	72,415
Due after five years but within 10 years, HTM, carrying value	25,633
Due after five years but within 10 years, HTM, fair value	23,214
Due after 10 years, AFS, amortized cost	118,613
Due after 10 years, AFS, fair value	111,734
Due after 10 years, HTM, carrying value	544
Due after 10 years, HTM, fair value	534
Mortgage-backed securities – government agencies, AFS, amortized cost	789,145
Mortgage-backed securities – government agencies, AFS, fair value	688,039
Mortgage backed securities - government agencies, HTM, carrying value	209,660
Mortgage backed securities - government agencies, HTM, fair value	185,731
Total available for sale debt securities, amortized cost	1,154,153	$ 1,297,977
Total available for sale debt securities, fair value	1,031,179	1,144,617
Total held to maturity debt securities, carrying value	439,837
Total held to maturity debt securities, fair value	$ 408,519	$ 431,833