Note 2 - Investment Securities - Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022
Due within one year, AFS, amortized cost	$ 37,631
Due within one year, AFS, fair value	37,337
Due within one year, HTM, carrying value		$ 51,134
Due within one year, HTM, fair value		49,821
Due after one year but within five years, AFS, amortized cost	155,874
Due after one year but within five years, AFS, fair value	147,197
Due after one year but within five years, HTM, carrying value		153,477
Due after one year but within five years, HTM, fair value		146,073
Due after five years but within 10 years, AFS, amortized cost	69,673
Due after five years but within 10 years, AFS, fair value	61,354
Due after five years but within 10 years, HTM, carrying value		25,955
Due after five years but within 10 years, HTM, fair value		23,049
Due after 10 years, AFS, amortized cost	145,204
Due after 10 years, AFS, fair value	134,124
Due after 10 years, HTM, carrying value		578
Due after 10 years, HTM, fair value		568
Mortgage-backed securities – government agencies, AFS, amortized cost	829,867
Mortgage-backed securities – government agencies, AFS, fair value	712,712
Mortgage backed securities - government agencies, HTM, carrying value		218,885
Mortgage backed securities - government agencies, HTM, fair value		190,738
Total available for sale debt securities, amortized cost	1,238,249		$ 1,297,977
Total available for sale debt securities, fair value	1,092,724		1,144,617
Total held to maturity debt securities, carrying value		450,029
Total held to maturity debt securities, fair value	$ 410,249	$ 410,249	$ 431,833