Note 3 - Securities - Securities in a Continuous Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Temporarily impaired securities, less than 12 months, fair value	$ 266,414	$ 69,967
Temporarily impaired securities, less than 12 months unrealized loss	4,922	498
Temporarily impaired securities, 12 months or more fair value	51,999	4,695
Temporarily impaired securities, 12 months or more unrealized loss	2,145	5
US Government Agencies Debt Securities [Member]
Temporarily impaired securities, less than 12 months, fair value	201,650	28,798
Temporarily impaired securities, less than 12 months unrealized loss	3,530	173
Temporarily impaired securities, 12 months or more fair value	26,792	0
Temporarily impaired securities, 12 months or more unrealized loss	1,180	0
US States and Political Subdivisions Debt Securities [Member]
Temporarily impaired securities, less than 12 months, fair value	50,659	32,353
Temporarily impaired securities, less than 12 months unrealized loss	1,214	249
Temporarily impaired securities, 12 months or more fair value	20,542	635
Temporarily impaired securities, 12 months or more unrealized loss	793	3
Commercial Mortgage Backed Securities [Member]
Temporarily impaired securities, less than 12 months, fair value	13,139	8,816
Temporarily impaired securities, less than 12 months unrealized loss	141	76
Temporarily impaired securities, 12 months or more fair value	4,665	4,060
Temporarily impaired securities, 12 months or more unrealized loss	172	$ 2
Corporate Debt Securities [Member]
Temporarily impaired securities, less than 12 months, fair value	966
Temporarily impaired securities, less than 12 months unrealized loss	37
Temporarily impaired securities, 12 months or more fair value	0
Temporarily impaired securities, 12 months or more unrealized loss	$ 0