Note 15 - Fair Value Measurements - Assets and Liabilities at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Securities available for sale	$ 686,080	$ 546,742
Fair Value, Inputs, Level 2 [Member]
Securities available for sale	686,080	546,742
US Government Agencies Debt Securities [Member]
Securities available for sale	278,019	91,163
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available for sale	278,019	91,163
US States and Political Subdivisions Debt Securities [Member]
Securities available for sale	198,672	203,961
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available for sale	198,672	203,961
Collateralized Mortgage Backed Securities [Member]
Securities available for sale	206,174	249,175
Collateralized Mortgage Backed Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available for sale	206,174	249,175
Corporate Debt Securities [Member]
Securities available for sale	3,215	2,443
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Securities available for sale	$ 3,215	$ 2,443