Note 15 - Income Taxes - Components of Income Tax Provision (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Federal									$ 10,048	$ 9,603	$ 7,201
State									1,643	1,554	1,233
Total current tax expense									11,691	11,157	8,434
Federal									(1,266)	(152)	296
State									(239)	(11)	52
Total deferred tax expense (benefit)									(1,505)	(163)	348
Total income tax expense	$ 3,389	$ 2,332	$ 2,270	$ 2,195	$ 2,833	$ 2,580	$ 2,951	$ 2,630	$ 10,186	$ 10,994	$ 8,782