Note 16 - Income Taxes - Reconciliation of Federal Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Expense computed at federal tax rate	$ 21,765	$ 14,186	$ 11,999
Expense computed at federal tax rate, percent	21.00%	21.00%	21.00%
Stock-based compensation and Section 162(m)	$ 1,523	$ 153	$ (1,067)
Stock-based compensation and Section 162(m)	1.47%	0.23%	(1.87%)
Dividend received deduction and tax-exempt interest	$ (96)	$ (101)	$ (81)
Dividend received deduction and tax-exempt interest, percent	(0.09%)	(0.15%)	(0.14%)
Meals & entertainment, penalties & parking	$ 261	$ 180	$ 91
Meals & entertainment, penalties & parking, percent	0.25%	0.27%	0.16%
State tax expense (benefit)	$ 303	$ 773	$ (1,750)
State tax expense (benefit)	0.29%	1.14%	(3.06%)
Valuation allowance	$ 416	$ 191	$ 2,199
Valuation allowance, percent	0.40%	0.28%	3.85%
Other	$ 269	$ (1)	$ (101)
Other, percent	0.26%	0.00%	(0.18%)
Income tax expense (benefit)	$ 24,441	$ 15,381	$ 11,291
Income tax expense (benefit), percent	23.58%	22.77%	19.76%