Note 13 - Income Taxes - Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Income tax expense at U.S. federal statutory rate	$ 59,172	$ 65,565	$ 15,217
Limited tax benefit due to wage and stock-based compensation	3,811	7,362	(51)
State deferred income taxes	2,903	2,335	1,730
Other	19	99	8
Total income tax expense	$ 65,905	$ 75,361	$ 16,904
Effective income tax rate	23.40%	24.10%	23.30%