Note 12 - Income Taxes - Income Tax Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Tax provision at Federal statutory rate, amount	$ 99,233	$ 80,187	$ 53,333
Tax provision at Federal statutory rate, percent	21.00%	21.00%	21.00%
State income taxes, net of Federal income tax benefit, amount	$ 44,837	$ 37,602	$ 23,602
State income taxes, net of Federal income tax benefit, percent	9.50%	9.80%	9.30%
Excess deduction for stock option and RSUs, amount	$ (140)	$ (20)	$ 264
Excess deduction for stock option and RSUs, percent	0.00%	0.00%	0.10%
Low income housing and other tax credits, amount	$ (34,231)	$ (32,795)	$ (52,979)
Low income housing and other tax credits, percent	(7.20%)	(8.60%)	(20.80%)
Other, net, amount	$ 2,195	$ (1,435)	$ 885
Other, net, percent	0.40%	(0.30%)	0.30%
Total income tax expense, amount	$ 111,894	$ 83,539	$ 25,105
Total income tax expense, percent	23.70%	21.90%	9.90%