Note 10 - Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal									$ 20,943	$ 26,820	$ 59,433
State									39,466	36,639	28,278
Total Current									60,409	63,459	87,711
Deferred:
Federal									7,464	1,495	31,818
State									2,361	848	2,736
Total Deferred									9,825	2,343	34,554
Total income tax expense	$ 16,290	$ 20,973	$ 14,383	$ 18,588	$ 17,193	$ 18,698	$ 11,046	$ 18,866	$ 70,234	$ 65,802	$ 122,265