Note 14 - Income Taxes - Summary of Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Federal	$ 47,547	$ 41,737	$ 32,102
State	1,798	1,374	323
Total current	49,345	43,111	32,425
Federal	(2,755)	37,398	10,960
State	6,484	7,388	5,185
Total deferred	3,729	44,787	16,145
Provision for income taxes	$ 53,074	$ 87,897	$ 48,570