Note 5 - Income Taxes - Components of Income Tax Expense (Benefit) from Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Federal	$ 5,211	$ 4,363	$ 12,936	$ 10,958
State	179	287	472	597
Total current income tax expense	5,390	4,650	13,408	11,555
Federal	(1,583)	(692)	(2,240)	(302)
State	(44)	(75)	(30)	(18)
Total deferred income tax expense (benefit)	(1,627)	(767)	(2,270)	(320)
Change in valuation allowance	333		459
Total income tax expense	$ 4,096	$ 3,883	$ 11,597	$ 11,235