Note 8 - Income Taxes (Details) - Components of Income Tax Expense (Benefit) from Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current tax expense
Federal	$ 15,478	$ 14,958	$ 10,322
State	608	641	336
Total current tax expense	16,086	15,599	10,658
Deferred tax expense (benefit)
Federal	748	(385)	450
State	54	26	120
Total deferred tax expense (benefit)	847	(318)	570
Change in valuation allowance	45	41	0
Total income tax expense	$ 16,933	$ 15,281	$ 11,228