Note 5 - Income Taxes - Components of Income Tax Expense (Benefit) from Operations (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Federal	$ 4,722	$ 4,222	$ 7,725	$ 6,595
State	179	186	293	310
Total current income tax expense	4,901	4,408	8,018	6,905
Federal	(631)	(711)	(657)	390
State	(24)	(21)	14	57
Total deferred income tax expense (benefit)	(655)	(732)	(643)	447
Change in valuation allowance	113		126
Total income tax expense	$ 4,359	$ 3,676	$ 7,501	$ 7,352