Note 6 - Income Taxes - Components of Income Tax Expense (Benefit) from Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Current income tax expense:
Federal	$ 3,369	$ 4,524	$ 9,574	$ 11,022
State	198	224	538	554
Total current income tax expense	3,567	4,748	10,112	11,576
Deferred income tax expense (benefit):
Federal	(1,507)	(768)	(2,653)	21
State	(476)	(201)	(1,279)	(4,969)
Total deferred income tax expense (benefit)	(1,983)	(969)	(3,932)	(4,948)
Change in valuation allowance	7	4	9	24
Total income tax expense	$ 1,591	$ 3,783	$ 6,189	$ 6,652