Note 7 - Income Taxes - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
Federal	$ 7,575	$ 12,427	$ 8,987
State	3,076	990	1,125
Total current	10,651	13,417	10,112
Deferred:
Federal	5,815	(48,424)	12,427
State	(464)	1,196	1,063
Total deferred	5,351	(47,228)	13,490
Total expense (benefit)	$ 16,002	$ (33,811)	$ 23,602