Note 6 - Income Taxes - Components of Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ (1,210)	$ 7,575	$ 12,427
State	1,782	3,076	990
Total current	572	10,651	13,417
Deferred:
Federal	15,572	5,815	(48,424)
State	473	(464)	1,196
Total deferred	16,045	5,351	(47,228)
Total expense (benefit)	$ 16,617	$ 16,002	$ (33,811)