Note 8 - Income Taxes - Summary of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current tax expense:
Federal	$ 2,965	$ 17,008	$ 16,274
State	(1,433)	3,201	2,929
Total current tax expense:	1,532	20,209	19,203
Deferred tax expense (benefit):
Federal	(2,650)	(19,425)	(7,115)
State	(854)	(983)	(253)
Total deferred tax benefit:	(3,504)	(20,408)	(7,368)
Total income tax expense (benefit)	$ (1,972)	$ (199)	$ 11,835