Note 6 - Summary of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current tax expense:
Federal	$ 25,852	$ 20,244	$ 25,211
State	3,450	4,429	4,736
Total	29,302	24,673	29,947
Deferred tax expense (benefit):
Federal	(12,571)	(12,421)	(3,485)
State	(1,449)	131	(869)
Total	(14,020)	(12,290)	(4,354)
Total income tax expense	$ 15,282	$ 12,383	$ 25,593