Note 13 - Income Taxes - Income Tax Expense (Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current provision-
Federal	$ 22,443	$ 15,236	$ 7,513
State	4,030	2,300	2,592
Total current	26,473	17,536	10,105
Deferred provision-
Federal	(64,821)	8,260	29,561
State	2,618	71	2,084
Total deferred	(62,203)	8,331	31,645
Provision (benefit) for income taxes	$ (35,730)	$ 25,867	$ 41,750