Note 13 - Income Taxes - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income taxes at the federal statutory rate	$ 23,255	$ 37,733	$ 45,691
State income taxes, net of federal benefit	1,552	3,053	3,398
Tax effect of permanent differences	887	959	1,069
Other, net	173	5	428
Provision (benefit) for income taxes	$ 25,867	$ 41,750	$ 50,586