Note 10 - Income Taxes - Reconciliation of Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income tax expense	$ 10,529	$ 797	$ 65,751	$ 19,109
Effective Income Tax Rate Reconciliation, Percent	40.70%	136.50%	40.60%	42.00%