Note 6 - Income Taxes (Details Textual) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Percent	39.40%	13.20%
Effective Income Tax Rate Reconciliation, Excluding Equity Compensation and Acquisition Costs and Deferred Adjustments, Percent	38.60%
Unrecognized Tax Benefits	$ 7.9		$ 7.4
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0.7		$ 0.6
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	0.1	$ 0.3
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 0.6