Note 6 - Income Taxes (Details Textual) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Taxes [Member]
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 0.2
Effective Income Tax Rate Reconciliation, Percent	42.00%	41.70%
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 1.9	$ 1.4
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	0.6	$ 0.3
Decrease in Unrecognized Tax Benefits is Reasonably Possible	$ 1.6