Note 6 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Expense (Benefit)	$ 5,812	$ 6,552
Effective Income Tax Rate Reconciliation, Percent	21.60%	30.60%
Effective Income Tax Rate, Continuing Operations Before ASU Adoption	31.40%
Accounting Standards Update 2016-09 [Member]
Income Tax Expense (Benefit)	$ (2,654)
Effective Income Tax Rate Reconciliation, Percent	(9.80%)