Note 5 - Income Taxes (Details Textual) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Effective Income Tax Rate Reconciliation, Percent	26.70%	32.00%	24.50%	31.40%
Income Tax Expense (Benefit)	$ 9,174	$ 9,789	$ 14,986	$ 16,341
Effective Income Tax Rate, Continuing Operations Before ASU Adoption			31.60%
Accounting Standards Update 2016-09 [Member]
Effective Income Tax Rate Reconciliation, Percent			(7.10%)
Income Tax Expense (Benefit)			$ (4,379)