Note 2 - Impact of Recently Issued Accounting Pronouncements (Details Textual) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Unrecognized Excess Tax Benefits					$ 0
Income Tax Expense (Benefit)	$ 7,498	$ 5,443	$ 22,484	$ 21,784
Effective Income Tax Rate Reconciliation, Percent	30.30%	28.40%	26.10%	30.60%
Accounting Standards Update 2016-09 [Member]
Income Tax Expense (Benefit)			$ (5,114)
Effective Income Tax Rate Reconciliation, Percent			(6.00%)
Reclassification from Financing Activities to Operating Activities [Member] | Six Months Ended June 30, 2016 [Member]
Prior Period Reclassification Adjustment			$ 2,958