Note 1 - Summary of Significant Accounting Policies - Advertising Expense and Manufacturing Cooperative Advertising Credits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Advertising expense, gross	$ 101,656	$ 89,736	$ 62,933
Manufacturer cooperative advertising credits	(20,293)	(19,801)	(16,281)
Advertising expense, net	$ 81,363	$ 69,935	$ 46,652