Note 5 - Goodwill and Franchise Value - Goodwill (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015
Balance	[1]	$ 213,220	$ 199,375
Additions through acquisitions		47,397	14,091
Reductions through divestitures		(1,218)	(246)
Balance	[1]	259,399	213,220
Domestic [Member]
Balance	[1]	97,903	91,011
Additions through acquisitions		18,154	6,892
Reductions through divestitures		(1,218)
Balance	[1]	114,839	97,903
Import [Member]
Balance	[1]	84,384	79,601
Additions through acquisitions		21,795	5,029
Reductions through divestitures			(246)
Balance	[1]	106,179	84,384
Luxury [Member]
Balance	[1]	30,933	28,763
Additions through acquisitions		7,448	2,170
Reductions through divestitures
Balance	[1]	$ 38,381	$ 30,933

[1] Net of accumulated impairment losses of $299.3 million recorded during the year ended December 31, 2008.