Note 6 - Credit Facilities and Long-term Debt - Credit Facilities and Long-term Debt (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
New vehicle floor plan commitment	$ 1,506,895	$ 1,265,872
Floor plan notes payable	94,602	48,083
Total floor plan debt	1,601,497	1,313,955
Real estate mortgages	428,367	387,861
Other debt	11,191	25,248
Debt issuance costs	(2,184)	(2,169)
Total debt	2,392,378	1,957,141
Used Vehicle Inventory Financing [Member]
Long-term Line of Credit	211,000	171,000
Revolving Credit Facility [Member]
Long-term Line of Credit	$ 142,507	$ 61,246