Note 19 - Segments - Certain Segment Financial Information (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Total revenues		$ 8,678,157	$ 7,864,252	$ 5,390,326
Income from continuing operations before income taxes		283,523	262,704	210,495
Depreciation and amortization		(49,369)	(41,600)	(26,363)
Other interest expense		(23,207)	(19,491)	(10,742)
Other (expense) income, net		(6,103)	(1,006)	3,199
Floor plan interest expense:
Floor plan interest		25,531	19,534	13,861
Operating Segments [Member]
Total revenues		8,674,730	7,860,464	5,386,363
Income from continuing operations before income taxes	[1]	247,881	250,287	173,206
Floor plan interest expense:
Floor plan interest		56,109	45,116	32,390
Operating Segments [Member] | Domestic [Member]
Total revenues		3,381,715	3,038,883	2,569,928
Income from continuing operations before income taxes	[1]	106,210	115,145	96,608
Floor plan interest expense:
Floor plan interest		26,445	21,061	17,895
Operating Segments [Member] | Import [Member]
Total revenues		3,764,255	3,330,949	1,889,579
Income from continuing operations before income taxes	[1]	110,204	98,751	51,150
Floor plan interest expense:
Floor plan interest		18,665	14,959	9,397
Operating Segments [Member] | Luxury [Member]
Total revenues		1,528,760	1,490,632	926,856
Income from continuing operations before income taxes	[1]	31,467	36,391	25,448
Floor plan interest expense:
Floor plan interest		10,999	9,096	5,098
Corporate, Non-Segment [Member]
Total revenues		3,427	3,788	3,963
Income from continuing operations before income taxes	[1]	114,321	74,514	71,195
Floor plan interest expense:
Floor plan interest		$ (30,578)	$ (25,582)	$ (18,529)

[1] Segment income for each of the segments is defined as Income from continuing operations before income taxes, depreciation and amortization, other interest expense and other (expense) income, net.