CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
REVENUES	$ 13,481.9	$ 10,600.2	$ 11,597.9
COST OF SALES	11,041.2	8,866.1	9,835.5
GROSS PROFIT	2,440.7	1,734.1	1,762.4
Selling, general and administrative expenses	1,477.2	1,138.2	1,312.4
Depreciation and amortization expense	77.4	73.5	70.0
Asset impairments	1.7	26.7	21.7
INCOME FROM OPERATIONS	884.4	495.7	358.3
INTEREST EXPENSE:
Floorplan interest expense	27.6	39.2	60.9
Other interest expense, net	55.8	61.9	74.8
Loss on extinguishment of debt	0.0	13.7	0.0
INCOME BEFORE INCOME TAXES	800.9	380.8	222.7
Provision for income taxes	175.5	84.2	53.7
Net income from continuing operations	625.4	296.7	169.0
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(73.3)	(10.2)	5.0
NET INCOME	$ 552.1	$ 286.5	$ 174.0
BASIC EARNINGS PER SHARE:
Basic earnings per share continuing operations (in dollars per shares)	$ 34.23	$ 16.11	$ 9.08
Basic earnings per share discontinuing operations (in dollars per shares)	(4.01)	(0.55)	0.27
Basic earnings per share (in dollars per shares)	30.22	15.55	9.35
DILUTED EARNINGS PER SHARE:
Diluted earnings per share continuing operations (in dollars per shares)	34.11	16.06	9.07
Diluted earnings per share discontinuing operations (in dollars per shares)	(4.00)	(0.55)	0.27
Diluted earnings per share (in dollars per shares)	$ 30.11	$ 15.51	$ 9.34
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
Weighted average common shares outstanding basic (in shares)	17,655,365	17,754,666	17,917,195
Weighted average common shares outstanding diluted (in shares)	17,722,212	17,806,578	17,936,075
New vehicle retail sales
REVENUES	$ 6,504.8	$ 5,428.4	$ 6,027.3
COST OF SALES	5,894.0	5,109.1	5,744.2
Used vehicle retail sales
REVENUES	4,438.8	3,055.6	3,281.2
COST OF SALES	4,084.6	2,850.7	3,085.8
Used vehicle wholesale sales
REVENUES	365.7	295.8	336.8
COST OF SALES	340.9	285.6	337.0
Parts and service sales
REVENUES	1,591.2	1,357.4	1,462.4
COST OF SALES	721.8	620.8	668.4
Finance, insurance and other, net
REVENUES	$ 581.4	$ 463.0	$ 490.2