Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues:
Total revenues	$ 3,332.4	$ 3,092.0	$ 9,403.8	$ 8,848.2
Cost of sales:
Total cost of sales	2,821.5	2,625.8	7,948.6	7,513.1
Gross profit	510.9	466.2	1,455.2	1,335.1
Asset impairments	0.0	0.0	0.5	0.0
Selling, general and administrative	343.2	309.0	1,021.5	939.9
Depreciation and amortization	20.9	19.6	60.9	55.3
Operating income	146.8	137.6	372.3	339.9
Floor plan interest expense	(17.9)	(16.0)	(55.5)	(45.1)
Other interest expense, net	(14.8)	(15.0)	(45.0)	(40.7)
Other income, net	3.3	2.4	8.9	5.4
Income before income taxes	117.4	109.0	280.7	259.5
Income tax provision	(32.2)	(15.9)	(77.2)	(53.7)
Net income	$ 85.2	$ 93.1	$ 203.5	$ 205.8
Basic net income per share (in dollars per share)	$ 3.67	$ 3.85	$ 8.77	$ 8.34
Shares used in basic per share calculations (in shares)	23.2	24.2	23.2	24.7
Diluted net income per share (in dollars per share)	$ 3.64	$ 3.84	$ 8.72	$ 8.31
Shares used in diluted per share calculations (in shares)	23.4	24.3	23.3	24.8
Cash dividends paid per Class A and Class B share (in dollars per share)	$ 0.30	$ 0.29	$ 0.89	$ 0.85
New vehicle
Revenues:
Total revenues	$ 1,824.8	$ 1,733.0	$ 4,993.3	$ 4,914.5
Cost of sales:
Total cost of sales	1,724.8	1,632.1	4,711.9	4,625.2
Used vehicle retail
Revenues:
Total revenues	916.3	805.9	2,632.4	2,325.6
Cost of sales:
Total cost of sales	816.6	719.6	2,355.0	2,078.5
Used vehicle wholesale
Revenues:
Total revenues	74.4	92.0	233.5	253.2
Cost of sales:
Total cost of sales	73.3	90.6	229.7	249.0
Finance and insurance
Revenues:
Total revenues	136.3	121.1	382.7	342.1
Service, body and parts
Revenues:
Total revenues	340.5	311.3	993.3	908.4
Cost of sales:
Total cost of sales	169.0	156.9	492.2	461.9
Fleet and other
Revenues:
Total revenues	40.1	28.7	168.6	104.4
Cost of sales:
Total cost of sales	$ 37.8	$ 26.6	$ 159.8	$ 98.5