Condensed Consolidating Financial Information - Balance Sheet (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Condensed consolidating balance sheet
Cash and cash equivalents	$ 20.7	$ 24.0	$ 97.5	$ 62.4
Accounts receivable, net	827.7	879.0
Inventories	3,711.9	3,408.2
Other current assets	104.2	73.9
Assets held for sale		8.4
Total current assets	4,664.5	4,393.5
Property and equipment, net	1,990.3	1,806.5
Intangible assets	2,109.0	1,711.3
Equity method investments	921.5	893.4
Other long-term assets	26.6	28.3
Total assets	9,711.9	8,833.0
Floor plan notes payable	2,151.1	2,084.5
Floor plan notes payable - non-trade	1,364.7	1,233.3
Accounts payable	559.9	497.4
Accrued expenses	413.2	360.0
Current portion of long-term debt	70.1	48.3
Liabilities held for sale	0.7	6.1
Total current liabilities	4,559.7	4,229.6
Long-term debt	1,955.8	1,828.8
Deferred tax liabilities	655.2	564.6
Other long-term liabilities	524.5	430.5
Total liabilities	7,695.2	7,053.5
Total equity	2,016.7	1,779.5
Total liabilities and equity	$ 9,711.9	$ 8,833.0
5.75% senior subordinated notes due 2022
Condensed consolidating balance sheet
Interest rate (as a percent)	5.75%	5.75%
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)	100.00%
5.375% Senior Subordinated Notes Due 2024
Condensed consolidating balance sheet
Interest rate (as a percent)	5.375%	5.375%
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)	100.00%
5.50% senior subordinated notes due 2026
Condensed consolidating balance sheet
Interest rate (as a percent)	5.50%	5.50%
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)	100.00%
Eliminations
Condensed consolidating balance sheet
Accounts receivable, net	$ (456.0)	$ (447.0)
Total current assets	(456.0)	(447.0)
Other long-term assets	(2,542.0)	(2,215.0)
Total assets	(2,998.0)	(2,662.0)
Accrued expenses	(456.0)	(447.0)
Total current liabilities	(456.0)	(447.0)
Long-term debt	(177.3)	(175.8)
Total liabilities	(633.3)	(622.8)
Total equity	(2,364.7)	(2,039.2)
Total liabilities and equity	(2,998.0)	(2,662.0)
Reportable legal entities | Penske Automotive Group
Condensed consolidating balance sheet
Accounts receivable, net	456.0	447.0
Other current assets	7.5	14.3
Total current assets	463.5	461.3
Property and equipment, net	3.8	3.3
Equity method investments	856.6	833.7
Other long-term assets	2,547.5	2,220.6
Total assets	3,871.4	3,518.9
Floor plan notes payable - non-trade	185.6	156.0
Accounts payable	6.5	4.9
Accrued expenses	1.1	0.9
Total current liabilities	193.2	161.8
Long-term debt	1,661.5	1,577.6
Total liabilities	1,854.7	1,739.4
Total equity	2,016.7	1,779.5
Total liabilities and equity	3,871.4	3,518.9
Reportable legal entities | Guarantor Subsidiaries
Condensed consolidating balance sheet
Cash and cash equivalents	1.9	9.4	11.2
Accounts receivable, net	392.1	483.6
Inventories	1,944.9	1,830.5
Other current assets	19.2	14.6
Assets held for sale		8.4
Total current assets	2,358.1	2,346.5
Property and equipment, net	984.0	961.0
Intangible assets	1,334.8	1,079.6
Other long-term assets	4.3	4.1
Total assets	4,681.2	4,391.2
Floor plan notes payable	1,126.0	1,178.0
Floor plan notes payable - non-trade	678.9	623.2
Accounts payable	159.8	171.9
Accrued expenses	95.7	77.2
Current portion of long-term debt	10.0	6.0
Liabilities held for sale	0.7	6.1
Total current liabilities	2,071.1	2,062.4
Long-term debt	192.7	186.0
Deferred tax liabilities	649.4	560.9
Other long-term liabilities	61.7	65.2
Total liabilities	2,974.9	2,874.5
Total equity	1,706.3	1,516.7
Total liabilities and equity	4,681.2	4,391.2
Reportable legal entities | Non-Guarantor Subsidiaries
Condensed consolidating balance sheet
Cash and cash equivalents	18.8	14.6	$ 86.3	$ 62.4
Accounts receivable, net	435.6	395.4
Inventories	1,767.0	1,577.7
Other current assets	77.5	45.0
Total current assets	2,298.9	2,032.7
Property and equipment, net	1,002.5	842.2
Intangible assets	774.2	631.7
Equity method investments	64.9	59.7
Other long-term assets	16.8	18.6
Total assets	4,157.3	3,584.9
Floor plan notes payable	1,025.1	906.5
Floor plan notes payable - non-trade	500.2	454.1
Accounts payable	393.6	320.6
Accrued expenses	772.4	728.9
Current portion of long-term debt	60.1	42.3
Total current liabilities	2,751.4	2,452.4
Long-term debt	278.9	241.0
Deferred tax liabilities	5.8	3.7
Other long-term liabilities	462.8	365.3
Total liabilities	3,498.9	3,062.4
Total equity	658.4	522.5
Total liabilities and equity	$ 4,157.3	$ 3,584.9