Condensed Consolidating Financial Information - Balance Sheet (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014	Nov. 30, 2014	Aug. 31, 2012
Condensed consolidating balance sheet
Cash and cash equivalents	$ 45.6	$ 62.4	$ 66.8	$ 36.3
Accounts receivable, net	835.6	782.3
Inventories	3,513.4	3,463.5
Other current assets	101.5	85.6
Assets held for sale	9.8	13.1
Total current assets	4,505.9	4,406.9
Property and equipment, net	1,545.8	1,520.1
Intangible assets	1,734.8	1,730.8
Equity method investments	366.6	336.4
Other long-term assets	19.8	19.2
Total assets	8,172.9	8,013.4
Floor plan notes payable	2,262.5	2,247.2
Floor plan notes payable - non-trade	1,187.3	1,132.4
Accounts payable	541.5	493.8
Accrued expenses	388.0	378.1
Current portion of long-term debt	54.5	28.0
Liabilities held for sale	5.1	6.2
Total current liabilities	4,438.9	4,285.7
Long-term debt	1,330.1	1,247.0
Deferred tax liabilities	437.8	433.4
Other long-term liabilities	242.1	212.4
Total liabilities	6,448.9	6,178.5
Total equity	1,724.0	1,834.9
Total liabilities and equity	$ 8,172.9	$ 8,013.4
5.75% senior subordinated notes due 2022
Condensed consolidating balance sheet
Interest rate (as a percent)	5.75%	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%			5.375%
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)	100.00%
Penske Automotive Group
Condensed consolidating balance sheet
Accounts receivable, net	$ 434.6	$ 430.4
Other current assets	4.2	3.9
Total current assets	438.8	434.3
Property and equipment, net	4.0	4.0
Equity method investments	303.6	298.2
Other long-term assets	2,215.4	2,259.9
Total assets	2,961.8	2,996.4
Floor plan notes payable - non-trade	155.0	154.7
Accounts payable	2.4	4.8
Accrued expenses	1.1	0.1
Total current liabilities	158.5	159.6
Long-term debt	1,079.3	1,001.9
Total liabilities	1,237.8	1,161.5
Total equity	1,724.0	1,834.9
Total liabilities and equity	2,961.8	2,996.4
Guarantor Subsidiaries
Condensed consolidating balance sheet
Accounts receivable, net	323.1	400.8
Inventories	1,685.3	1,650.5
Other current assets	29.7	28.3
Assets held for sale	9.7	8.9
Total current assets	2,047.8	2,088.5
Property and equipment, net	837.3	822.0
Intangible assets	878.5	878.5
Other long-term assets	7.6	7.2
Total assets	3,771.2	3,796.2
Floor plan notes payable	1,267.7	1,295.0
Floor plan notes payable - non-trade	368.3	339.8
Accounts payable	140.4	143.3
Accrued expenses	144.7	112.3
Current portion of long-term debt	4.1	5.7
Liabilities held for sale	4.9	4.4
Total current liabilities	1,930.1	1,900.5
Long-term debt	132.0	109.2
Deferred tax liabilities	421.3	413.4
Other long-term liabilities	68.3	68.9
Total liabilities	2,551.7	2,492.0
Total equity	1,219.5	1,304.2
Total liabilities and equity	3,771.2	3,796.2
Non-Guarantor Subsidiaries
Condensed consolidating balance sheet
Cash and cash equivalents	45.6	62.4	$ 66.8	$ 36.3
Accounts receivable, net	512.5	381.5
Inventories	1,828.1	1,813.0
Other current assets	67.6	53.4
Assets held for sale	0.1	4.2
Total current assets	2,453.9	2,314.5
Property and equipment, net	704.5	694.1
Intangible assets	856.3	852.3
Equity method investments	63.0	38.2
Other long-term assets	5.9	5.5
Total assets	4,083.6	3,904.6
Floor plan notes payable	994.8	952.2
Floor plan notes payable - non-trade	664.0	637.9
Accounts payable	398.7	345.7
Accrued expenses	676.8	696.1
Current portion of long-term debt	50.4	22.3
Liabilities held for sale	0.2	1.8
Total current liabilities	2,784.9	2,656.0
Long-term debt	374.4	392.3
Deferred tax liabilities	16.5	20.0
Other long-term liabilities	173.8	143.5
Total liabilities	3,349.6	3,211.8
Total equity	734.0	692.8
Total liabilities and equity	4,083.6	3,904.6
Eliminations
Condensed consolidating balance sheet
Accounts receivable, net	(434.6)	(430.4)
Total current assets	(434.6)	(430.4)
Other long-term assets	(2,209.1)	(2,253.4)
Total assets	(2,643.7)	(2,683.8)
Accrued expenses	(434.6)	(430.4)
Total current liabilities	(434.6)	(430.4)
Long-term debt	(255.6)	(256.4)
Total liabilities	(690.2)	(686.8)
Total equity	(1,953.5)	(1,997.0)
Total liabilities and equity	$ (2,643.7)	$ (2,683.8)