Long-Term Debt (Details) £ in Millions, AUD in Millions, $ in Millions		1 Months Ended			12 Months Ended
	May. 01, 2015 USD ($)	Apr. 30, 2015 GBP (£)	Nov. 30, 2014 USD ($)	Aug. 31, 2012 USD ($)	Dec. 31, 2015 GBP (£)	Dec. 31, 2015 AUD	Dec. 31, 2015 GBP (£)	Dec. 31, 2015 USD ($)	Mar. 31, 2015 GBP (£)	Dec. 31, 2014 USD ($)	Dec. 31, 2013	Dec. 31, 2012 GBP (£)
Long Term Debt
Total long-term debt								$ 1,284.3		$ 1,353.2
Less: current portion								(29.2)		(37.2)
Net long-term debt								1,255.1		1,316.0
Scheduled maturities of long-term debt for each of the next five years and thereafter
2016								29.2
2017								18.0
2018								168.5
2019								22.2
2020								82.1
2021 and thereafter								964.3
Total long-term debt								1,284.3		1,353.2
Letters of credit outstanding								24.1
U.S. Credit Agreement Revolving Credit Line
Long Term Debt
Total long-term debt								160.0
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt								160.0
Initial borrowing capacity	$ 450.0
Maximum credit available	700.0
Balance outstanding under credit agreement								160.0
Revolving loans solely for future U.S. acquisitions	$ 250.0
U.S. Credit Agreement Revolving Credit Line | LIBOR portion
Scheduled maturities of long-term debt for each of the next five years and thereafter
Base rate of interest on loans	LIBOR
Line of credit basis spread on variable rate (as a percent)	2.00%
Incremental interest rate for uncollateralized borrowings in excess of maximum limit (as a percent)	1.50%
U.S. Credit Agreement Term Loan
Long Term Debt
Total long-term debt								0.0		88.0
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt								0.0		88.0
U.K. Credit Agreement Revolving Credit Line
Long Term Debt
Total long-term debt								70.7		121.5
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt								70.7		121.5
Maximum credit available | £		£ 150.0							£ 100.0
Balance outstanding under credit agreement							£ 48.0	70.7
U.K. Credit Agreement Revolving Credit Line | LIBOR portion
Scheduled maturities of long-term debt for each of the next five years and thereafter
Base rate of interest on loans		LIBOR
U.K. Credit Agreement Revolving Credit Line | Minimum | LIBOR portion
Scheduled maturities of long-term debt for each of the next five years and thereafter
Line of credit basis spread on variable rate (as a percent)		1.35%
U.K. Credit Agreement Revolving Credit Line | Maximum | LIBOR portion
Scheduled maturities of long-term debt for each of the next five years and thereafter
Line of credit basis spread on variable rate (as a percent)		3.00%
U.K. Agreement Term Loan
Long Term Debt
Total long-term debt										18.7
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt										18.7
Maximum credit available | £												£ 30.0
Repayment of term loan, quarterly installments | £					£ 1.5
Frequency of principal repayments					Quarterly
Final payment due December 31, 2015 | £							£ 7.5
U.K. Agreement Term Loan | Minimum
Scheduled maturities of long-term debt for each of the next five years and thereafter
Low end of interest rate, depending on UK subsidiaries ratios (as a percent)					2.675%
U.K. Agreement Term Loan | Maximum
Scheduled maturities of long-term debt for each of the next five years and thereafter
High end of interest rate, depending on UK subsidiaries ratios (as a percent)					4.325%
U.K. Credit Agreement Overdraft Line of Credit
Long Term Debt
Total long-term debt										5.7
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt										5.7
U.K. Credit Agreement Overdraft Line of Credit | Bank of England Base Rate
Scheduled maturities of long-term debt for each of the next five years and thereafter
Base rate of interest on loans		Bank of England Base Rate
Line of credit basis spread on variable rate (as a percent)		1.75%
5.375% Senior Subordinated Notes Due 2024
Long Term Debt
Total long-term debt								$ 300.0		$ 300.0
Interest rate (as a percent)						5.375%	5.375%	5.375%		5.375%
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt								$ 300.0		$ 300.0
Debt issued			$ 300.0
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)						100.00%	100.00%	100.00%
5.375% Senior Subordinated Notes Due 2024 | Debt redemption prior to December 1, 2017
Scheduled maturities of long-term debt for each of the next five years and thereafter
Change of control, redemption price as a percentage of principal			101.00%
Sale of assets, redemption price as percentage of principal			100.00%
5.375% Senior Subordinated Notes Due 2024 | Penske Automotive Group
Long Term Debt
Interest rate (as a percent)						5.375%	5.375%	5.375%		5.375%
5.375% Senior Subordinated Notes Due 2024 | Maximum | Debt redemption prior to December 1, 2017
Scheduled maturities of long-term debt for each of the next five years and thereafter
Specified equity offerings, percentage of debt which may be redeemed			40.00%
5.75% Senior Subordinated Notes Due 2022
Long Term Debt
Total long-term debt								$ 550.0		$ 550.0
Interest rate (as a percent)						5.75%	5.75%	5.75%		5.75%
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt								$ 550.0		$ 550.0
Debt issued				$ 550.0
Domestic Subsidiaries ownership guaranteeing obligations (as a percent)						100.00%	100.00%	100.00%
5.75% Senior Subordinated Notes Due 2022 | Debt Redemption Prior To October 1, 2017
Scheduled maturities of long-term debt for each of the next five years and thereafter
Change of control, redemption price as a percentage of principal				101.00%
Sale of assets, redemption price as percentage of principal				100.00%
5.75% Senior Subordinated Notes Due 2022 | Penske Automotive Group
Long Term Debt
Interest rate (as a percent)						5.75%	5.75%	5.75%		5.75%	5.75%
U.S. Commercial Truck Capital Loan
Long Term Debt
Total long-term debt										$ 60.5
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt										60.5
Balance outstanding under credit agreement										60.5
Australia Working Capital Loan Agreement
Long Term Debt
Total long-term debt								$ 5.5
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt								5.5
Maximum credit available						AUD 28.0		20.4
Base rate of interest on loans					30-day Bill Rate
Line of credit basis spread on variable rate (as a percent)					2.35%
Balance outstanding under credit agreement								5.5
Mortgage Facilities
Long Term Debt
Total long-term debt								165.8		169.7
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt								165.8		169.7
Balance outstanding under credit agreement								165.8
Other Debt Securities
Long Term Debt
Total long-term debt								32.3		39.1
Scheduled maturities of long-term debt for each of the next five years and thereafter
Total long-term debt								$ 32.3		$ 39.1