Condensed Consolidating Financial Information (Details 3) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed consolidating statement of cash flows
Net cash provided by continuing operating activities	$ 366.3	$ 301.0	$ 325.7
Investing activities:
Purchase of equipment and improvements	(174.8)	(174.7)	(150.9)
Proceeds from sale-leaseback transactions			1.6
Acquisitions, net	(355.0)	(314.0)	(233.3)
Other	(22.6)	(2.6)	8.8
Net cash used in continuing investing activities	(552.4)	(491.3)	(373.8)
Financing activities:
Repurchase of 7.75% senior subordinated notes			(390.8)us-gaap_RepaymentsOfSubordinatedDebt
Repurchase of 3.5% senior subordinated convertible notes			(62.7)us-gaap_RepaymentsOfConvertibleDebt
Net (repayments) borrowings of long-term debt	(71.3)	81.1	(51.7)
Net borrowings (repayments) of floor plan notes payable - non-trade	19.6	191.2	70.2
Payment of deferred financing fees	(4.4)us-gaap_PaymentsOfFinancingCosts		(8.6)us-gaap_PaymentsOfFinancingCosts
Repurchases of common stock	(15.5)	(15.8)	(9.8)
Dividends	(70.5)us-gaap_PaymentsOfDividendsCommonStock	(56.0)us-gaap_PaymentsOfDividendsCommonStock	(41.5)us-gaap_PaymentsOfDividendsCommonStock
Other	0.3	0.2	(1.1)
Net cash provided by continuing financing activities	158.2	200.7	54.0
Net cash provided by (used in) discontinued operations	15.2	(4.0)	11.2
Effect of exchange rate changes on cash and cash equivalents	(1.3)
Net change in cash and cash equivalents	(14.0)	6.4	17.1
Cash and cash equivalents, beginning of period	50.3	43.9	26.8
Cash and cash equivalents, end of period	36.3	50.3	43.9
Interest rate (as a percent)			3.50%
5.375% senior subordinated notes due 2024
Financing activities:
Issuance of senior subordinated notes	300.0
Interest rate (as a percent)	5.375%
5.75% senior subordinated notes due 2022
Financing activities:
Issuance of senior subordinated notes			550.0
Interest rate (as a percent)	5.75%	5.75%	5.75%
7.75% Notes
Financing activities:
Interest rate (as a percent)			7.75%
3.5% Notes
Financing activities:
Interest rate (as a percent)			3.50%
Penske Automotive Group \| 5.375% senior subordinated notes due 2024
Financing activities:
Interest rate (as a percent)	5.375%
Penske Automotive Group \| 5.75% senior subordinated notes due 2022
Financing activities:
Interest rate (as a percent)	5.75%	5.75%	5.75%
Reportable legal entities \| Penske Automotive Group
Condensed consolidating statement of cash flows
Net cash provided by continuing operating activities	(70.7)	46.5	45.5
Investing activities:
Purchase of equipment and improvements	(1.7)	(1.3)	(1.1)
Other	4.2	(17.5)	(3.3)
Net cash used in continuing investing activities	2.5	(18.8)	(4.4)
Financing activities:
Repurchase of 7.75% senior subordinated notes			(390.8)
Repurchase of 3.5% senior subordinated convertible notes			(62.7)
Net (repayments) borrowings of long-term debt	(100.0)	28.0	(98.9)
Net borrowings (repayments) of floor plan notes payable - non-trade	(41.4)	16.1	21.2
Payment of deferred financing fees	(4.4)		(8.6)
Repurchases of common stock	(15.5)	(15.8)	(9.8)
Dividends	(70.5)	(56.0)	(41.5)
Net cash provided by continuing financing activities	68.2	(27.7)	(41.1)
Reportable legal entities \| Penske Automotive Group \| 5.375% senior subordinated notes due 2024
Financing activities:
Issuance of senior subordinated notes	300.0
Reportable legal entities \| Penske Automotive Group \| 5.75% senior subordinated notes due 2022
Financing activities:
Issuance of senior subordinated notes			550.0
Reportable legal entities \| Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash provided by continuing operating activities	209.2	17.9	125.8
Investing activities:
Purchase of equipment and improvements	(101.2)	(116.7)	(100.4)
Acquisitions, net	(175.3)	(103.4)	(98.9)
Other		10.7	4.8
Net cash used in continuing investing activities	(276.5)	(209.4)	(194.5)
Financing activities:
Net (repayments) borrowings of long-term debt	9.0	2.7	27.7
Net borrowings (repayments) of floor plan notes payable - non-trade	35.9	181.1	41.0
Distributions from (to) parent	5.5	0.9	5.2
Net cash provided by continuing financing activities	50.4	184.7	73.9
Net cash provided by (used in) discontinued operations	3.8	(14.9)	3.8
Net change in cash and cash equivalents	(13.1)	(21.7)	9.0
Cash and cash equivalents, beginning of period	13.1	34.8	25.8
Cash and cash equivalents, end of period		13.1	34.8
Reportable legal entities \| Non-Guarantor Subsidiaries
Condensed consolidating statement of cash flows
Net cash provided by continuing operating activities	227.8	236.6	154.4
Investing activities:
Purchase of equipment and improvements	(71.9)	(56.7)	(49.4)
Proceeds from sale-leaseback transactions			1.6
Acquisitions, net	(179.7)	(210.6)	(134.4)
Other	(26.8)	4.2	7.3
Net cash used in continuing investing activities	(278.4)	(263.1)	(174.9)
Financing activities:
Net (repayments) borrowings of long-term debt	19.7	50.4	19.5
Net borrowings (repayments) of floor plan notes payable - non-trade	25.1	(6.0)	8.0
Other	0.3	0.2	(1.1)
Distributions from (to) parent	(5.5)	(0.9)	(5.2)
Net cash provided by continuing financing activities	39.6	43.7	21.2
Net cash provided by (used in) discontinued operations	11.4	10.9	7.4
Effect of exchange rate changes on cash and cash equivalents	(1.3)
Net change in cash and cash equivalents	(0.9)	28.1	8.1
Cash and cash equivalents, beginning of period	37.2	9.1	1.0
Cash and cash equivalents, end of period	$ 36.3	$ 37.2	$ 9.1

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