Other Comprehensive Income (Loss), Before Reclassification [Abstract]

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Reclassification from AOCI, Current Period [Abstract]

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount before tax and reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss) before reclassification adjustment from accumulated other comprehensive income (loss).

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Amount after tax of other comprehensive income (loss) attributable to parent entity.

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Amount before tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income (loss).

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Increase (Decrease) in AOCI
Beginning balance	$ 1,754.0	$ 1,215.9	$ 1,449.6	$ 1,255.7
Other comprehensive income (loss) before reclassifications:
Pre-tax			14.4	(75.6)
Tax effect			(4.9)	10.9
Amount reclassified from accumulated other comprehensive income (loss):
Benefit for income taxes			(2.6)	(1.7)
Net current period other comprehensive income (loss)	(10.2)	7.0	17.9	(59.3)
Ending balance	1,918.6	1,356.9	1,918.6	1,356.9
Interest Rate Swaps
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			3.1
Floorplan interest expense (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			5.0	5.3
Other interest expense, net (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			2.9	1.7
Realized loss on interest rate swap termination (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax				0.1
Accumulated other comprehensive income (loss)
Increase (Decrease) in AOCI
Beginning balance	(155.9)	(213.3)	(184.0)	(147.0)
Amount reclassified from accumulated other comprehensive income (loss):
Net current period other comprehensive income (loss)	(10.2)	7.0	17.9	(59.3)
Ending balance	(166.1)	(206.3)	(166.1)	(206.3)
Accumulated Income (Loss) On Foreign Currency Translation
Increase (Decrease) in AOCI
Beginning balance			(151.6)	(142.9)
Other comprehensive income (loss) before reclassifications:
Pre-tax			(6.7)	(24.4)
Tax effect			0.0	0.0
Amount reclassified from accumulated other comprehensive income (loss):
Benefit for income taxes			0.0	0.0
Net current period other comprehensive income (loss)			(6.7)	(24.4)
Ending balance	(158.2)	(167.2)	(158.2)	(167.2)
Accumulated Income (Loss) On Foreign Currency Translation \| Interest Rate Swaps
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			0.0
Accumulated Income (Loss) On Foreign Currency Translation \| Floorplan interest expense (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			0.0	0.0
Accumulated Income (Loss) On Foreign Currency Translation \| Other interest expense, net (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			0.0	0.0
Accumulated Income (Loss) On Foreign Currency Translation \| Realized loss on interest rate swap termination (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax				0.0
Accumulated Income (Loss) On Interest Rate Swaps
Increase (Decrease) in AOCI
Beginning balance			(32.5)	(4.1)
Other comprehensive income (loss) before reclassifications:
Pre-tax			21.0	(51.3)
Tax effect			(4.9)	10.9
Amount reclassified from accumulated other comprehensive income (loss):
Benefit for income taxes			(2.6)	(1.7)
Net current period other comprehensive income (loss)			24.5	(35.0)
Ending balance	$ (7.9)	$ (39.1)	(7.9)	(39.1)
Accumulated Income (Loss) On Interest Rate Swaps \| Interest Rate Swaps
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			3.1
Accumulated Income (Loss) On Interest Rate Swaps \| Floorplan interest expense (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			5.0	5.3
Accumulated Income (Loss) On Interest Rate Swaps \| Other interest expense, net (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax			$ 2.9	1.7
Accumulated Income (Loss) On Interest Rate Swaps \| Realized loss on interest rate swap termination (pre-tax)
Amount reclassified from accumulated other comprehensive income (loss):
Pre-tax				$ 0.1