Goodwill and Other Intangible Assets, Net (Finite-lived Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-lived Intangible Assets
Gross Intangible Assets, Beginning Balance	$ 837.3	$ 793.7
Gross Intangible Assets, Acquisitions	60.7	48.8
Gross Intangible Assets, Divestitures	(1.0)	(5.2)
Gross Intangible Assets, Ending Balance	897.0	837.3
Accumulated Amortization, Beginning Balance	(703.4)	(687.2)
Accumulated Amortization, Additions Charged to Expense	(21.1)	(20.6)
Accumulated Amortization, Divestitures	0.6	4.4
Accumulated Amortization, Ending Balance	(723.9)	(703.4)
Other Intangible Assets, Net as of December 31, 2020	173.1	133.9
Customer relationships
Finite-lived Intangible Assets
Gross Intangible Assets, Beginning Balance	733.8	692.4
Gross Intangible Assets, Acquisitions	54.4	41.4
Gross Intangible Assets, Divestitures	(0.1)	0.0
Gross Intangible Assets, Ending Balance	788.1	733.8
Accumulated Amortization, Beginning Balance	(623.0)	(607.2)
Accumulated Amortization, Additions Charged to Expense	(16.6)	(16.0)
Accumulated Amortization, Divestitures	0.1	0.2
Accumulated Amortization, Ending Balance	(639.5)	(623.0)
Other Intangible Assets, Net as of December 31, 2020	148.6	110.8
Non-compete agreements
Finite-lived Intangible Assets
Gross Intangible Assets, Beginning Balance	45.3	37.0
Gross Intangible Assets, Acquisitions	6.3	7.4
Gross Intangible Assets, Divestitures	(0.2)	0.9
Gross Intangible Assets, Ending Balance	51.4	45.3
Accumulated Amortization, Beginning Balance	(35.3)	(31.5)
Accumulated Amortization, Additions Charged to Expense	(3.9)	(3.8)
Accumulated Amortization, Divestitures	0.1	0.0
Accumulated Amortization, Ending Balance	(39.1)	(35.3)
Other Intangible Assets, Net as of December 31, 2020	12.3	10.0
Other intangible assets
Finite-lived Intangible Assets
Gross Intangible Assets, Beginning Balance	58.2	64.3
Gross Intangible Assets, Acquisitions	0.0	0.0
Gross Intangible Assets, Divestitures	(0.7)	(6.1)
Gross Intangible Assets, Ending Balance	57.5	58.2
Accumulated Amortization, Beginning Balance	(45.1)	(48.5)
Accumulated Amortization, Additions Charged to Expense	(0.6)	(0.8)
Accumulated Amortization, Divestitures	0.4	4.2
Accumulated Amortization, Ending Balance	(45.3)	(45.1)
Other Intangible Assets, Net as of December 31, 2020	$ 12.2	$ 13.1