Variable Interest Entities - Carrying Amounts and Classification of Consolidated VIEs (Details) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents		$ 94.8	$ 69.2	$ 54.4	$ 40.5
Accounts receivable		498.7	459.9
Total current assets		755.8	662.1
Property and equipment, net		1,959.3	1,634.8
Operating lease right-of-use assets		276.5
Goodwill		2,305.2	2,100.8	$ 1,972.6	$ 1,927.2
Intangible assets, net		476.3	443.4
Deferred income tax assets		2.9	42.9
Other long-term assets		304.7	291.0
Total assets	[1]	6,080.7	5,175.0
Current liabilities:
Current portion of long-term debt		39.3	35.8
Current operating lease liabilities		40.4
Accounts payable		94.6	90.0
Other current liabilities		303.8	333.9
Total current liabilities		721.0	672.5
Long-term debt, net of current portion		3,023.3	2,478.6
Long-term operating lease liabilities		243.8
Total liabilities		4,148.0	3,356.3
Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure
Current assets:
Cash and cash equivalents		0.2	0.3
Accounts receivable		29.3	31.0
Other current assets		6.4	4.9
Total current assets		35.9	36.2
Property and equipment, net		122.6	111.5
Operating lease right-of-use assets		6.0
Goodwill		15.9	15.9
Intangible assets, net		3.3	4.3
Deferred income tax assets		0.7	0.6
Other long-term assets		30.6	29.0
Total assets		215.0	197.5
Current liabilities:
Current portion of long-term debt		0.8	0.6
Current operating lease liabilities		1.4
Accounts payable		6.7	5.2
Accrued payroll		7.7	7.0
Other current liabilities		9.3	38.0
Total current liabilities		25.9	50.8
Long-term debt, net of current portion		10.5	0.0
Long-term operating lease liabilities		4.7
Total liabilities		$ 41.1	$ 50.8

[1] Our consolidated assets as of December 31, 2019 and December 31, 2018 include total assets of variable interest entities of $215.0 million and $197.5 million, respectively, which cannot be used by us to settle the obligations of other entities. Our consolidated liabilities as of December 31, 2019 and December 31, 2018 include total liabilities of the variable interest entities of $41.1 million and $50.8 million, respectively. See Note 3, Variable Interest Entities.