Goodwill and Other Intangible Assets, Net - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment charges	$ 3,900.0
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Expense (income) adjustment for amortization			$ 13.6
Continuing Operations [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense for intangible assets		$ 187.0	195.0	$ 123.0
Continuing Operations [Member] | Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Expense (income) adjustment for amortization			16.4
Discontinued Operations [Member]
Finite-Lived Intangible Assets [Line Items]
Amortization expense for intangible assets		$ 44.6	$ 156.0	$ 99.8