Debt and Interest Expense - Summary of Total Long-term Debt (Detail) - USD ($) $ in Millions		Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Total Borrowings		$ 1,782.0	$ 997.5
Unamortized deferred financing costs and discounts		(28.5)	(16.4)
Total debt		1,753.5	981.1
Less: current maturities of long-term debt	[1]		11.3
Total long-term debt		1,753.5	969.8	[1]
Term Loan A Facility
Debt Instrument [Line Items]
Total Borrowings		400.0	197.5
Revolving Credit Facility
Debt Instrument [Line Items]
Total Borrowings		32.0
Fixed-Rate Senior Notes
Debt Instrument [Line Items]
Total Borrowings		1,350.0	800.0
Fixed-Rate Senior Notes | 5.625% Fixed Rate Senior Notes due 2026
Debt Instrument [Line Items]
Total Borrowings		800.0	$ 800.0
Fixed-Rate Senior Notes | 5.125% Fixed Rate Senior Notes due 2028
Debt Instrument [Line Items]
Total Borrowings		$ 550.0

[1] The financial information presented in this report has been retrospectively adjusted for the acquisition of Hess Infrastructure Partners LP.