Derivatives - Summary of Various Interest Rate Hedges (Detail) - Incremental Term Loan Facility [Member] - Interest Rate Hedge [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Derivative [Line Items]
Fair Value Asset (Liability)	$ (14.0)	$ (5.7)
Swap Agreement One [Member]
Derivative [Line Items]
Trade Date	Sep. 29, 2016
Effective Date	Sep. 30, 2016
Maturity	Sep. 30, 2020
Fixed Rate	1.198%
Notional Amount at Effective Date	$ 335.0
Fair Value Asset (Liability)		0.8
Swap Agreement Two [Member]
Derivative [Line Items]
Trade Date	Apr. 03, 2019
Effective Date	Apr. 05, 2019
Maturity	Mar. 31, 2023
Fixed Rate	2.309%
Notional Amount at Effective Date	$ 300.0
Fair Value Asset (Liability)	$ (12.4)	$ (6.5)
Swap Agreement Three [Member]
Derivative [Line Items]
Trade Date	Oct. 29, 2020
Effective Date	Oct. 26, 2021
Maturity	Feb. 28, 2025
Fixed Rate	0.485%
Notional Amount at Effective Date	$ 200.0
Fair Value Asset (Liability)	$ (0.7)
Swap Agreement Four [Member]
Derivative [Line Items]
Trade Date	Oct. 29, 2020
Effective Date	Mar. 31, 2022
Maturity	Feb. 28, 2025
Fixed Rate	0.623%
Notional Amount at Effective Date	$ 100.0
Fair Value Asset (Liability)	$ (0.9)