Revenue Recognition - Additional Information (Detail1) - USD ($) $ in Millions	Oct. 01, 2018	Sep. 30, 2018
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation	$ 425.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2018-10-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation		$ 29.6
Revenue, remaining performance obligation, expected timing of satisfaction, period		3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation		$ 98.1
Revenue, remaining performance obligation, expected timing of satisfaction, period		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation		$ 71.5
Revenue, remaining performance obligation, expected timing of satisfaction, period		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation		$ 48.9
Revenue, remaining performance obligation, expected timing of satisfaction, period		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2022-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation		$ 42.1
Revenue, remaining performance obligation, expected timing of satisfaction, period		1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2023-01-01
Disaggregation Of Revenue [Line Items]
Revenue, remaining performance obligation		$ 137.4
Revenue, remaining performance obligation, expected timing of satisfaction, period		1 year