Revenue - Unsatisfied Performance Obligation - Additional Information (Detail)	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-01-01
Revenue From Contract With Customer [Line Items]
Unsatisfied performance obligations, expected to recognize	66.00%
Unsatisfied performance obligations, expected to recognize, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2020-01-01
Revenue From Contract With Customer [Line Items]
Unsatisfied performance obligations, expected to recognize	26.00%
Unsatisfied performance obligations, expected to recognize, period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2021-01-01
Revenue From Contract With Customer [Line Items]
Unsatisfied performance obligations, expected to recognize	8.00%
Unsatisfied performance obligations, expected to recognize, period