Contract Assets and Liabilities - Additional Information1 (Detail) - Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date: 2019-10-01	Sep. 30, 2019
Minimum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation, revenue expected to be recognized	12 months
Maximum [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation, revenue expected to be recognized	24 months