Commitment and Contingencies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies [Line Items]
Product liability insurance for individual losses in excess of accrual amount	$ 125,000,000	$ 125,000,000
Amounts in excess to be covered by third party insurance	$ 7,500,000	$ 7,500,000