Property and Equipment - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2017 USD ($)
Property, Plant and Equipment [Abstract]
Property tax abatement, period	8 years
Amounts in Industrial revenue bond exchanged for property tax abatement	$ 650,000,000
Cash exchanged for property tax abatement	$ 0
Industrial revenue bonds maturity period	9 years