Other Operating Expense (Income), Net - Additional Information (Detail) - USD ($)	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Component Of Other Income And Expense [Line Items]
Nonrecurring repair costs	$ 12,425,000
Other Operating Income, Net
Component Of Other Income And Expense [Line Items]
Gain on sale of real estate		$ 13,500,000
Other Operating Income, Net | Chief Financial Officer
Component Of Other Income And Expense [Line Items]
Retirement related expense including both cash and stock-based compensation		$ 7,500,000