Inventories - Additional Information (Detail)	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Percentage of inventories valued on the LIFO method	33.00%	42.00%

The percentage of LIFO (last in first out) inventory to total inventory as of the balance sheet date if other than 100 percent.

No definition available.

Name:	us-gaap_PercentageOfLIFOInventory
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant