Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Accounting Policies [Abstract]
Cash equivalents original maturity period	Three months or less
Percentage of inventories valued using the last-in, first-out (LIFO)	43.00%us-gaap_PercentageOfLIFOInventory	45.00%us-gaap_PercentageOfLIFOInventory

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