Inventories - Narrative (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Inventory Net [Abstract]
LIFO expense (benefit)	$ 1.6	$ (0.1)	$ (4.3)

The difference between the change in the inventory reserve representing the cumulative difference in cost between the first in, first out and the last in, first out inventory valuation methods and any LIFO decrement which have been reflected in the statement of income during the period.

No definition available.

Name:	us-gaap_InventoryLIFOReserveEffectOnIncomeNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration