Employee Benefits Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Pension and Other Postretirement Benefit Contributions [Abstract]
Contribution to pension plans	$ 2.7us-gaap_PensionContributions	$ 4.2us-gaap_PensionContributions

The amount of cash or cash equivalents contributed by the entity to fund its pension plans.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-Subparagraph (g)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3536-108585

Name:	us-gaap_PensionContributions
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration