Income Taxes - Summary of Information Related to Interest and Penalties on Uncertain Tax Positions (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Interest expense	$ 0.1	$ 0.3
Accrued interest payable	$ 0.7		$ 0.6

The amount of estimated interest recognized in the period arising from income tax examinations.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32718-109319

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