Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Reclassification adjustment on derivatives included in net income, tax	$ 0.4	$ 0.4

Amount of tax expense (benefit) of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 220

-SubTopic 10

-Section 45

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=28358780&loc=d3e640-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4

-Subparagraph c

-URI http://asc.fasb.org/extlink&oid=7476318&loc=d3e41638-113959

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration