Quarterly Financial Results (Unaudited) - Summarized Quarterly Data (Parenthetical) (Detail) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Impairment charge of intangible assets	$ 3.4
Decrease in diluted earnings per share	$ 0.09

The amount of impairment loss recognized in the period resulting from the write-down of the carrying amount of a finite-lived intangible asset to fair value.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 3

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16373-109275

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