Business and Geographic Segments - Business Segment Information (Parenthetical) (Detail) (USD $)	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Write-down and loss on disposal of assets held for sale	$ 1,200,000	$ 405,000	$ 1,100,000	$ 1,100,000	$ 500,000

The loss recognized for any initial write-down from carrying value to fair value less cost to sell for a classified as held for sale.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 144

-Paragraph 33, 47

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6360339&loc=d3e1361-107760

Name:	us-gaap_LongLivedAssetsHeldForSaleImpairmentCharge
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant