Financial Instruments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
Sep. 30, 2010 Swap	Dec. 31, 2012
Derivatives, Fair Value [Line Items]
Number of interest rate swap agreements	2
Derivative gains included in AOCI		$ 1.2
Cross Currency Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative instrument maturity period (years)		10 years
Forward Currency Contracts [Member]
Derivatives, Fair Value [Line Items]
Number of multiple forward currency contracts matured		4

The number of forward currency contracts that matured during the period.

No definition available.

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- Definition

The number of interest rate swaps entered into during the period.

+ References

No definition available.

+ Details

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- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(2)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

+ Details

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- Definition

Maximum length of time over which the entity is hedging its exposure to the variability in future cash flows for forecasted transactions, excluding those forecasted transactions related to the payment of variable interest on existing financial instruments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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