Commitments and Contingencies - Estimated Future Cash Outlays Related to Principal Contractual Obligations (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Recorded Unconditional Purchase Obligation [Line Items]
2013	$ 172.8
2014	71.0
2015	31.9
2016	15.3
2017	10.8
Thereafter	12.0
Total	$ 313.8

Amount of the recorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25383-109308

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 10

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 6

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

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Amount of the recorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year.

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Amount of the recorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year.

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Amount of the recorded unconditional purchase obligation maturing in the fourth fiscal year following the latest fiscal year.

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Amount of the recorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year.

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Amount of the recorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year.

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Amount of the recorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year.

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