Long-Term Investments - Additional Information (Detail) (USD $)	3 Months Ended
Mar. 31, 2013
Investment [Line Items]
Eligibility to receive a royalty fee	1.00%
Royalty income, nonoperating	$ 0
Carrying value of investment	$ 0
Maximum
Investment [Line Items]
Ownership percentage under Cost Method for Investments	3.00%

This element represents the aggregate carrying amount of all cost-method investments held by the Company. Generally, such investments do not have readily determinable fair values and are not required to be accounted for by the equity method. The carrying amount of such securities equates to cost, adjusted for other-than-temporary impairment. The cost method and lower-of-cost or market, an adaptation of the cost method, is generally followed for most investments in noncontrolled corporations, in some corporate joint ventures, and to a lesser extent in unconsolidated subsidiaries, particularly foreign.

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

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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