Commitment and Contingencies - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2013
Commitments And Contingencies Disclosure [Abstract]
Potential loss range minimum	$ 0
Potential loss range maximum	27.7
Total awarded value for damages to plaintiffs	$ 27.7

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Amount of damages awarded to the plaintiff in the legal matter.

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-Name Accounting Standards Codification

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-SubTopic 20

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The estimated maximum amount of possible loss from the contingency.

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-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

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-Subparagraph (b)

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The estimated minimum amount of possible loss from the contingency.

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