Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2013
Income Tax Disclosure [Abstract]
Tax Reassessment Cash Liability	$ 15.6

Cash tax liability would be recognized had proposed adjustment were ultimately to be assessed.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration