Income Taxes - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012
Income Taxes [Line Items]
Effective tax rate	(16.00%)	32.30%
Gross unrecognized tax benefits excluding interest and penalties	$ 41,134		$ 40,674
Net unrecognized tax benefit excluding interest and penalties that would impact effective tax rate	20,038
Accrued interest on unrecognized tax benefits	$ 1,771		$ 1,571
American Taxpayer Relief Act of 2012 [Member]
Income Taxes [Line Items]
Reduction in effective income tax rate	47.00%

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

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This element represents the total of accruals as of the date of the statement of financial position for interest recognized for an underpayment of income taxes computed by applying the applicable statutory rate of interest to the difference between a tax position recognized for financial reporting purposes and the amount previously taken or expected to be taken in a tax return of the entity and the amount of statutory penalties for a tax position claimed or expected to be claimed by the entity, in its tax return, that does not meet the minimum statutory threshold to avoid payment of penalties.

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