v2.4.0.6
Income Taxes - Total Income Tax Expense Differed from Amounts Computed by Applying U.S. Federal Statutory Tax Rates to Pre-Tax Income (Parenthetical) (Detail)
12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Reconciliation Of Effective Income Tax Rate [Line Items]      
Statutory tax rate 34.00% 34.00% 34.00%