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Income Taxes - Additional information (Detail)
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Income Tax Disclosure [Abstract]    
Effective income tax rate 26.70%us-gaap_EffectiveIncomeTaxRateContinuingOperations 28.00%us-gaap_EffectiveIncomeTaxRateContinuingOperations