Income Taxes - Additional Information (Detail)
 3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Income Tax Disclosure [Abstract]        
Effective tax rate (as a percent) 34.10% 34.90% 33.80% 34.40%