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Income Taxes - Additional Information (Detail) - USD ($)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Dec. 31, 2016
Income Tax Disclosure [Abstract]          
Effective income tax rate (as a percent) 25.40% 28.80% 26.30% 30.20%  
Liability for uncertain tax positions $ 8.4   $ 8.4   $ 8.4
Unrecognized tax benefits if recognized that would affect effective tax rate 4.2   4.2   4.2
Accrued interest related to uncertain tax positions 1.0   1.0   0.8
Accrued penalties related to uncertain tax positions 0.3   0.3   $ 0.3
Unrecognized tax benefits subject to change within the next 12 months $ 4.0   $ 4.0