Quarterly report pursuant to Section 13 or 15(d)

Income Taxes - Summary of Income Tax Expense and Effective Tax Rate (Detail)

v3.8.0.1
Income Taxes - Summary of Income Tax Expense and Effective Tax Rate (Detail) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Income Tax Disclosure [Abstract]        
Income tax expense $ 11,030 $ 24,376 $ 42,546 $ 67,144
Effective tax rate 9.40% 24.20% 12.90% 19.90%