Annual report pursuant to Section 13 and 15(d)

Provision for Federal and Foreign Income Tax Expense for Continuing Operations (Detail)

v3.8.0.1
Provision for Federal and Foreign Income Tax Expense for Continuing Operations (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Income Tax Disclosure [Abstract]      
Income before income taxes, U.S. $ 280,535 $ 274,756 $ 259,652
Income before income taxes, Foreign 64,842 85,890 88,015
Income before income taxes $ 345,377 $ 360,646 $ 347,667