Goodwill and Other Intangible Assets - Components of Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	$ 373,117	$ 320,761	$ 335,402	$ 345,453
Other intangible assets (net of accumulated amortization)	8,907	6,215
Goodwill and other intangible assets, Total	$ 382,024	$ 326,976