Goodwill and Other Intangible Assets - Components of Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill	$ 383,861	$ 371,773	$ 371,561	$ 385,292
Other intangible assets (net of accumulated amortization)	210	1,821
Goodwill and other intangible assets, Total	$ 384,071	$ 373,594