Goodwill and Other Intangible Assets - Components of Goodwill and Other Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 327,050	$ 320,761	$ 324,963	$ 335,402
Other intangible assets (net of accumulated amortization)	5,571	6,215
Goodwill and other intangible assets, Total	$ 332,621	$ 326,976