Goodwill and Other Intangible Assets - Roll Forward of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Balance at beginning of year	$ 175,820	$ 175,820
Additions	115,944	0
Balance at End of Year	$ 291,764	$ 175,820