Goodwill and Intangible Assets - Summary of Activity Related to Goodwill (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)
Goodwill, Gross [Roll Forward]
Goodwill, Gross Carrying Amount Beginning Balance	$ 265,388
Change in goodwill, Gross Carrying Amount	593
Goodwill, Gross Carrying Amount Ending Balance	265,981
Accumulated Impairment Losses [Roll Forward]
Goodwill, Accumulated Impairment Losses Beginning Balance	(304)
Change in goodwill, Accumulated Impairment Losses	0
Goodwill, Accumulated Impairment Losses Ending Balance	(304)
Goodwill [Roll Forward]
Goodwill, Net Carrying Amount Beginning Balance	265,084
Change in goodwill, Net Carrying Amount	593
Goodwill, Net Carrying Amount Ending Balance	$ 265,677