Goodwill and Intangible Assets - Summary of Amortization Expense Relating to Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Amortization expense	$ 8,317	$ 8,732	$ 17,566	$ 17,226