Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment loss			$ 0
Amortization expense	$ 2,400,000	$ 1,100,000	$ 6,100,000	$ 3,200,000