Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill, relates to acquisition			$ 3,500,000		$ 3,500,000
Impairment losses			0
Amortization expense	$ 500,000	$ 600,000	$ 1,500,000	$ 1,700,000