Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense	$ 900,000	$ 800,000	$ 800,000
Subsequent impairment of the underlying assets	0
Expected annual amortization expense for 2016	900,000
Expected annual amortization expense for 2017	900,000
Expected annual amortization expense for 2018	900,000
Expected annual amortization expense for 2019	900,000
Expected annual amortization expense for 2020	$ 200,000