Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization expense	$ 2,400	$ 2,100	$ 7,139	$ 6,384
Estimated amortization expense, remainder of 2017	2,300		2,300
Estimated amortization expense, year 2018	9,400		9,400
Estimated amortization expense, year 2019	9,400		9,400
Estimated amortization expense, year 2020	9,400		9,400
Estimated amortization expense, year 2021	9,400		9,400
Estimated amortization expense, Thereafter	$ 66,600		$ 66,600