Goodwill - Additional Information (Detail) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Goodwill Disclosure [Abstract]
Goodwill	$ 255,359,000		$ 186,483,000
Goodwill, Period Increase (Decrease)	68,916,000
Goodwill, Acquired During Period	70,500,000
Goodwill, Translation and Purchase Accounting Adjustments	1,600,000
Impairment charges on goodwill	$ 0	$ 0