Related Party Transactions - Summary of Related Party Expenses (Detail) - USD ($) $ in Thousands, shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Related Party Transaction [Line Items]
Total related party expenses	$ 0	$ 353	$ 623	$ 892
Distributions-in-kind of common stock (in shares)	6.3
Pharmacovigilance services | INC Research Holdings, Inc.
Related Party Transaction [Line Items]
Total related party expenses	$ 0	293	0	647
Avista | Offering costs paid on behalf of Avista pursuant to registration rights agreement
Related Party Transaction [Line Items]
Total related party expenses	0	0	326	0
VWR Scientific | Inventory supplies
Related Party Transaction [Line Items]
Total related party expenses	$ 0	$ 60	$ 297	$ 245