Segment Information - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) Segment	Mar. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | Segment	2
Intersegments sales	$ 541,296	$ 450,977
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegments sales	(4,489)	(3,233)
Intersegment Eliminations [Member] | Clinical to Commercial [Member]
Segment Reporting Information [Line Items]
Intersegments sales	100	600
Intersegment Eliminations [Member] | Commercial To Clinical Or Corporate And Other Segment [Member]
Segment Reporting Information [Line Items]
Intersegments sales	$ 4,400	$ 2,600