Financial Statement Details - Schedule of Goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Goodwill [Roll Forward]
Gross goodwill, beginning balance	$ 568,668
Accumulated impairment losses	(16,166)
Goodwill net of accumulated impairment losses	552,502
Impact of foreign currency translation	569
Gross goodwill, ending balance	569,237
Accumulated impairment losses	(16,166)
Goodwill net of accumulated impairment losses	553,071
Clinical Development Services
Goodwill [Roll Forward]
Gross goodwill, beginning balance	560,526
Accumulated impairment losses	(8,024)
Goodwill net of accumulated impairment losses	552,502
Impact of foreign currency translation	569
Gross goodwill, ending balance	561,095
Accumulated impairment losses	(8,024)
Goodwill net of accumulated impairment losses	553,071
Phase I Services
Goodwill [Roll Forward]
Gross goodwill, beginning balance	8,142
Accumulated impairment losses	(8,142)
Goodwill net of accumulated impairment losses	0
Impact of foreign currency translation	0
Gross goodwill, ending balance	8,142
Accumulated impairment losses	(8,142)
Goodwill net of accumulated impairment losses	$ 0