Collaborative Arrangements and Acquisitions - Aggregate VIE Financial Information, Summary of Net Income Attributable to Noncontrolling Interest (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
Provision for income taxes	$ 4,337	$ 18,130	$ 8,322	$ 23,615
Net income attributable to noncontrolling interest	13,173	28,374	14,965	33,903
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
(Income) loss attributable to noncontrolling interest before provision for income taxes and changes in fair value of contingent payments	(18,045)	2,835	(16,498)	3,674
Provision for income taxes	8,132	17,511	8,523	20,573
Increase in fair value of contingent payments	(3,260)	(48,720)	(6,990)	(58,150)
Net income attributable to noncontrolling interest	$ 13,173	$ 28,374	$ 14,965	$ 33,903