Collaborative Arrangements and Acquisitions - Aggregate VIE Financial Information, Summary of Net Income Attributable to noncontrolling (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
(Benefit from) provision for income taxes	$ 10,341	$ 4,337	$ (2,318)	$ 8,322
Net loss (income) attributable to noncontrolling interest	1,110	(13,173)	(15,928)	(14,965)
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity, Primary Beneficiary, Does Not Hold Majority Voting Interest, Disclosures [Abstract]
Loss (income) attributable to noncontrolling interest before (benefit from) provision for income taxes and changes in fair value of contingent payments	426	(18,045)	983	(16,498)
(Benefit from) provision for income taxes	(416)	8,132	5,989	8,523
Decrease (increase) in fair value of contingent payments	1,100	(3,260)	(22,900)	(6,990)
Net loss (income) attributable to noncontrolling interest	$ 1,110	$ (13,173)	$ (15,928)	$ (14,965)