Collaborative Arrangements and Acquisitions - Aggregate VIE Financial Information, Items Related to the Company's VIEs (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted cash and cash equivalents (VIE)	$ 1,803	$ 47,762
Prepaid expenses and other current assets	152,238	70,534
Intangible assets	29,000	284,340
Other assets	10,542	11,885
Accounts payable	77,138	61,451
Accrued expenses	378,554	315,249
Other liabilities, current portion	27,686	10,943
Deferred tax liability	10,682	134,063
Other liabilities, excluding current portion	26,029	28,699
Noncontrolling interest	12,167	181,609
Variable Interest Entity, Primary Beneficiary
Variable Interest Entity, Consolidated, Carrying Amount, Assets and Liabilities, Net [Abstract]
Restricted cash and cash equivalents (VIE)	1,803	47,762
Prepaid expenses and other current assets	42	6,812
Intangible assets	29,000	284,340
Other assets	280	399
Accounts payable	455	415
Accrued expenses	1,021	1,330
Other liabilities, current portion	119	2,137
Deferred tax liability	8,338	131,446
Other liabilities, excluding current portion	0	300
Noncontrolling interest	$ 12,167	$ 181,609