Acquired Intangible Assets - Change in Carrying Value of Acquired Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-lived Intangible Assets [Roll Forward]
Beginning balance	$ 77,102	$ 14,334	$ 19,292
Acquisitions	14,559	75,871	2,657
Amortization of Acquired Intangible Assets	(15,000)	(13,103)	(7,615)
Sale of asset group	(7,582)	0	0
Ending balance	$ 69,079	$ 77,102	$ 14,334