Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Boston-based Dataxu, Inc, Demand-Side Platform (DSP)
Finite Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 3.6	$ 0.1	$ 7.4	$ 0.3

The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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