Fair Value Measurements - Level 3 Fair Value of Certain Assets Measured on a Non-recurring Basis (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Goodwill [Roll Forward]
43830	$ 182,377
Decrease from divestiture	(7,379)
Carrying value prior to impairment		$ 174,998
Impairment charge	(30,945)
Carrying value after impairment	144,053
Carrying value of assets not subject to impairment charge	94,073
Balance as of December 31, 2020	$ 238,126	$ 276,450	$ 198,622

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Goodwill, Gross, Excluding Assets Not Subject To Impairment Charge

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Goodwill, Gross, Subject To Impairment

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Goodwill, Gross, Subject to Impairment, Excluding Written off Related to Sale of Business Unit

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Goodwill, Net, Subject To Impairment

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