Impairment Charges (Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
Jun. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Impairment charges	$ 25,100	$ 122,227	$ 106,603	$ 4,486
Impairment charge		25,062	97,996
impairments of intangibles and property and equipment associated with the sale of a subsidiary		97,100	8,600
AMCNI Reporting Unit [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment charges			4,500
Impairment charge		$ 25,100	$ 98,000

Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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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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The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

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