Discontinued Operations previously held for sale Additional Information (Details) - USD ($) $ in Thousands			3 Months Ended		9 Months Ended		12 Months Ended
	Jun. 19, 2019	Dec. 05, 2017	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (Loss) On Disposition Of Business Interests Before Tax					$ (16,252)	$ (23,022)
Proceeds from Divestiture of Businesses	$ 4,465,476
Proceeds from Divestiture of Businesses, Net of Cash Divested	$ 3,824,509
Discontinued Operations, Held-for-sale | DMG held for sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Business acquisition, Effective date of divestiture	Jun. 19, 2019
Purchase and Sale Agreement, Aggregate purchase price	$ 4,340,000
Business Acquisition, Date of Acquisition Agreement		Dec. 05, 2017
Gain (Loss) On Disposition Of Business Interests Before Tax			$ 0	$ 0		$ (23,022)	$ (23,022)
Coronavirus Aid Relief And Economic Security Act Additional Tax Benefit | Discontinued Operations, Held-for-sale | DMG held for sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (Loss) On Disposition Of Business Interests Before Tax					$ 9,980