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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Other Assets - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Dec. 31, 2027	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2020	Dec. 31, 2019
Schedule of Other Assets [Line Items]
Prepaid expenses, net of current portion		$ 26,118		$ 26,118			$ 191
Capital contributions		$ 75	$ 366	$ 368	$ 878
Minimum
Schedule of Other Assets [Line Items]
Ownership percentage		3.00%		3.00%
Maximum
Schedule of Other Assets [Line Items]
Ownership percentage		5.00%		5.00%
Scenario, Forecast
Schedule of Other Assets [Line Items]
Capital contributions	$ 2,000
Jack Welch Management Institute
Schedule of Other Assets [Line Items]
Prepaid expenses, net of current portion		$ 21,000		$ 21,000
Prepaid expense, amortization period				15 years
Funds received from investor				$ 2,800
Jack Welch Management Institute \| Scenario, Forecast
Schedule of Other Assets [Line Items]
Commitment for future services under the perpetual license agreement						$ 25,300