Summary of Significant Accounting Policies - Government Grant Income (Details) - Government Assistance, CARES Act - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule of Equity Method Investments [Line Items]
Government grant income	$ 2,448	$ 0	$ 17,332	$ 0
Other Income (Expense)
Schedule of Equity Method Investments [Line Items]
Government grant income	2,153	0	16,233	0
Equity Income (Loss) From Unconsolidated Joint Ventures
Schedule of Equity Method Investments [Line Items]
Government grant income	$ 295	$ 0	$ 1,099	$ 0