Summary of Significant Accounting Policies - Government Grant Income (Details) - Government Assistance, CARES Act - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Unusual or Infrequent Item, or Both [Line Items]
Government grant income received	$ 15	$ 2,448	$ 6,082	$ 17,332
Government grant income recorded in other income (expense), net
Unusual or Infrequent Item, or Both [Line Items]
Government grant income received	15	1,761	1,412	13,632
Government grant income recorded in equity income (loss) from unconsolidated joint ventures
Unusual or Infrequent Item, or Both [Line Items]
Government grant income received	0	295	1,010	1,099
Government grant income recorded in income (loss) from discontinued operations
Unusual or Infrequent Item, or Both [Line Items]
Government grant income received	$ 0	$ 392	$ 3,660	$ 2,601