Summary of Significant Accounting Policies - Government Grant Income (Details) - Government Assistance, CARES Act - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Unusual or Infrequent Item, or Both [Line Items]
Government grant income	$ 4,968	$ 0
Government grant income recorded in other income (expense), net
Unusual or Infrequent Item, or Both [Line Items]
Government grant income	1,310	0
Government grant income recorded in equity income (loss) from unconsolidated joint ventures
Unusual or Infrequent Item, or Both [Line Items]
Government grant income	426	0
Government grant income recorded in income (loss) from discontinued operations
Unusual or Infrequent Item, or Both [Line Items]
Government grant income	$ 3,232	$ 0