Real Estate Transactions - Casualty-Related Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Real Estate [Line Items]
Casualty-related loss, net insurance proceeds	$ 11,000	$ 0	$ (9,912)
Property damage related to casualty loss	6,000
Other associated costs related to casualty loss	5,000
Deferred tax benefit associated with casualty related losses	2,000
Other income (expense), net
Real Estate [Line Items]
Casualty-related loss, net insurance proceeds	10,000
Equity income (loss) from unconsolidated joint ventures
Real Estate [Line Items]
Casualty-related loss, net insurance proceeds	$ 1,000