Mortgage Notes Payable - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Debt Instrument [Line Items]
Interest expense capitalized	$ 2,710	$ 4,331
Fair value of mortgage notes payable	4,209,689		$ 4,082,448
Green Acres Commons
Debt Instrument [Line Items]
Recourse mortgage notes	$ 65,000