Debt - Narrative (Details)	1 Months Ended	9 Months Ended
	Jan. 31, 2017 USD ($) extension	Sep. 30, 2017 USD ($) instrument	Dec. 31, 2016 USD ($)
Unsecured Debt [Member]
Debt Instrument [Line Items]
Unamortized discount (premium), net		$ 5,000,000	$ 100,000
Unamortized debt issuance expense		18,900,000	18,100,000
Lines of credit, net [Member]
Debt Instrument [Line Items]
Unamortized debt issuance expense		$ 3,400,000	3,300,000
Number of lines of unsecured credit (in instruments) | instrument		2
Aggregate borrowing capacity		$ 1,030,000,000
Lines of credit, net [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Aggregate borrowing capacity	$ 1,000,000,000
Number of extension options (in extensions) | extension	1
Extension period (in months)	18 months
Lines of credit, net [Member] | Line of Credit [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)		0.90%
Lines of credit, net [Member] | Line of Credit Working Capital [Member]
Debt Instrument [Line Items]
Aggregate borrowing capacity		$ 25,000,000
Lines of credit, net [Member] | Line of Credit Working Capital [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)		0.90%
Mortgage notes payable, net [Member]
Debt Instrument [Line Items]
Unamortized discount (premium), net		$ 37,400,000	50,800,000
Unamortized debt issuance expense		$ 6,000,000	$ 7,400,000