Subsequent Events (Details) - USD ($)	1 Months Ended	9 Months Ended
	Oct. 31, 2017	Sep. 30, 2017
Subsequent Event [Line Items]
Revolving credit facility borrowing capacity		$ 650,000,000
Option to increase facility size		$ 1,000,000,000
Line of Credit | LIBOR
Subsequent Event [Line Items]
Basis spread on variable rate		0.925%
Amended Credit Facility | Line of Credit
Subsequent Event [Line Items]
Revolving credit facility borrowing capacity		$ 650,000,000
Amended Credit Facility | Line of Credit | Subsequent Event
Subsequent Event [Line Items]
Revolving credit facility borrowing capacity	$ 900,000,000
Option to increase facility size	$ 1,600,000,000
Amended Credit Facility | Line of Credit | LIBOR | Subsequent Event
Subsequent Event [Line Items]
Basis spread on variable rate	0.875%
Notes Payable Due October 2017 | Line of Credit
Subsequent Event [Line Items]
Interest rate, stated percentage		6.875%
Notes Payable Due October 2017 | Line of Credit | Subsequent Event
Subsequent Event [Line Items]
Repayments of notes payable	$ 250,000,000