Line of Credit Payable (Details)	9 Months Ended
	Sep. 30, 2019 USD ($)
Line of Credit Facility [Line Items]
Revolving credit facility borrowing capacity	$ 900,000,000
Line of Credit
Line of Credit Facility [Line Items]
Revolving credit facility borrowing capacity	900,000,000
Revolving credit facility weighted average outstanding balance	$ 8,443,000
Revolving credit facility weighted average interest rate	3.20%
Option to increase facility size	$ 1,600,000,000
Line of credit payable	0
Line of credit facility available for future borrowings	$ 900,000,000
Line of Credit | LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate	0.875%