Notes Payable (Credit Facility) (Details) - Credit Facility	12 Months Ended
	Dec. 31, 2019 USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 1,000,000,000
Fixed charge coverage ratio	1.50
Remaining borrowing capacity	$ 748,500,000
Minimum
Line of Credit Facility [Line Items]
Unencumbered interest coverage ratio	1.75
Maximum
Line of Credit Facility [Line Items]
Secured leverage ratio (percent)	40.00%
Leverage ratio (percent)	60.00%
LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)	1.05%
LIBOR | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)	1.05%
LIBOR | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)	1.45%
Federal Funds Rate
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)	0.50%
One-month LIBOR
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)	1.00%
Base Rate | Minimum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)	0.10%
Base Rate | Maximum
Line of Credit Facility [Line Items]
Basis spread on variable rate (percent)	0.45%