Debt - Components of Mortgage Debt (Footnotes) (Details) - Senior Unsecured Revolving Credit Facility		12 Months Ended
	Mar. 08, 2018	Dec. 31, 2019
Minimum
Participating Mortgage Loans [Line Items]
Debt instrument, basis spread on variable rate	0.00%
Maximum
Participating Mortgage Loans [Line Items]
Debt instrument, basis spread on variable rate	1500.00%
LIBOR | Minimum
Participating Mortgage Loans [Line Items]
Debt instrument, basis spread on variable rate		1.55%
LIBOR | Maximum
Participating Mortgage Loans [Line Items]
Debt instrument, basis spread on variable rate		2.30%
Prime Rate | Minimum
Participating Mortgage Loans [Line Items]
Debt instrument, basis spread on variable rate		0.55%
Prime Rate | Maximum
Participating Mortgage Loans [Line Items]
Debt instrument, basis spread on variable rate		1.30%