Other Data - Characterization of Distributions (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Characterization of distributions on common stock
Ordinary income (in USD per share)	$ 0.79	$ 0.75	$ 0.42
Return of capital (in USD per share)	0.40	0.33	0.50
Unrecaptured section 1250 gain (in USD per share)	0.01	0.12	0.28
Common stock distributions(in USD per share)	$ 1.20	$ 1.20	$ 1.20
Ordinary income in percent of common stock distribution	65.70%	62.20%	34.50%
Return of capital in percent of common stock distribution	33.90%	27.80%	42.00%
Unrecaptured section 1250 gain in percent of common stock distribution	0.40%	10.00%	23.50%
Common stock distribution in percentage	100.00%	100.00%	100.00%