Income Taxes - Federal Income Tax Treatment of Common Dividends (Details) - Common Stock - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax [Line Items]
Ordinary Income (A)	$ 0.5800	$ 0.7650	$ 0.6858
Unrecaptured Section 1250 Capital Gain	0.2576	0.1074	0.1497
Other Capital Gain	0.1624	0.0460	0.0330
Qualified Dividend	0	0.0016	0.0015
Distributions Per Common Share	$ 1.0000	$ 0.9200	$ 0.8700
Ordinary Income as a Percentage of Distributions	58.00%	83.15%	78.83%
Unrecaptured Section 1250 Gain as a Percentage of Distributions	25.76%	11.68%	17.21%
Capital Gain as a Percentage of Distributions	16.24%	5.00%	3.79%
Qualified Dividend as a Percentage Of Distributions	0.00%	0.17%	0.17%
Common Distributions Percentage	100.00%	100.00%	100.00%