Stockholders' Equity (Distributions) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Dividends Payable [Line Items]
Dividends, percent	100.00%	100.00%	100.00%
Dividends paid (in usd per share)	$ 0.85	$ 0.95	$ 1.51
Return of capital
Dividends Payable [Line Items]
Dividends, percent	100.00%	100.00%	99.70%
Dividends paid (in usd per share)	$ 0.85	$ 0.95	$ 1.50
Capital gain dividend income
Dividends Payable [Line Items]
Dividends, percent	0.00%	0.00%	0.30%
Dividends paid (in usd per share)	$ 0	$ 0	$ 0.01
Ordinary dividend income
Dividends Payable [Line Items]
Dividends, percent	0.00%	0.00%	0.00%
Dividends paid (in usd per share)	$ 0	$ 0	$ 0