Equity - Distributions Paid on a Percentage Basis (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Ordinary dividends	0.00%	45.00%	13.80%
Nondividend distributions	100.00%	37.20%	86.20%
Capital gain distributions	0.00%	17.80%	0.00%
Total	100.00%	100.00%	100.00%
Series F Preferred Stock [Member]
Class of Stock [Line Items]
Ordinary dividends	0.00%	71.70%	100.00%
Nondividend distributions	100.00%	0.00%	0.00%
Capital gain distributions	0.00%	28.30%	0.00%
Total	100.00%	100.00%	100.00%