Equity - Series F Distributions Paid on a Percentage Basis (Details)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Ordinary dividends	95.00%	75.90%	6.00%
Nontaxable distributions	0.00%	0.00%	94.00%
Capital gain distributions	5.00%	24.10%	0.00%
Total	100.00%	100.00%	100.00%
Series F Preferred Stock [Member]
Class of Stock [Line Items]
Ordinary dividends	95.00%	75.90%	100.00%
Nontaxable distributions	0.00%	0.00%	0.00%
Capital gain distributions	5.00%	24.10%	0.00%
Total	100.00%	100.00%	100.00%