Stockholders' Equity - Common and Preferred Stock Dividends (Details) - $ / shares	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Common stock
Class of Stock
Declaration Date	Apr. 29, 2020	May 06, 2019	Feb. 20, 2020	Feb. 25, 2019
Common Stock, Dividend Per Share	$ 0.05	$ 0.04	$ 0.05	$ 0.04
Preferred Stock Series A
Class of Stock
Declaration Date	Apr. 29, 2020	May 06, 2019	Feb. 20, 2020	Feb. 25, 2019
Preferred Stock, Dividend Per Share	$ 0.46875	$ 0.46875	$ 0.46875	$ 0.46875
Preferred Stock Series B
Class of Stock
Declaration Date	Apr. 29, 2020	May 06, 2019	Feb. 20, 2020	Feb. 25, 2019
Preferred Stock, Dividend Per Share	$ 18.75	$ 18.75	$ 18.75	$ 18.75
Preferred Stock, Dividend Per Depositary Share	$ 0.46875	$ 0.46875	$ 0.46875	$ 0.46875
Preferred Stock Series C
Class of Stock
Declaration Date	Apr. 29, 2020	May 06, 2019	Feb. 20, 2020	Feb. 25, 2019
Preferred Stock, Dividend Per Share	$ 18.75	$ 18.75	$ 18.75	$ 18.75
Preferred Stock, Dividend Per Depositary Share	$ 0.46875	$ 0.46875	$ 0.46875	$ 0.46875
Preferred Stock Series D
Class of Stock
Declaration Date	Apr. 29, 2020			May 06, 2019
Preferred Stock, Dividend Per Share	$ 8,750.00			$ 8,750.00