Stockholders' Equity - Dividends Declared (Details) - $ / shares		3 Months Ended				9 Months Ended
	Jun. 10, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Class of Stock [Line Items]
Dividends declared (in dollars per share)		$ 0.46			$ 0.46	$ 1.38	$ 1.38
Common stock
Class of Stock [Line Items]
Dividends declared (in dollars per share)		0.46	$ 0.46	$ 0.46
Series B Preferred Stock
Class of Stock [Line Items]
Dividends declared (in dollars per share)		$ 0.50	0.50	0.50
Series C Preferred Stock
Class of Stock [Line Items]
Dividends declared (in dollars per share)	$ 0.2223		$ 0.22	$ 0.50