Consolidated Statements of Changes in Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Cash dividends declared on common shares (in usd per share)	$ 0.17	$ 0.095	$ 0.395	$ 0.275
Series A Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)				1.9375
Series C Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)				0.539063
Series D Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)	12.50	12.50	37.50	37.50
Series E Preferred Stock [Member]
Cash dividends declared on Preferred Stock (in usd per share)	$ 0.382813	$ 0.382813	$ 1.148439	$ 1.161199