Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Series C Preferred Stock
Preferred stock, dividends paid (usd per share)	$ 1.75	$ 1.75	$ 1.75
Series D Preferred Stock
Preferred stock, dividends paid (usd per share)	1.63	1.63	1.63
Series E Preferred Stock
Preferred stock, dividends paid (usd per share)	1.61	1.61	1.61
Series F Preferred Stock
Preferred stock, dividends paid (usd per share)	$ 1.50	$ 1.50	$ 1.50