Consolidated Statements of Shareholders' Equity (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Dividends on common stock per share	$ 0.32	$ 0.28
8% Preferred Stock
Preferred stock, dividend rate (as a percent)	8.00%
Dividends on preferred stock per share	$ 80.00	$ 80.00
7% Preferred Stock
Preferred stock, dividend rate (as a percent)	7.00%
Dividends on preferred stock per share	$ 1.75
Offering expenses on issuance of stock		$ 1,731
6% Preferred Stock
Preferred stock, dividend rate (as a percent)	6.00%
Dividends on preferred stock per share	$ 60.00