CONSOLIDATED STATEMENTS OF EQUITY (Parenthetical) - $ / shares	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2018
Common stock, dividend per share paid (in dollars per share)	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 0.21	$ 0.21
Preferred shares, par value (in dollars per share)	0.01	0.01	0.01	0.01	0.01	0.01
Common stock, par value (in dollars per share)	1.00	1.00	1.00	1.00	1.00	1.00	$ 1.00
Series B Preferred Stock
Preferred stock, dividends per share paid (in dollars per share)	0.4609	0.4609	0.4609	0.4609	0.4609	0.4609
Preferred shares, par value (in dollars per share)	0.01	0.01	0.01	0.01	0.01	0.01	0.01
Series C Preferred Stock
Preferred stock, dividends per share paid (in dollars per share)	0.45	0.45	0.45	0.4500	0.4500	0.4500
Preferred shares, par value (in dollars per share)	0.01	0.01	0.01	0.01	0.01	0.01	0.01
Series D Preferred Stock
Preferred stock, dividends per share paid (in dollars per share)	0.4297	0.4297	0.4297	0.4297	0.4297	0.4297
Preferred shares, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 0.01