Schedule of Preferred Dividends Paid (Details) (USD $)	3 Months Ended
	Mar. 31, 2015
Class of Stock [Line Items]
For the Quarter Ended	Dec. 31, 2014
Record Date	Dec. 31, 2014
Payable Date	Jan. 15, 2015
7 1/2% Series H Preferred Shares [Member]
Class of Stock [Line Items]
Dividend per Share	0.47	[1]
For the Quarter Ended	Dec. 31, 2014
Record Date	Jan. 01, 2015
Payable Date	Jan. 15, 2015
6 3/8% Series I Preferred Stock [Member]
Class of Stock [Line Items]
Dividend per Share	0.40	[1]
For the Quarter Ended	Dec. 31, 2014
Record Date	Jan. 01, 2015
Payable Date	Jan. 15, 2015

[1] Amounts are rounded to the nearest whole cent for presentation purposes.