Income Taxes (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Common Shares [Member]
Schedule Of Distributions Paid Per Common Share Of Beneficial Interest And Preferred Share On A Tax Basis [Line Items]
Ordinary Income Per Share	$ 0.6000	$ 0.4391	$ 0.4109
Percentage of Ordinary Income	100.00%	91.49%	100.00%
Capital Gain Per Share	$ 0.0000	$ 0.0000	$ 0.0000
Percentage of Capital Gain	0.00%	0.00%	0.00%
Return of Capital Per Share	$ 0.0000	$ 0.0409	$ 0.0000
Percentage of Return of Capital	0.00%	8.51%	0.00%
Distributions Paid Per Share on a Tax Basis	$ 0.6000	$ 0.4800	$ 0.4109
Percentage of Distributions Paid Per Share on a Tax Basis	100.00%	100.00%	100.00%
Series A Preferred Stock [Member]
Schedule Of Distributions Paid Per Common Share Of Beneficial Interest And Preferred Share On A Tax Basis [Line Items]
Ordinary Income Per Share	$ 2.0349	$ 1.7622	$ 1.3769
Percentage of Ordinary Income	100.00%	100.00%	100.00%
Capital Gain Per Share	$ 0.0000	$ 0.0000	$ 0.0000
Percentage of Capital Gain	0.00%	0.00%	0.00%
Return of Capital Per Share	$ 0.0000	$ 0.0000	$ 0.0000
Percentage of Return of Capital	0.00%	0.00%	0.00%
Distributions Paid Per Share on a Tax Basis	$ 2.0349	$ 1.7622	$ 1.3769
Percentage of Distributions Paid Per Share on a Tax Basis	100.00%	100.00%	100.00%
Current Year Distributions Carryforward to Next Year Distributions	$ 0.4261
Series B Preferred Stock [Member]
Schedule Of Distributions Paid Per Common Share Of Beneficial Interest And Preferred Share On A Tax Basis [Line Items]
Ordinary Income Per Share	$ 2.0672	$ 1.7902	$ 0.3431
Percentage of Ordinary Income	100.00%	100.00%	100.00%
Capital Gain Per Share	$ 0.0000	$ 0.0000	$ 0.0000
Percentage of Capital Gain	0.00%	0.00%	0.00%
Return of Capital Per Share	$ 0.0000	$ 0.0000	$ 0.0000
Percentage of Return of Capital	0.00%	0.00%	0.00%
Distributions Paid Per Share on a Tax Basis	$ 2.0672	$ 1.7902	$ 0.3431
Percentage of Distributions Paid Per Share on a Tax Basis	100.00%	100.00%	100.00%
Current Year Distributions Carryforward to Next Year Distributions	$ 0.4328
Series C Preferred Stock [Member]
Schedule Of Distributions Paid Per Common Share Of Beneficial Interest And Preferred Share On A Tax Basis [Line Items]
Ordinary Income Per Share	$ 0.9890	$ 0.0000	$ 0.0000
Percentage of Ordinary Income	100.00%	0.00%	0.00%
Capital Gain Per Share	$ 0.0000	$ 0.0000	$ 0.0000
Percentage of Capital Gain	0.00%	0.00%	0.00%
Return of Capital Per Share	$ 0.0000	$ 0.0000	$ 0.0000
Percentage of Return of Capital	0.00%	0.00%	0.00%
Distributions Paid Per Share on a Tax Basis	$ 0.9890	$ 0.0000	$ 0.0000
Percentage of Distributions Paid Per Share on a Tax Basis	100.00%	0.00%	0.00%
Current Year Distributions Carryforward to Next Year Distributions	$ 0.3517