Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid [Line Items]
Dividends distributed, amount	$ 400,354	$ 382,722	$ 353,764
Series F Preferred Stock [Member]
Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid [Line Items]
Ordinary income, amount		9,116	11,638
Ordinary income, percent		94.00%	100.00%
Capital gain, amount		582
Capital gain, percent		6.00%
Dividends distributed, amount		9,698	11,638
Dividends distributed, percent		100.00%	100.00%
Series G Preferred Stock [Member]
Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid [Line Items]
Ordinary income, amount		33,046	35,650
Ordinary income, percent		94.00%	100.00%
Capital gain, amount		2,109
Capital gain, percent		6.00%
Dividends distributed, amount		35,155	35,650
Dividends distributed, percent		100.00%	100.00%
Series H Preferred Stock [Member]
Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid [Line Items]
Ordinary income, amount	8,694	11,351	13,584
Ordinary income, percent	72.00%	94.00%	100.00%
Capital gain, amount	3,381	725
Capital gain, percent	28.00%	6.00%
Dividends distributed, amount	12,075	12,076	13,584
Dividends distributed, percent	100.00%	100.00%	100.00%
Series I Preferred Stock [Member]
Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid [Line Items]
Ordinary income, amount	17,280	12,847
Ordinary income, percent	72.00%	94.00%
Capital gain, amount	6,720	820
Capital gain, percent	28.00%	6.00%
Dividends distributed, amount	24,000	13,667
Dividends distributed, percent	100.00%	100.00%
Series J Preferred Stock [Member]
Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid [Line Items]
Ordinary income, amount	8,910	2,585
Ordinary income, percent	72.00%	94.00%
Capital gain, amount	3,465	165
Capital gain, percent	28.00%	6.00%
Dividends distributed, amount	12,375	2,750
Dividends distributed, percent	100.00%	100.00%
Series K Preferred Stock [Member]
Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid [Line Items]
Ordinary income, amount	6,064
Ordinary income, percent	72.00%
Capital gain, amount	2,358
Capital gain, percent	28.00%
Dividends distributed, amount	8,422
Dividends distributed, percent	100.00%
Common Stock [Member]
Note 21 - Income Taxes (Details) - Taxable Characteristics of Distributions Paid [Line Items]
Ordinary income, amount	158,001	222,751	208,832
Ordinary income, percent	46.00%	72.00%	71.00%
Capital gain, amount	61,827	15,469
Capital gain, percent	18.00%	5.00%
Return of capital	123,654	71,156	84,060
Return of capital	36.00%	23.00%	29.00%
Dividends distributed, amount	$ 343,482	$ 309,376	$ 292,892
Dividends distributed, percent	100.00%	100.00%	100.00%