Note 22 - Income Taxes (Detail) - Taxable Characteristics of Distributions Paid (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Dividends distributed, amount	$ 382,722	$ 353,764	$ 306,964
Series F Preferred Stock [Member]
Ordinary income, amount	9,116	11,638	11,638
Ordinary income, percent	94.00%	100.00%	100.00%
Capital gain, amount	582
Capital gain, percent	6.00%
Dividends distributed, amount	9,698	11,638	11,638
Dividends distributed, percent	100.00%	100.00%	100.00%
Series G Preferred Stock [Member]
Ordinary income, amount	33,046	35,650	35,650
Ordinary income, percent	94.00%	100.00%	100.00%
Capital gain, amount	2,109
Capital gain, percent	6.00%
Dividends distributed, amount	35,155	35,650	35,650
Dividends distributed, percent	100.00%	100.00%	100.00%
Series H Preferred Stock [Member]
Ordinary income, amount	11,351	13,584
Ordinary income, percent	94.00%	100.00%
Capital gain, amount	725
Capital gain, percent	6.00%
Dividends distributed, amount	12,076	13,584
Dividends distributed, percent	100.00%	100.00%
Series I Preferred Stock [Member]
Ordinary income, amount	12,847
Ordinary income, percent	94.00%
Capital gain, amount	820
Capital gain, percent	6.00%
Dividends distributed, amount	13,667
Dividends distributed, percent	100.00%
Series J Preferred Stock [Member]
Ordinary income, amount	2,585
Ordinary income, percent	94.00%
Capital gain, amount	165
Capital gain, percent	6.00%
Dividends distributed, amount	2,750
Dividends distributed, percent	100.00%
Common Stock [Member]
Ordinary income, amount	222,751	208,832	181,773
Ordinary income, percent	72.00%	71.00%	70.00%
Capital gain, amount	15,469
Capital gain, percent	5.00%
Return of capital	71,156	84,060	77,903
Return of capital	23.00%	29.00%	30.00%
Dividends distributed, amount	$ 309,376	$ 292,892	$ 259,676
Dividends distributed, percent	100.00%	100.00%	100.00%