Note 16 - Preferred Stock, Common Stock and Convertible Unit Transactions (Details) - Preferred Stock Issued - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Note 16 - Preferred Stock, Common Stock and Convertible Unit Transactions (Details) - Preferred Stock Issued [Line Items]
Net Proceeds (in Dollars)		$ 493	$ 14,047		$ 9,213
Series I Preferred Stock [Member]
Note 16 - Preferred Stock, Common Stock and Convertible Unit Transactions (Details) - Preferred Stock Issued [Line Items]
Depositary Shares Issued	[1]	16,000,000	16,000,000
Net Proceeds (in Dollars)	[1]	$ 387,200	$ 387,200
Offering/ Redemption Price (in Dollars per share)	[1]	$ 25.00	$ 25.00
Series J Preferred Stock [Member]
Note 16 - Preferred Stock, Common Stock and Convertible Unit Transactions (Details) - Preferred Stock Issued [Line Items]
Depositary Shares Issued	[2]	9,000,000	9,000,000
Net Proceeds (in Dollars)	[2]	$ 217,800	$ 217,800
Offering/ Redemption Price (in Dollars per share)	[2]	$ 25.00	$ 25.00
Series K Preferred Stock [Member]
Note 16 - Preferred Stock, Common Stock and Convertible Unit Transactions (Details) - Preferred Stock Issued [Line Items]
Depositary Shares Issued	[2]	7,000,000	7,000,000
Net Proceeds (in Dollars)	[2]	$ 169,100	$ 169,100
Offering/ Redemption Price (in Dollars per share)	[2]	$ 25.00	$ 25.00
Series H Preferred Stock [Member]
Note 16 - Preferred Stock, Common Stock and Convertible Unit Transactions (Details) - Preferred Stock Issued [Line Items]
Depositary Shares Issued	[3]		7,000,000
Net Proceeds (in Dollars)	[3]		$ 169,200
Offering/ Redemption Price (in Dollars per share)		$ 25.00	$ 25.00	[3]

[1] The net proceeds received from this offering were used for the redemption of all the outstanding depositary shares representing the Company's Class F preferred stock, which redemption occurred on August 15, 2012 with the remaining proceeds used towards the redemption of outstanding depositary shares representing the Company's Class G preferred stock, which redemption occurred on October 10, 2012 and general corporate purposes.

[2] The net proceeds received from this offering were used for general corporate purposes, including funding towards the repayment of maturing Senior Unsecured Notes.

[3] The net proceeds received from this offering were used for general corporate purposes, including the reduction of borrowings outstanding under the Company's revolving credit facility and the redemption of shares of the Company's preferred stock.