Note 12 - Preferred Stock (Details) - Outstanding Preferred Stock - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Note 12 - Preferred Stock (Details) - Outstanding Preferred Stock [Line Items]
Shares Authorized	5,959,100	5,959,100
Liquidation Preference (in Dollars)	$ 975,000	$ 975,000
Par Value (in Dollars per share)	$ 1.00	$ 1.00
Series H Preferred Stock [Member]
Note 12 - Preferred Stock (Details) - Outstanding Preferred Stock [Line Items]
Shares Authorized	70,000
Shares Outstanding	70,000
Liquidation Preference (in Dollars)	$ 175,000
Dividend Rate	6.90%
Dividend Payout (in Dollars per share)	$ 1.72500
Par Value (in Dollars per share)	$ 1.00
Series I Preferred Stock [Member]
Note 12 - Preferred Stock (Details) - Outstanding Preferred Stock [Line Items]
Shares Authorized	18,400
Shares Outstanding	16,000
Liquidation Preference (in Dollars)	$ 400,000
Dividend Rate	6.00%
Dividend Payout (in Dollars per share)	$ 1.50000
Par Value (in Dollars per share)	$ 1.00
Series J Preferred Stock [Member]
Note 12 - Preferred Stock (Details) - Outstanding Preferred Stock [Line Items]
Shares Authorized	9,000
Shares Outstanding	9,000
Liquidation Preference (in Dollars)	$ 225,000
Dividend Rate	5.50%
Dividend Payout (in Dollars per share)	$ 1.37500
Par Value (in Dollars per share)	$ 1.00
Series K Preferred Stock [Member]
Note 12 - Preferred Stock (Details) - Outstanding Preferred Stock [Line Items]
Shares Authorized	8,050
Shares Outstanding	7,000
Liquidation Preference (in Dollars)	$ 175,000
Dividend Rate	5.625%
Dividend Payout (in Dollars per share)	$ 1.40625
Par Value (in Dollars per share)	$ 1.00
Total [Member]
Note 12 - Preferred Stock (Details) - Outstanding Preferred Stock [Line Items]
Shares Authorized	105,450
Shares Outstanding	102,000
Liquidation Preference (in Dollars)	$ 975,000