Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities (USD $)	6 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 PreTSL IV [Member]		Jun. 30, 2014 PreTSL V [Member]		Jun. 30, 2014 PreTSL XVII [Member]	Jun. 30, 2014 PreTSL XIX [Member]	Jun. 30, 2014 PreTSL XXV [Member]	Jun. 30, 2014 PreTSL XXVI [Member]	Jun. 30, 2014 PreTSL XXVII [Member]	Jun. 30, 2014 Pooled Trust Preferred Securities [Member]	Dec. 31, 2013 Pooled Trust Preferred Securities [Member]
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Class				Mezzanine*	[1]	Mezzanine*	[1]	Mezzanine	Mezzanine	Mezzanine	Mezzanine	Mezzanine
Book value		$ 343,573,000	$ 393,840,000	$ 243,000				$ 752,000	$ 988,000	$ 766,000	$ 469,000	$ 301,000	$ 3,519,000	$ 3,519,000
Available-for-sale Securities		344,277,000	388,670,000	205,000				492,000	497,000	413,000	335,000	451,000	2,393,000	2,069,000
Unrealized gains (losses)				(38,000)				(260,000)	(491,000)	(353,000)	(134,000)	150,000	(1,126,000)
Total recognized OTTI credit loss	$ 43,000			$ (1,000)		$ (118,000)	[1]	$ (222,000)	$ 0	$ (222,000)	$ (270,000)	$ (438,000)	$ (1,271,000)
Moody's/Fitch ratings				B1/B		C/D	[1]	C/C	C/C	C/C	C/C	C/C
Current number of performing banks				5				32	38	45	40	40
Current number of performing insurance companies								5	12	6	7	7
Actual deferrals and defaults as a % of total collateral				18.00%		100.00%	[1]	29.10%	15.90%	29.30%	29.00%	29.00%
Total performing collateral as a % of outstanding bonds				140.00%		13.20%	[1]	84.40%	87.90%	86.40%	86.20%	86.20%

[1] Mezzanine* - only class of bonds still outstanding (represents the senior-most obligation of the trust)