Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Book value	$ 347,478,000	$ 373,844,000
Investment securities available-for-sale	350,810,000	375,219,000
PreTSL IV [Member]
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Class	Mezzanine*
Book value	243,000
Investment securities available-for-sale	208,000
Unrealized gains (losses)	(35,000)
Total recognized OTTI credit loss	(1,000)
Moody's/Fitch ratings	B1/B
Current number of performing banks	5
Actual deferrals and defaults as a % of total collateral	18.00%
Total performing collateral as a % of outstanding bonds	140.20%
PreTSL XVII [Member]
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Class	Mezzanine
Book value	752,000
Investment securities available-for-sale	535,000
Unrealized gains (losses)	(217,000)
Total recognized OTTI credit loss	(222,000)
Moody's/Fitch ratings	C/C
Current number of performing banks	32
Current number of performing insurance companies	5
Actual deferrals and defaults as a % of total collateral	28.60%
Total performing collateral as a % of outstanding bonds	86.60%
PreTSL XIX [Member]
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Class	Mezzanine
Book value	988,000
Investment securities available-for-sale	527,000
Unrealized gains (losses)	(461,000)
Total recognized OTTI credit loss	0
Moody's/Fitch ratings	C/C
Current number of performing banks	38
Current number of performing insurance companies	12
Actual deferrals and defaults as a % of total collateral	13.30%
Total performing collateral as a % of outstanding bonds	92.80%
PreTSL XXV [Member]
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Class	Mezzanine
Book value	766,000
Investment securities available-for-sale	454,000
Unrealized gains (losses)	(312,000)
Total recognized OTTI credit loss	(222,000)
Moody's/Fitch ratings	C/C
Current number of performing banks	46
Current number of performing insurance companies	5
Actual deferrals and defaults as a % of total collateral	28.30%
Total performing collateral as a % of outstanding bonds	87.50%
PreTSL XXVI [Member] | Security 1 [Member]
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Class	Mezzanine
Book value	469,000
Investment securities available-for-sale	357,000
Unrealized gains (losses)	(112,000)
Total recognized OTTI credit loss	(270,000)
Moody's/Fitch ratings	C/C
Current number of performing banks	42
Current number of performing insurance companies	7
Actual deferrals and defaults as a % of total collateral	23.70%
Total performing collateral as a % of outstanding bonds	93.70%
PreTSL XXVI [Member] | Security 2 [Member]
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Class	Mezzanine
Book value	301,000
Investment securities available-for-sale	493,000
Unrealized gains (losses)	192,000
Total recognized OTTI credit loss	(438,000)
Moody's/Fitch ratings	C/C
Current number of performing banks	42
Current number of performing insurance companies	7
Actual deferrals and defaults as a % of total collateral	23.70%
Total performing collateral as a % of outstanding bonds	93.70%
Collateralized Debt Obligations [Member]
Note 7 - Investment Securities (Details) - Pooled Trust Preferred Securities [Line Items]
Book value	3,519,000	3,519,000
Investment securities available-for-sale	2,574,000	2,439,000
Unrealized gains (losses)	(945,000)
Total recognized OTTI credit loss	$ (1,153,000)