Note 5 - Investment Securities (Details) - Trust Preferred Securities $ in Thousands	9 Months Ended
	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)
Note 5 - Investment Securities (Details) - Trust Preferred Securities [Line Items]
Amortized cost	$ 209,778	$ 185,250
Fair value	209,119	185,379
Unrealized losses	(2,871)	(2,271)
Cumulative OTTI life to date	$ 930	3,966	$ 3,966	$ 3,959
TPREF Funding II [Member]
Note 5 - Investment Securities (Details) - Trust Preferred Securities [Line Items]
Class / tranche	Class B Notes
Amortized cost	$ 732
Fair value	395
Unrealized losses	$ (337)
Lowest credit rating assigned	C
Number of banks currently performing	20
Deferrals / defaults as % of current balance	36.00%
Conditional default rates for 2013 and beyond	0.38%
Cumulative OTTI life to date	$ 267
TPREF Funding III [Member]
Note 5 - Investment Securities (Details) - Trust Preferred Securities [Line Items]
Class / tranche	Class B2 Notes
Amortized cost	$ 1,518
Fair value	815
Unrealized losses	$ (703)
Lowest credit rating assigned	C
Number of banks currently performing	16
Deferrals / defaults as % of current balance	29.00%
Conditional default rates for 2013 and beyond	0.40%
Cumulative OTTI life to date	$ 483
ALESCO Preferred Funding V [Member]
Note 5 - Investment Securities (Details) - Trust Preferred Securities [Line Items]
Class / tranche	Class C1 Notes
Amortized cost	$ 820
Fair value	460
Unrealized losses	$ (360)
Lowest credit rating assigned	C
Number of banks currently performing	40
Deferrals / defaults as % of current balance	15.00%
Conditional default rates for 2013 and beyond	0.34%
Cumulative OTTI life to date	$ 180
Collateralized Debt Obligations [Member]
Note 5 - Investment Securities (Details) - Trust Preferred Securities [Line Items]
Amortized cost	3,070	5,261
Fair value	1,670	3,193
Unrealized losses	$ (1,400)	$ (2,068)
Number of banks currently performing	76
Deferrals / defaults as % of current balance	27.00%
Cumulative OTTI life to date	$ 930