Note 5 - Investment Securities (Details) - Trust Preferred Securities $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Note 5 - Investment Securities (Details) - Trust Preferred Securities [Line Items]
Amortized cost	$ 261,249	$ 288,792
Fair value	260,269	284,795
Unrealized losses	(3,802)	(5,396)
Cumulative OTTI life to date	$ 931	930	$ 3,969	$ 3,966
TPREF Funding II [Member]
Note 5 - Investment Securities (Details) - Trust Preferred Securities [Line Items]
Class / tranche	Class B Notes
Amortized cost	$ 731
Fair value	414
Unrealized losses	$ (317)
Lowest credit rating assigned	C
Number of banks currently performing	19
Deferrals / defaults as % of current balance	37.00%
Conditional default rates for 2013 and beyond	0.42%
Cumulative OTTI life to date	$ 268
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	888
Unrealized losses	$ (630)
Lowest credit rating assigned	C
Number of banks currently performing	15
Deferrals / defaults as % of current balance	32.00%
Conditional default rates for 2013 and beyond	0.41%
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	556
Unrealized losses	$ (264)
Lowest credit rating assigned	C
Number of banks currently performing	42
Deferrals / defaults as % of current balance	19.00%
Conditional default rates for 2013 and beyond	0.37%
Cumulative OTTI life to date	$ 180
Collateralized Debt Obligations [Member]
Note 5 - Investment Securities (Details) - Trust Preferred Securities [Line Items]
Amortized cost	3,069	3,070
Fair value	1,858	1,883
Unrealized losses	$ (1,211)	$ (1,187)
Number of banks currently performing	76
Deferrals / defaults as % of current balance	29.00%
Cumulative OTTI life to date	$ 931