Note 5 - Investment Securities - Trust Preferred Securities (Details) - USD ($)	9 Months Ended
	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
TPREF Funding II [Member]
Class / Tranche	Class B Notes
Amortized Cost	$ 725,000
Investment securities available for sale, at fair value	377,000
Unrealized Losses	$ (348,000)
Lowest Credit Rating Assigned	C
Number of Banks Currently Performing	19
Deferrals / Defaults as % of Current Balance	37.00%
Conditional Default Rates for 2015 and beyond	0.42%
Cumulative OTTI Life to Date	$ 274,000
TPREF Funding III [Member]
Class / Tranche	Class B2 Notes
Amortized Cost	$ 1,518,000
Investment securities available for sale, at fair value	804,000
Unrealized Losses	$ (714,000)
Lowest Credit Rating Assigned	C
Number of Banks Currently Performing	15
Deferrals / Defaults as % of Current Balance	32.00%
Conditional Default Rates for 2015 and beyond	0.43%
Cumulative OTTI Life to Date	$ 483,000
ALESCO Preferred Funding V [Member]
Class / Tranche	Class C1 Notes
Amortized Cost	$ 820,000
Investment securities available for sale, at fair value	510,000
Unrealized Losses	$ (310,000)
Lowest Credit Rating Assigned	C
Number of Banks Currently Performing	42
Deferrals / Defaults as % of Current Balance	14.00%
Conditional Default Rates for 2015 and beyond	0.41%
Cumulative OTTI Life to Date	$ 180,000
Collateralized Debt Obligations [Member]
Amortized Cost	3,063,000		$ 3,070,000
Investment securities available for sale, at fair value	1,691,000		1,883,000
Unrealized Losses	$ (1,372,000)		(1,187,000)
Number of Banks Currently Performing	76
Deferrals / Defaults as % of Current Balance	27.00%
Conditional Default Rates for 2015 and beyond
Cumulative OTTI Life to Date	$ 937,000
Amortized Cost	300,645,000		288,792,000
Investment securities available for sale, at fair value	299,385,000		284,795,000
Unrealized Losses	(3,846,000)		(5,396,000)
Cumulative OTTI Life to Date	$ 937,000	$ 935,000	$ 930,000	$ 930,000	$ 1,400,000	$ 3,966,000