Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position [Line Items]
Available for sale securities in a continuous unrealized loss position, less than 12 months, fair value	$ 70,535	$ 146,024
Available for sale securities in a continuous unrealized loss position, less than 12 months, unrealized losses	2,347	4,086
Available for sale securities in a continuous unrealized loss position, 12 months or more, fair value	21,990	12,151
Available for sale securities in a continuous unrealized loss position, 12 months or more, unrealized losses	1,455	1,310
Available for sale securities in a continuous unrealized loss position, fair value	92,525	158,175
Available for sale securities in a continuous unrealized loss position, unrealized losses	3,802	5,396
Held to maturity securities in a continuous unrealized loss position, less than 12 months, fair value	28,604	88,553
Held to maturity securities in a continuous unrealized loss position, less than 12 months, unrealized losses	166	825
Held to maturity securities in a continuous unrealized loss position, 12 months or more, fair value	0	15,956
Held to maturity securities in a continuous unrealized loss position, 12 months or more, unrealized losses	0	48
Held to maturity securities in a continuous unrealized loss position, fair value	28,604	104,509
Held to maturity securities in a continuous unrealized loss position, unrealized losses	166	873
Collateralized Mortgage Obligations [Member]
Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position [Line Items]
Available for sale securities in a continuous unrealized loss position, less than 12 months, fair value	14,311	116,161
Available for sale securities in a continuous unrealized loss position, less than 12 months, unrealized losses	172	3,173
Available for sale securities in a continuous unrealized loss position, 12 months or more, fair value	10,562	0
Available for sale securities in a continuous unrealized loss position, 12 months or more, unrealized losses	152	0
Available for sale securities in a continuous unrealized loss position, fair value	24,873	116,161
Available for sale securities in a continuous unrealized loss position, unrealized losses	324	3,173
Held to maturity securities in a continuous unrealized loss position, less than 12 months, fair value	24,802	68,888
Held to maturity securities in a continuous unrealized loss position, less than 12 months, unrealized losses	155	732
Held to maturity securities in a continuous unrealized loss position, 12 months or more, fair value	0	15,956
Held to maturity securities in a continuous unrealized loss position, 12 months or more, unrealized losses	0	48
Held to maturity securities in a continuous unrealized loss position, fair value	24,802	84,844
Held to maturity securities in a continuous unrealized loss position, unrealized losses	155	780
Collateralized Mortgage Backed Securities [Member]
Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position [Line Items]
Available for sale securities in a continuous unrealized loss position, less than 12 months, fair value	0	2,389
Available for sale securities in a continuous unrealized loss position, less than 12 months, unrealized losses	0	14
Available for sale securities in a continuous unrealized loss position, 12 months or more, fair value	5,338	5,502
Available for sale securities in a continuous unrealized loss position, 12 months or more, unrealized losses	22	64
Available for sale securities in a continuous unrealized loss position, fair value	5,338	7,891
Available for sale securities in a continuous unrealized loss position, unrealized losses	22	78
Held to maturity securities in a continuous unrealized loss position, less than 12 months, fair value		7,711
Held to maturity securities in a continuous unrealized loss position, less than 12 months, unrealized losses		21
Held to maturity securities in a continuous unrealized loss position, 12 months or more, fair value		0
Held to maturity securities in a continuous unrealized loss position, 12 months or more, unrealized losses		0
Held to maturity securities in a continuous unrealized loss position, fair value		7,711
Held to maturity securities in a continuous unrealized loss position, unrealized losses		21
US States and Political Subdivisions Debt Securities [Member]
Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position [Line Items]
Available for sale securities in a continuous unrealized loss position, less than 12 months, fair value	246	886
Available for sale securities in a continuous unrealized loss position, less than 12 months, unrealized losses	0	15
Available for sale securities in a continuous unrealized loss position, 12 months or more, fair value	1,298	1,814
Available for sale securities in a continuous unrealized loss position, 12 months or more, unrealized losses	9	17
Available for sale securities in a continuous unrealized loss position, fair value	1,544	2,700
Available for sale securities in a continuous unrealized loss position, unrealized losses	9	32
Corporate Debt Securities [Member]
Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position [Line Items]
Available for sale securities in a continuous unrealized loss position, less than 12 months, fair value	39,179	9,583
Available for sale securities in a continuous unrealized loss position, less than 12 months, unrealized losses	1,543	258
Available for sale securities in a continuous unrealized loss position, 12 months or more, fair value	2,934	2,952
Available for sale securities in a continuous unrealized loss position, 12 months or more, unrealized losses	61	42
Available for sale securities in a continuous unrealized loss position, fair value	42,113	12,535
Available for sale securities in a continuous unrealized loss position, unrealized losses	1,604	300
Asset-backed Securities [Member]
Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position [Line Items]
Available for sale securities in a continuous unrealized loss position, less than 12 months, fair value	16,799	17,005
Available for sale securities in a continuous unrealized loss position, less than 12 months, unrealized losses	632	626
Available for sale securities in a continuous unrealized loss position, 12 months or more, fair value	0	0
Available for sale securities in a continuous unrealized loss position, 12 months or more, unrealized losses	0	0
Available for sale securities in a continuous unrealized loss position, fair value	16,799	17,005
Available for sale securities in a continuous unrealized loss position, unrealized losses	632	626
Collateralized Debt Obligations [Member]
Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position [Line Items]
Available for sale securities in a continuous unrealized loss position, less than 12 months, fair value	0	0
Available for sale securities in a continuous unrealized loss position, less than 12 months, unrealized losses	0	0
Available for sale securities in a continuous unrealized loss position, 12 months or more, fair value	1,858	1,883
Available for sale securities in a continuous unrealized loss position, 12 months or more, unrealized losses	1,211	1,187
Available for sale securities in a continuous unrealized loss position, fair value	1,858	1,883
Available for sale securities in a continuous unrealized loss position, unrealized losses	1,211	1,187
US Government Agencies Debt Securities [Member]
Note 5 - Investment Securities (Details) - Securities in a Continuous Unrealized Loss Position [Line Items]
Held to maturity securities in a continuous unrealized loss position, less than 12 months, fair value	3,802	11,954
Held to maturity securities in a continuous unrealized loss position, less than 12 months, unrealized losses	11	72
Held to maturity securities in a continuous unrealized loss position, 12 months or more, fair value	0	0
Held to maturity securities in a continuous unrealized loss position, 12 months or more, unrealized losses	0	0
Held to maturity securities in a continuous unrealized loss position, fair value	3,802	11,954
Held to maturity securities in a continuous unrealized loss position, unrealized losses	$ 11	$ 72