Note 5 - Securities (Details) - Securities in a Continuous Loss Position (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Temporarily Impaired Securities:
Securities in a continuous loss position, less than 12 months, fair value	$ 36,106	$ 8,636
Securities in a continuous loss position, less than 12 months, unrealized loss	272	67
Securities in a continuous loss position, 12 months or more, fair value	105,032	178,042
Securities in a continuous loss position, 12 months or more, unrealized loss	1,826	5,490
US Government Agencies Debt Securities [Member]
Temporarily Impaired Securities:
Securities in a continuous loss position, less than 12 months, fair value	25,832	6,964
Securities in a continuous loss position, less than 12 months, unrealized loss	163	30
Securities in a continuous loss position, 12 months or more, fair value	94,959	156,149
Securities in a continuous loss position, 12 months or more, unrealized loss	1,324	4,709
US States and Political Subdivisions Debt Securities [Member]
Temporarily Impaired Securities:
Securities in a continuous loss position, less than 12 months, fair value	10,274	1,222
Securities in a continuous loss position, less than 12 months, unrealized loss	109	35
Securities in a continuous loss position, 12 months or more, fair value	9,952	19,818
Securities in a continuous loss position, 12 months or more, unrealized loss	434	692
Corporate Debt Securities [Member]
Temporarily Impaired Securities:
Securities in a continuous loss position, less than 12 months, fair value		450
Securities in a continuous loss position, less than 12 months, unrealized loss		2
Securities in a continuous loss position, 12 months or more, fair value		1,948
Securities in a continuous loss position, 12 months or more, unrealized loss		27
Other Debt Obligations [Member]
Temporarily Impaired Securities:
Securities in a continuous loss position, 12 months or more, fair value	121	127
Securities in a continuous loss position, 12 months or more, unrealized loss	$ 68	$ 62