Note 3 - Investment Securities Available for Sale (Details) - The Amortized Cost And Estimated Fair Value Of Investments Available For Sale (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
U. S. Government agency securities maturing:
Amortized Cost	$ 21,158	$ 11,469
Estimated Fair Value	21,477	11,978
Five years through ten years	71,588	60,581
Five years through ten years	71,422	65,335
Amortized Cost	358,103	290,712
Estimated Fair Value	355,830	299,820
Residential Mortgage Backed Securities [Member]
U. S. Government agency securities maturing:
Amortized Cost	223,216	170,649
Estimated Fair Value	219,990	173,083
Equity Investment Other [Member]
U. S. Government agency securities maturing:
Amortized Cost	412	407
Estimated Fair Value	386	342
US Government Debt Securities [Member]
U. S. Government agency securities maturing:
One year or less	14,041	5,038
One year or less	14,198	5,053
Amortized Cost	27,688	42,568
Estimated Fair Value	$ 28,357	$ 44,029