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	Jun. 30, 2013	Dec. 31, 2012
U. S. Government agency securities maturing:
Amortized Cost	$ 16,642	$ 11,469
Estimated Fair Value	16,964	11,978
Five years through ten years	70,340	60,581
Five years through ten years	70,505	65,335
Amortized Cost	337,291	290,712
Estimated Fair Value	335,779	299,820
Residential Mortgage Backed Securities [Member]
U. S. Government agency securities maturing:
Amortized Cost	211,079	170,649
Estimated Fair Value	208,439	173,083
Equity Investment Other [Member]
U. S. Government agency securities maturing:
Amortized Cost	412	407
Estimated Fair Value	373	342
US Government Debt Securities [Member]
U. S. Government agency securities maturing:
One year or less	9,035	5,038
One year or less	9,059	5,053
Amortized Cost	29,783	42,568
Estimated Fair Value	$ 30,439	$ 44,029