Note 3 - Investment Securities Available for Sale (Detail) - The Amortized Cost And Estimated Fair Value Of Investments Available For Sale (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
U. S. Government agency securities maturing:
Amortized Cost	$ 12,876	$ 10,089
Estimated Fair Value	13,545	10,539
Amortized Cost	59,879	47,459
Estimated Fair Value	64,826	51,234
Amortized Cost	286,319	305,686
Estimated Fair Value	296,363	313,811
Residential Mortgage Backed Securities [Member]
U. S. Government agency securities maturing:
Amortized Cost	168,439	145,451
Estimated Fair Value	171,374	147,978
Equity Investment Other [Member]
U. S. Government agency securities maturing:
Amortized Cost	407	404
Estimated Fair Value	355	307
US Government Debt Securities [Member]
U. S. Government agency securities maturing:
One year or less		15,783
One year or less		15,906
Amortized Cost	41,840	83,638
Estimated Fair Value	43,071	84,740
Amortized Cost	2,878	2,862
Estimated Fair Value	$ 3,192	$ 3,107