Note 6 - Investment Securities (Detail) - The Amortized Cost And Estimated Fair Value Of The Securities Portfolio By Contractual Maturity (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Total	$ 875	$ 875
Available For Sale Amortized Cost [Member]
Due in one year or less	3,143
Due after one year through five years	58,570
Due after five years through ten years	99,166
Due after ten years	20,461
Mortgage-backed securities	400,240
Total	581,580
Available For Sale Estimated Fair Value [Member]
Due in one year or less	3,145
Due after one year through five years	59,380
Due after five years through ten years	103,288
Due after ten years	19,946
Mortgage-backed securities	414,185
Total	599,944
Held To Maturity Amortized Cost [Member]
Due after ten years	875
Total	875
Held To Maturity Estimated Fair Value [Member]
Due after ten years	1,008
Total	$ 1,008