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	Jun. 30, 2012	Dec. 31, 2011
Total	$ 875	$ 875
Available For Sale Amortized Cost [Member]
Due in one year or less	11,273
Due after one year through five years	73,957
Due after five years through ten years	76,922
Due after ten years	20,760
Mortgage-backed securities	417,447
Total	600,359
Available For Sale Estimated Fair Value [Member]
Due in one year or less	11,262
Due after one year through five years	74,672
Due after five years through ten years	80,197
Due after ten years	19,897
Mortgage-backed securities	429,374
Total	615,402
Held To Maturity Amortized Cost [Member]
Due after ten years	875
Total	875
Held To Maturity Estimated Fair Value [Member]
Due after ten years	997
Total	$ 997