Note 3 - Investment Securities (Detail) - Amortized cost and estimated fair value by maturity of securities: (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
One year or less	$ 27,871
One year or less	27,975
One year or less	2,008
One year or less	2,009
After one through five years	229,312
After one through five years	229,683
After one through five years	74,190
After one through five years	74,310
After five through ten years	168,736
After five through ten years	170,037
After five through ten years	82,035
After five through ten years	81,940
After ten years	70,222
After ten years	72,883
After ten years	17,900
After ten years	17,844
Other securities	14,787
Other securities	15,239
Total	496,141
Total	500,578
Total	190,920
Total	$ 191,342