Note 4 - Investment Securities (Detail) - Investments by Contractual Maturity Date (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Due in one year or less	$ 349,899
Due in one year or less	349,940
Due in one year or less	0
Due in one year or less	0
Due after one year through five years	375,041
Due after one year through five years	370,241
Due after one year through five years	0
Due after one year through five years	0
Due after five years through ten years	194,901
Due after five years through ten years	190,047
Due after five years through ten years	62,235
Due after five years through ten years	66,523
Due after ten years (1)	370,835	[1]
Due after ten years (1)	381,252	[1]
Due after ten years (1)	711,533	[1]
Due after ten years (1)	757,383	[1]
Total	1,290,676		1,309,521
Total	1,291,480
Total	773,768
Total	$ 823,906

[1] Equity securities are reported in this category