Note 6 - Investment Securities (Detail) - Investments by Contractual Maturity Date (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Due in one year or less	$ 157,806
Due in one year or less	157,804
Due in one year or less	0
Due in one year or less	0
Due after one year through five years	385,083
Due after one year through five years	378,412
Due after one year through five years	0
Due after one year through five years	0
Due after five years through ten years	241,904
Due after five years through ten years	233,331
Due after five years through ten years	57,554
Due after five years through ten years	61,206
Due after ten years (1)	505,419	[1]
Due after ten years (1)	524,024	[1]
Due after ten years (1)	791,822	[1]
Due after ten years (1)	846,861	[1]
Total	1,290,212		1,309,521
Total	1,293,571
Total	849,376
Total	$ 908,067

[1] Equity securities are reported in this category