Note 6 - Investment Securities (Detail) - Schedule of Investments by Contractual Maturity Date (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Due in one year or less	$ 34,890
Due in one year or less	34,950
Due in one year or less	99,978
Due in one year or less	100,923
Due after one year through five years	225,252
Due after one year through five years	224,709
Due after one year through five years	0
Due after one year through five years	0
Due after five years through ten years	631,327
Due after five years through ten years	614,458
Due after five years through ten years	39,105
Due after five years through ten years	40,722
Due after ten years (1)	470,102
Due after ten years (1)	479,625
Due after ten years (1)	945,625
Due after ten years (1)	989,879
Total	1,361,571	1,309,521
Total	1,353,742
Total	1,084,708
Total	$ 1,131,524