Note 6 - Investment Securities (Details) - Investments by Contractual Maturity Date (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013
Investments by Contractual Maturity Date [Abstract]
Due in one year or less	$ 385,848
Due in one year or less	385,941
Due after one year through five years	178,382
Due after one year through five years	179,513
Due after five years through ten years	100,805
Due after five years through ten years	98,143
Due after ten years (1)	951,979	[1]
Due after ten years (1)	915,300	[1]
Total	1,617,014		1,637,965
Total	$ 1,578,897		$ 1,586,668

[1] Equity securities are reported in this category