Note 4 - Investment Securities (Details) - Investments by Contractual Maturity Date (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Investments by Contractual Maturity Date [Abstract]
Due in one year or less	$ 115,033
Due in one year or less	115,068
Due after one year through five years	569,853
Due after one year through five years	570,371
Due after five years through ten years	85,654
Due after five years through ten years	85,097
Due after ten years (1)	553,868	[1]
Due after ten years (1)	548,399	[1]
Total	1,324,408		1,637,965
Total	$ 1,318,935		$ 1,586,668

[1] Equity securities are reported in this category