Note 7 - Investments in Marketable Securities (Details) - Amortized Cost and Estimated Fair Value of Debt Securities as Available for Sale (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Maturities:
Within 1 year	$ 11,161	$ 9,279
Within 1 year	11,190	9,324
1 to 5 years	83,542	91,787
1 to 5 years	84,028	92,011
6 to 10 years	58,863	40,387
6 to 10 years	58,872	38,335
Over 10 years	4,076	2,431
Over 10 years	4,183	2,333
	157,642	143,884
	$ 158,273	$ 142,003