Note 3 - Investment Securities (Details) - Income Earned on Securities - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Non-taxable:
Total	$ 8,050	$ 4,766	$ 13,929	$ 9,315
Held-to-maturity Securities [Member]
Taxable:
Taxable	1,307	1,378	2,696	2,727
Non-taxable:
Non taxable	2,732	2,633	5,334	5,252
Available-for-sale Securities [Member]
Taxable:
Taxable	3,172	729	4,755	1,279
Non-taxable:
Non taxable	$ 839	$ 26	$ 1,144	$ 57