Note 2 - Investment Securities in a Continuous Loss Position (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities in continuous loss position, less than 12 months, fair value		$ 2,863
Available-for-sale securities in continuous loss position, less than 12 months, unrealized loss		(42)
Available-for-sale securities in continuous loss position, 12 months or more, fair value	7,136	10,550
Available-for-sale securities in continuous loss position, 12 months or more, unrealized loss	(52)	(170)
Available-for-sale securities in continuous loss position, fair value	7,136	13,413
Available-for-sale securities in continuous loss position, unrealized loss	(52)	(212)
Corporate Debt Securities [Member]
Available-for-sale securities in continuous loss position, less than 12 months, fair value	2,985
Available-for-sale securities in continuous loss position, less than 12 months, unrealized loss	(15)
Available-for-sale securities in continuous loss position, 12 months or more, fair value	5,913	5,939
Available-for-sale securities in continuous loss position, 12 months or more, unrealized loss	(87)	(61)
Available-for-sale securities in continuous loss position, fair value	8,898	5,939
Available-for-sale securities in continuous loss position, unrealized loss	(102)	(61)
US Government Agencies Debt Securities [Member]
Available-for-sale securities in continuous loss position, less than 12 months, fair value		4,954
Available-for-sale securities in continuous loss position, less than 12 months, unrealized loss		(46)
Available-for-sale securities in continuous loss position, 12 months or more, fair value
Available-for-sale securities in continuous loss position, 12 months or more, unrealized loss
Available-for-sale securities in continuous loss position, fair value		4,954
Available-for-sale securities in continuous loss position, unrealized loss		(46)
Available-for-sale securities in continuous loss position, less than 12 months, fair value	2,985	7,817
Available-for-sale securities in continuous loss position, less than 12 months, unrealized loss	(15)	(88)
Available-for-sale securities in continuous loss position, 12 months or more, fair value	13,049	16,489
Available-for-sale securities in continuous loss position, 12 months or more, unrealized loss	(139)	(231)
Available-for-sale securities in continuous loss position, fair value	16,034	24,306
Available-for-sale securities in continuous loss position, unrealized loss	$ (154)	$ (319)