Note 4 - Securities - Securities Available-for-Sale with Unrealized Losses (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Less than 12 Months - Fair Value	$ 1,067	$ 42,112
Less than 12 Months - Unrealized Loss	(5)	(407)
12 Months or More - Fair Value		3,645
12 Months or More - Unrealized Loss		(66)
Fair Value	1,067	45,757
Unrealized Loss	(5)	(473)
US Government-sponsored Enterprises Debt Securities [Member]
Less than 12 Months - Fair Value		7,964
Less than 12 Months - Unrealized Loss		(46)
12 Months or More - Fair Value
12 Months or More - Unrealized Loss
Fair Value		7,964
Unrealized Loss		(46)
Less than 12 Months - Fair Value	1,067	50,076
Less than 12 Months - Unrealized Loss	(5)	(453)
12 Months or More - Fair Value		3,645
12 Months or More - Unrealized Loss		(66)
Fair Value	1,067	53,721
Unrealized Loss	$ (5)	$ (519)