Note 5 - Investment Securities - Investments' Gross Unrealized Losses and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Residential Mortgage Backed Securities [Member]
Available-for-Sale, Less than 12 Months, Fair Value	$ 7,855	$ 83,403
Available-for-Sale, Less than 12 Months, Unrealized Losses	(15)	(458)
Available-for-Sale, 12 Months or More, Fair Value	1,954	9,061
Available-for-Sale, 12 Months or More, Unrealized Losses	(23)	(150)
Commercial Mortgage Backed Securities [Member]
Available-for-Sale, Less than 12 Months, Fair Value	28,829	24,337
Available-for-Sale, Less than 12 Months, Unrealized Losses	(82)	(272)
Available-for-Sale, 12 Months or More, Fair Value	11,498	8,918
Available-for-Sale, 12 Months or More, Unrealized Losses	(302)	(344)
Held-to-Maturity, Less than 12 Months, Fair Value	1,948	14,143
Held-to-Maturity, Less than 12 Months, Unrealized Losses		(170)
Held-to-Maturity, 12 Months or More, Fair Value
Held-to-Maturity, 12 Months or More, Unrealized Losses
US Government Agencies Debt Securities [Member]
Available-for-Sale, Less than 12 Months, Fair Value		1,982
Available-for-Sale, Less than 12 Months, Unrealized Losses		(17)
Available-for-Sale, 12 Months or More, Fair Value
Available-for-Sale, 12 Months or More, Unrealized Losses
Held-to-Maturity, Less than 12 Months, Fair Value	1,397	11,163
Held-to-Maturity, Less than 12 Months, Unrealized Losses	(2)	(44)
Held-to-Maturity, 12 Months or More, Fair Value		1,560
Held-to-Maturity, 12 Months or More, Unrealized Losses		(27)
US Treasury Securities [Member]
Available-for-Sale, Less than 12 Months, Fair Value	80
Available-for-Sale, Less than 12 Months, Unrealized Losses
Available-for-Sale, 12 Months or More, Fair Value
Available-for-Sale, 12 Months or More, Unrealized Losses
US States and Political Subdivisions Debt Securities [Member]
Available-for-Sale, Less than 12 Months, Fair Value		707
Available-for-Sale, Less than 12 Months, Unrealized Losses		(4)
Available-for-Sale, 12 Months or More, Fair Value
Available-for-Sale, 12 Months or More, Unrealized Losses
Held-to-Maturity, Less than 12 Months, Fair Value	563	572
Held-to-Maturity, Less than 12 Months, Unrealized Losses	(3)	(4)
Held-to-Maturity, 12 Months or More, Fair Value
Held-to-Maturity, 12 Months or More, Unrealized Losses
Corporate Debt Securities [Member]
Available-for-Sale, Less than 12 Months, Fair Value		779
Available-for-Sale, Less than 12 Months, Unrealized Losses
Available-for-Sale, 12 Months or More, Fair Value
Available-for-Sale, 12 Months or More, Unrealized Losses
Available-for-Sale, Less than 12 Months, Fair Value	36,764	111,208
Available-for-Sale, Less than 12 Months, Unrealized Losses	(97)	(751)
Available-for-Sale, 12 Months or More, Fair Value	13,452	17,979
Available-for-Sale, 12 Months or More, Unrealized Losses	(325)	(494)
Held-to-Maturity, Less than 12 Months, Fair Value	3,908	25,878
Held-to-Maturity, Less than 12 Months, Unrealized Losses	(5)	(218)
Held-to-Maturity, 12 Months or More, Fair Value		1,560
Held-to-Maturity, 12 Months or More, Unrealized Losses		$ (27)