Note 5 - Securities - Summary of Securities with Gross Unrealized Losses and Fair Values (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Fair Value, Less Than 12 Months	$ 97,771	$ 147,169
Gross Unrealized Losses, Less Than 12 Months	987	3,183
Fair Value, 12 Months or Greater	15,455	15,248
Gross Unrealized Losses, 12 Months or Greater	377	645
Fair Value	113,226	162,417
Gross Unrealized Losses	1,364	3,828
US Government Agencies Debt Securities [Member]
Fair Value, Less Than 12 Months	3,005	4,535
Gross Unrealized Losses, Less Than 12 Months	29	50
Fair Value, 12 Months or Greater	0
Gross Unrealized Losses, 12 Months or Greater	0
Fair Value	3,005	4,535
Gross Unrealized Losses	29	50
Corporate Debt Securities [Member]
Fair Value, Less Than 12 Months	2,023	2,010
Gross Unrealized Losses, Less Than 12 Months	14	31
Fair Value, 12 Months or Greater	2,498	4,515
Gross Unrealized Losses, 12 Months or Greater	1	21
Fair Value	4,521	6,525
Gross Unrealized Losses	15	52
Collateralized Mortgage Backed Securities [Member]
Fair Value, Less Than 12 Months	72,199	86,091
Gross Unrealized Losses, Less Than 12 Months	789	1,974
Fair Value, 12 Months or Greater	10,899	9,885
Gross Unrealized Losses, 12 Months or Greater	216	440
Fair Value	83,098	95,976
Gross Unrealized Losses	1,005	2,414
US States and Political Subdivisions Debt Securities [Member]
Fair Value, Less Than 12 Months	20,544	54,533
Gross Unrealized Losses, Less Than 12 Months	155	1,128
Fair Value, 12 Months or Greater	1,385	207
Gross Unrealized Losses, 12 Months or Greater	13	5
Fair Value	21,929	54,740
Gross Unrealized Losses	168	1,133
Other Debt Obligations [Member]
Fair Value, Less Than 12 Months	0	0
Gross Unrealized Losses, Less Than 12 Months	0	0
Fair Value, 12 Months or Greater	673	641
Gross Unrealized Losses, 12 Months or Greater	147	179
Fair Value	673	641
Gross Unrealized Losses	$ 147	$ 179