Note 4 - Securities (Details) - Securities With Unrealized Losses - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Note 4 - Securities (Details) - Securities With Unrealized Losses [Line Items]
Less than 12 months, fair value	$ 165,097	$ 53,672
Less than 12 months, unrealized losses	1,193	174
12 months or more, fair value	40,360	82,470
12 months or more, unrealized losses	1,276	1,875
Fair value	205,457	136,142
Unrealized losses	2,469	2,049
US Government-sponsored Enterprises Debt Securities [Member]
Note 4 - Securities (Details) - Securities With Unrealized Losses [Line Items]
Less than 12 months, fair value	102,098	36,979
Less than 12 months, unrealized losses	500	30
12 months or more, fair value	8,469	26,848
12 months or more, unrealized losses	265	532
Fair value	110,567	63,827
Unrealized losses	765	562
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Note 4 - Securities (Details) - Securities With Unrealized Losses [Line Items]
Less than 12 months, fair value	49,774	4,038
Less than 12 months, unrealized losses	662	77
12 months or more, fair value	29,936	49,325
12 months or more, unrealized losses	992	1,268
Fair value	79,710	53,363
Unrealized losses	1,654	1,345
US States and Political Subdivisions Debt Securities [Member]
Note 4 - Securities (Details) - Securities With Unrealized Losses [Line Items]
Less than 12 months, fair value	13,225	12,655
Less than 12 months, unrealized losses	31	67
12 months or more, fair value	1,955	6,297
12 months or more, unrealized losses	19	75
Fair value	15,180	18,952
Unrealized losses	$ 50	$ 142