Note 6 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Note 6 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	$ 48,834	$ 218,898
Less than 12 Months - Unrealized Losses	134	1,399
12 Months or More - Fair Value	47,455	56,994
12 Months or More - Unrealized Losses	1,607	1,833
Total - Fair Value	96,289	275,892
Total - Unrealized Losses	1,741	3,232
US Government-sponsored Enterprises Debt Securities [Member]
Note 6 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	19,509	57,927
Less than 12 Months - Unrealized Losses	6	275
12 Months or More - Fair Value	9,992	21,576
12 Months or More - Unrealized Losses	5	263
Total - Fair Value	29,501	79,503
Total - Unrealized Losses	11	538
US States and Political Subdivisions Debt Securities [Member]
Note 6 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	20,199	30,426
Less than 12 Months - Unrealized Losses	106	123
12 Months or More - Fair Value	5,338	8,276
12 Months or More - Unrealized Losses	11	90
Total - Fair Value	25,537	38,702
Total - Unrealized Losses	117	213
Residential Mortgage Backed Securities [Member]
Note 6 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	5,814	118,978
Less than 12 Months - Unrealized Losses	5	851
12 Months or More - Fair Value	27,245	21,723
12 Months or More - Unrealized Losses	203	638
Total - Fair Value	33,059	140,701
Total - Unrealized Losses	208	1,489
Commercial Mortgage Backed Securities [Member]
Note 6 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	2,567	10,882
Less than 12 Months - Unrealized Losses	6	123
12 Months or More - Fair Value	0	0
12 Months or More - Unrealized Losses	0	0
Total - Fair Value	2,567	10,882
Total - Unrealized Losses	6	123
Corporate Debt Securities [Member]
Note 6 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	150	204
Less than 12 Months - Unrealized Losses	1	6
12 Months or More - Fair Value	4,605	5,155
12 Months or More - Unrealized Losses	1,351	794
Total - Fair Value	4,755	5,359
Total - Unrealized Losses	1,352	800
Mutual Funds and Equity Securities [Member]
Note 6 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	595	481
Less than 12 Months - Unrealized Losses	10	21
12 Months or More - Fair Value	275	264
12 Months or More - Unrealized Losses	37	48
Total - Fair Value	870	745
Total - Unrealized Losses	$ 47	$ 69