Note 3 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Note 3 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	$ 218,898	$ 81,274
Less than 12 Months - Unrealized Losses	1,399	254
12 Months or More - Fair Value	56,994	159,818
12 Months or More - Unrealized Losses	1,833	2,750
Total - Fair Value	275,892	241,092
Total - Unrealized Losses	3,232	3,004
US Government-sponsored Enterprises Debt Securities [Member]
Note 3 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	57,927	22,696
Less than 12 Months - Unrealized Losses	275	76
12 Months or More - Fair Value	21,576	60,892
12 Months or More - Unrealized Losses	263	939
Total - Fair Value	79,503	83,588
Total - Unrealized Losses	538	1,015
US States and Political Subdivisions Debt Securities [Member]
Note 3 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	30,426	20,746
Less than 12 Months - Unrealized Losses	123	81
12 Months or More - Fair Value	8,276	21,272
12 Months or More - Unrealized Losses	90	316
Total - Fair Value	38,702	42,018
Total - Unrealized Losses	213	397
Residential Mortgage Backed Securities [Member]
Note 3 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	118,978	37,451
Less than 12 Months - Unrealized Losses	851	82
12 Months or More - Fair Value	21,723	71,311
12 Months or More - Unrealized Losses	638	1,117
Total - Fair Value	140,701	108,762
Total - Unrealized Losses	1,489	1,199
Commercial Mortgage Backed Securities [Member]
Note 3 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	10,882	0
Less than 12 Months - Unrealized Losses	123	0
12 Months or More - Fair Value	0	723
12 Months or More - Unrealized Losses	0	10
Total - Fair Value	10,882	723
Total - Unrealized Losses	123	10
Corporate Debt Securities [Member]
Note 3 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	204	76
Less than 12 Months - Unrealized Losses	6	4
12 Months or More - Fair Value	5,155	5,525
12 Months or More - Unrealized Losses	794	354
Total - Fair Value	5,359	5,601
Total - Unrealized Losses	800	358
Mutual Funds and Equity Securities [Member]
Note 3 - Investment Securities (Details) - Investment Securities with Unrealized Losses Not Recognized in Income [Line Items]
Less than 12 Months - Fair Value	481	305
Less than 12 Months - Unrealized Losses	21	11
12 Months or More - Fair Value	264	95
12 Months or More - Unrealized Losses	48	14
Total - Fair Value	745	400
Total - Unrealized Losses	$ 69	$ 25