Note 4 - Loans and Allowance for Loan Losses (Details) - Impaired Loans, Net of Government Guarantees and Excluding Loans Acquired, Segregated by Class of Loans - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Consumer:
Unpaid contractual principal balance	$ 20,862,000		$ 20,862,000		$ 16,326,000
Recorded investment with no allowance	12,923,000		12,923,000		14,247,000
Recorded investment with allowance	4,321,000		4,321,000		422,000
Total recorded investment	17,244,000		17,244,000		14,669,000
Related allowance	2,797,000		2,797,000		2,075,000
Average investment in impaired loans	17,080,000	$ 17,749,000	16,296,000	$ 18,186,000
Interest income recognized	350,000	200,000	900,000	564,000
Consumer Portfolio Segment [Member]
Consumer:
Unpaid contractual principal balance	1,162,000		1,162,000		801,000
Recorded investment with no allowance	1,113,000		1,113,000		807,000
Recorded investment with allowance	20,000		20,000		9,000
Total recorded investment	1,133,000		1,133,000		816,000
Related allowance	131,000		131,000		124,000
Average investment in impaired loans	1,062,000	1,252,000	986,000	1,303,000
Interest income recognized	21,000	14,000	53,000	39,000
Consumer Portfolio Segment [Member] | Credit Card Receivable [Member]
Consumer:
Unpaid contractual principal balance	461,000		461,000		197,000
Recorded investment with no allowance	461,000		461,000		197,000
Total recorded investment	461,000		461,000		197,000
Related allowance	7,000		7,000		6,000
Average investment in impaired loans	450,000	471,000	394,000	482,000
Interest income recognized	8,000		20,000	9,000
Consumer Portfolio Segment [Member] | Other Loans [Member]
Consumer:
Unpaid contractual principal balance	701,000		701,000		604,000
Recorded investment with no allowance	652,000		652,000		610,000
Recorded investment with allowance	20,000		20,000		9,000
Total recorded investment	672,000		672,000		619,000
Related allowance	124,000		124,000		118,000
Average investment in impaired loans	612,000	781,000	592,000	821,000
Interest income recognized	13,000	14,000	33,000	30,000
Commercial Real Estate Portfolio Segment [Member]
Consumer:
Unpaid contractual principal balance	16,610,000		16,610,000		13,797,000
Recorded investment with no allowance	10,447,000		10,447,000		12,414,000
Recorded investment with allowance	3,428,000		3,428,000		413,000
Total recorded investment	13,875,000		13,875,000		12,827,000
Related allowance	2,040,000		2,040,000		1,766,000
Average investment in impaired loans	14,350,000	15,569,000	13,385,000	16,059,000
Interest income recognized	285,000	176,000	741,000	499,000
Commercial Real Estate Portfolio Segment [Member] | Other Loans [Member]
Consumer:
Unpaid contractual principal balance	4,859,000		4,859,000		1,955,000
Recorded investment with no allowance	3,541,000		3,541,000		1,446,000
Recorded investment with allowance	90,000		90,000		36,000
Total recorded investment	3,631,000		3,631,000		1,482,000
Related allowance	699,000		699,000		268,000
Average investment in impaired loans	3,175,000	6,663,000	2,830,000	8,115,000
Interest income recognized	68,000	75,000	157,000	252,000
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Consumer:
Unpaid contractual principal balance	5,683,000		5,683,000		7,400,000
Recorded investment with no allowance	2,196,000		2,196,000		7,020,000
Recorded investment with allowance	2,781,000		2,781,000
Total recorded investment	4,977,000		4,977,000		7,020,000
Related allowance	378,000		378,000		599,000
Average investment in impaired loans	6,230,000	4,323,000	5,532,000	3,662,000
Interest income recognized	109,000	49,000	306,000	114,000
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Loans [Member]
Consumer:
Unpaid contractual principal balance	6,068,000		6,068,000		4,442,000
Recorded investment with no allowance	4,710,000		4,710,000		3,948,000
Recorded investment with allowance	557,000		557,000		377,000
Total recorded investment	5,267,000		5,267,000		4,325,000
Related allowance	963,000		963,000		899,000
Average investment in impaired loans	4,945,000	4,583,000	5,023,000	4,282,000
Interest income recognized	108,000	52,000	278,000	133,000
Commercial Portfolio Segment [Member]
Consumer:
Unpaid contractual principal balance	3,090,000		3,090,000		1,728,000
Recorded investment with no allowance	1,363,000		1,363,000		1,026,000
Recorded investment with allowance	873,000		873,000
Total recorded investment	2,236,000		2,236,000		1,026,000
Related allowance	626,000		626,000		185,000
Average investment in impaired loans	1,668,000	928,000	1,925,000	824,000
Interest income recognized	44,000	10,000	107,000	26,000
Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Consumer:
Unpaid contractual principal balance	2,883,000		2,883,000		1,227,000
Recorded investment with no allowance	1,145,000		1,145,000		566,000
Recorded investment with allowance	873,000		873,000
Total recorded investment	2,018,000		2,018,000		566,000
Related allowance	588,000		588,000		102,000
Average investment in impaired loans	1,488,000	654,000	1,673,000	646,000
Interest income recognized	39,000	7,000	93,000	20,000
Commercial Portfolio Segment [Member] | Agricultural Loans [Member]
Consumer:
Unpaid contractual principal balance	207,000		207,000		501,000
Recorded investment with no allowance	218,000		218,000		460,000
Total recorded investment	218,000		218,000		466,000
Related allowance	38,000		38,000		$ 83,000
Average investment in impaired loans	180,000	274,000	252,000	178,000
Interest income recognized	$ 5,000	$ 3,000	$ 14,000	$ 6,000