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		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	$ 19,105,000		$ 19,105,000		$ 16,326,000
Recorded investment with no allowance	14,468,000		14,468,000		14,247,000
Recorded investment with allowance	1,889,000		1,889,000		422,000
Total recorded investment	16,357,000		16,357,000		14,669,000
Related allowance	2,012,000		2,012,000		2,075,000
Average investment in impaired loans	16,638,000	$ 18,743,000	15,981,000	$ 18,601,000
Interest income recognized	300,000	158,000	549,000	364,000
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	998,000		998,000		801,000
Recorded investment with no allowance	981,000		981,000		807,000
Recorded investment with allowance	21,000		21,000		9,000
Total recorded investment	1,002,000		1,002,000		816,000
Related allowance	103,000		103,000		124,000
Average investment in impaired loans	997,000	1,224,000	937,000	1,293,000
Interest income recognized	18,000	11,000	31,000	25,000
Consumer Portfolio Segment [Member] | Credit Card Receivable [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	479,000		479,000		197,000
Recorded investment with no allowance	479,000		479,000		197,000
Total recorded investment	479,000		479,000		197,000
Related allowance	14,000		14,000		6,000
Average investment in impaired loans	459,000	446,000	372,000	470,000
Interest income recognized	7,000	4,000	12,000	9,000
Consumer Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	519,000		519,000		604,000
Recorded investment with no allowance	502,000		502,000		610,000
Recorded investment with allowance	21,000		21,000		9,000
Total recorded investment	523,000		523,000		619,000
Related allowance	89,000		89,000		118,000
Average investment in impaired loans	538,000	778,000	565,000	823,000
Interest income recognized	11,000	7,000	19,000	16,000
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	16,088,000		16,088,000		13,797,000
Recorded investment with no allowance	11,249,000		11,249,000		12,414,000
Recorded investment with allowance	766,000		766,000		413,000
Total recorded investment	12,015,000		12,015,000		12,827,000
Related allowance	1,513,000		1,513,000		1,766,000
Average investment in impaired loans	13,421,000	16,656,000	13,222,000	16,552,000
Interest income recognized	248,000	140,000	455,000	324,000
Commercial Real Estate Portfolio Segment [Member] | Other Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	4,240,000		4,240,000		1,955,000
Recorded investment with no allowance	3,362,000		3,362,000		1,446,000
Recorded investment with allowance	127,000		127,000		36,000
Total recorded investment	3,489,000		3,489,000		1,482,000
Related allowance	593,000		593,000		268,000
Average investment in impaired loans	3,104,000	9,562,000	2,563,000	9,437,000
Interest income recognized	48,000	80,000	88,000	185,000
Commercial Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	6,104,000		6,104,000		7,400,000
Recorded investment with no allowance	2,650,000		2,650,000		7,020,000
Total recorded investment	2,650,000		2,650,000		7,020,000
Related allowance					599,000
Average investment in impaired loans	5,066,000	2,840,000	5,717,000	2,962,000
Interest income recognized	107,000	24,000	197,000	58,000
Commercial Real Estate Portfolio Segment [Member] | Single Family Residential Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	5,744,000		5,744,000		4,442,000
Recorded investment with no allowance	5,237,000		5,237,000		3,948,000
Recorded investment with allowance	639,000		639,000		377,000
Total recorded investment	5,876,000		5,876,000		4,325,000
Related allowance	920,000		920,000		899,000
Average investment in impaired loans	5,251,000	4,254,000	4,942,000	4,153,000
Interest income recognized	93,000	36,000	170,000	81,000
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	2,019,000		2,019,000		1,728,000
Recorded investment with no allowance	2,238,000		2,238,000		1,026,000
Recorded investment with allowance	1,102,000		1,102,000
Total recorded investment	33,407,000		33,407,000		1,026,000
Related allowance	396,000		396,000		185,000
Average investment in impaired loans	2,220,000	863,000	1,822,000	756,000
Interest income recognized	34,000	7,000	63,000	15,000
Commercial Portfolio Segment [Member] | Commercial Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	1,824,000		1,824,000		1,227,000
Recorded investment with no allowance	2,048,000		2,048,000		566,000
Recorded investment with allowance	1,102,000		1,102,000
Total recorded investment	3,150,000		3,150,000		566,000
Related allowance	363,000		363,000		102,000
Average investment in impaired loans	2,054,000	765,000	1,558,000	664,000
Interest income recognized	29,000	6,000	54,000	13,000
Commercial Portfolio Segment [Member] | Agricultural Loans [Member]
Financing Receivable, Impaired [Line Items]
Unpaid contractual principal	195,000		195,000		501,000
Recorded investment with no allowance	190,000		190,000		460,000
Total recorded investment	190,000		190,000		466,000
Related allowance	33,000		33,000		$ 83,000
Average investment in impaired loans	166,000	98,000	264,000	92,000
Interest income recognized	$ 5,000	$ 1,000	$ 9,000	$ 2,000