Note 5 - Troubled Debt Restructurings (Details)	3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Accrual [Member]
Financing Receivable, Modifications, Number of Contracts		2	2
Financing Receivable, Modifications, Recorded Investment	$ 202,000	$ 202,000	$ 205,000
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member] | Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts		6	6
Financing Receivable, Modifications, Recorded Investment	331,000	$ 331,000	$ 450,000
Real Estate Portfolio Segment [Member] | Multifamily Residential [Member]
Financing Receivable, Modifications, Number of Contracts		8	8
Financing Receivable, Modifications, Recorded Investment	533,000	$ 533,000	$ 655,000
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Accrual [Member]
Financing Receivable, Modifications, Number of Contracts		0	0
Financing Receivable, Modifications, Recorded Investment	0	$ 0	$ 0
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member] | Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts		3	3
Financing Receivable, Modifications, Recorded Investment	435,000	$ 435,000	$ 461,000
Real Estate Portfolio Segment [Member] | Nonfarm Nonresidential [Member]
Financing Receivable, Modifications, Number of Contracts		3	3
Financing Receivable, Modifications, Recorded Investment	435,000	$ 435,000	$ 461,000
Real Estate Portfolio Segment [Member] | Farmland [Member] | Accrual [Member]
Financing Receivable, Modifications, Number of Contracts		0	0
Financing Receivable, Modifications, Recorded Investment	0	$ 0	$ 0
Real Estate Portfolio Segment [Member] | Farmland [Member] | Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts		1	1
Financing Receivable, Modifications, Recorded Investment	250,000	$ 250,000	$ 250,000
Real Estate Portfolio Segment [Member] | Farmland [Member]
Financing Receivable, Modifications, Number of Contracts		1	1
Financing Receivable, Modifications, Recorded Investment	250,000	$ 250,000	$ 250,000
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Accrual [Member]
Financing Receivable, Modifications, Number of Contracts		1	1
Financing Receivable, Modifications, Recorded Investment	77,000	$ 77,000	$ 79,000
Real Estate Portfolio Segment [Member] | Construction Loans [Member] | Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts		2	2
Financing Receivable, Modifications, Recorded Investment	227,000	$ 227,000	$ 242,000
Real Estate Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Modifications, Number of Contracts		3	3
Financing Receivable, Modifications, Recorded Investment	304,000	$ 304,000	$ 321,000
Consumer Portfolio Segment [Member] | Accrual [Member]
Financing Receivable, Modifications, Number of Contracts		0	0
Financing Receivable, Modifications, Recorded Investment	0	$ 0	$ 0
Consumer Portfolio Segment [Member] | Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts		1	1
Financing Receivable, Modifications, Recorded Investment	5,000	$ 5,000	$ 5,000
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts		1	1
Financing Receivable, Modifications, Recorded Investment	$ 5,000	$ 5,000	$ 5,000
Commercial Portfolio Segment [Member] | Accrual [Member]
Financing Receivable, Modifications, Number of Contracts			0
Financing Receivable, Modifications, Recorded Investment			$ 0
Commercial Portfolio Segment [Member] | Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts			1
Financing Receivable, Modifications, Recorded Investment			$ 21,000
Commercial Portfolio Segment [Member]
Financing Receivable, Modifications, Number of Contracts	1		1
Financing Receivable, Modifications, Recorded Investment			$ 21,000
Accrual [Member]
Financing Receivable, Modifications, Number of Contracts		3	3
Financing Receivable, Modifications, Recorded Investment	$ 279,000	$ 279,000	$ 284,000
Nonaccrual [Member]
Financing Receivable, Modifications, Number of Contracts		13	14
Financing Receivable, Modifications, Recorded Investment	$ 1,248,000	$ 1,248,000	$ 1,429,000
Financing Receivable, Modifications, Number of Contracts	1	16	17
Financing Receivable, Modifications, Recorded Investment	$ 1,527,000	$ 1,527,000	$ 1,713,000