Note 1 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of Significant Accounting Policies [Line Items]
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds	$ 32,573,000	$ 47,960,000	$ 29,972,000
Trading Securities	3,596,000	4,189,000
Restricted Investments	1,017,000	508,000
Other Postretirement Benefit Expense	94,000	69,000	21,000
Allocated Share-based Compensation Expense	88,000	85,000	83,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 0	$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)	$ 3.79	$ 4.38	$ 3.81
Unrecognized Tax Benefits	$ 0
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	0
New Accounting Pronouncement, Early Adoption, Effect [Member]
Summary of Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Income	171,000
Other Assets [Member]
Summary of Significant Accounting Policies [Line Items]
Other Real Estate, Foreclosed Assets, and Repossessed Assets	0	$ 0
Investment in Federal Home Loan Bank Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Restricted Investments	1,005,000
Investment in Atlantic Community Bankers Bank Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Restricted Investments	12,000
Brokerage Account [Member]
Summary of Significant Accounting Policies [Line Items]
Cash, Cash Equivalents, and Short-term Investments	1,499,000	1,349,000
US States and Political Subdivisions Debt Securities [Member]
Summary of Significant Accounting Policies [Line Items]
Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds			$ 5,000,000
Trading Securities	$ 3,596,000	$ 4,189,000