Note 2 - Investment Securities - Municipal Securities Portfolio (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Investment securities available for sale, amortized cost	$ 190,369,000	$ 243,948,000
Investment securities available for sale, at fair value	192,606,119	248,294,725
Municipal Revenue Bonds - University and College [Member]
Investment securities available for sale, amortized cost	8,588,000
Investment securities available for sale, at fair value	8,635,000
Municipal Revenue Bonds - Public Improvements [Member]
Investment securities available for sale, amortized cost	6,125,000
Investment securities available for sale, at fair value	6,144,000
Municipal General Obligation Bonds [Member]
Investment securities available for sale, amortized cost	30,891,000
Investment securities available for sale, at fair value	30,956,000
Municipal General Obligation Bonds [Member] | State of Pennsylvania [Member]
Investment securities available for sale, amortized cost	3,874,000
Investment securities available for sale, at fair value	3,897,000
Municipal General Obligation Bonds [Member] | State of California [Member]
Investment securities available for sale, amortized cost	3,679,000
Investment securities available for sale, at fair value	3,709,000
Municipal General Obligation Bonds [Member] | WASHINGTON
Investment securities available for sale, amortized cost	3,384,000
Investment securities available for sale, at fair value	3,305,000
Municipal General Obligation Bonds [Member] | State of Indiana [Member]
Investment securities available for sale, amortized cost	2,412,000
Investment securities available for sale, at fair value	2,413,000
Municipal General Obligation Bonds [Member] | TEXAS
Investment securities available for sale, amortized cost	2,276,000
Investment securities available for sale, at fair value	2,210,000
Municipal General Obligation Bonds [Member] | FLORIDA
Investment securities available for sale, amortized cost	2,234,000
Investment securities available for sale, at fair value	2,223,000
Municipal General Obligation Bonds [Member] | State of Alabama [Member]
Investment securities available for sale, amortized cost	1,821,000
Investment securities available for sale, at fair value	1,803,000
Municipal General Obligation Bonds [Member] | State of Utah [Member]
Investment securities available for sale, amortized cost	1,791,000
Investment securities available for sale, at fair value	1,747,000
Municipal General Obligation Bonds [Member] | State of Nevada [Member]
Investment securities available for sale, amortized cost	1,339,000
Investment securities available for sale, at fair value	1,366,000
Municipal General Obligation Bonds [Member] | Other States [Member]
Investment securities available for sale, amortized cost	8,081,000
Investment securities available for sale, at fair value	8,283,000
Municipal General Obligation Bonds [Member] | State of North Carolina [Member]
Investment securities available for sale, amortized cost	4,239,000
Investment securities available for sale, at fair value	4,314,000
Municipal Revenue Bonds - Pension Funding [Member]
Investment securities available for sale, amortized cost	1,901,000
Investment securities available for sale, at fair value	1,954,000
Municipal Revenue Bonds - Refunding Bonds [Member]
Investment securities available for sale, amortized cost	1,631,000
Investment securities available for sale, at fair value	1,601,000
Municipal Revenue Bonds - Other [Member]
Investment securities available for sale, amortized cost	4,329,000
Investment securities available for sale, at fair value	4,392,000
Municipal Revenue Bonds [Member]
Investment securities available for sale, amortized cost	22,574,000
Investment securities available for sale, at fair value	22,726,000
Municipal Revenue Bonds [Member] | State of Pennsylvania [Member]
Investment securities available for sale, amortized cost	1,901,000
Investment securities available for sale, at fair value	1,954,000
Municipal Revenue Bonds [Member] | Other States [Member]
Investment securities available for sale, amortized cost	4,663,000
Investment securities available for sale, at fair value	4,630,000
Municipal Revenue Bonds [Member] | State of New York [Member]
Investment securities available for sale, amortized cost	7,200,000
Investment securities available for sale, at fair value	7,224,000
Municipal Revenue Bonds [Member] | State of Mississippi [Member]
Investment securities available for sale, amortized cost	2,319,000
Investment securities available for sale, at fair value	2,319,000
Municipal Revenue Bonds [Member] | State of Oklahoma [Member]
Investment securities available for sale, amortized cost	2,252,000
Investment securities available for sale, at fair value	2,285,000
US States and Political Subdivisions Debt Securities [Member]
Investment securities available for sale, amortized cost	53,465,000	55,534,000
Investment securities available for sale, at fair value	$ 53,682,000	$ 56,831,000