Note 9 - Financial Assets Measured at Fair Value on a Recurring and Nonrecurring Basis (Details) - USD ($)		Jun. 30, 2016	Dec. 31, 2015
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Trading securities
Investment securities available-for-sale
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Trading securities		3,459,000	4,189,000
Investment securities available-for-sale		73,888,000	78,954,000
US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Trading securities
Investment securities available-for-sale
US States and Political Subdivisions Debt Securities [Member]
Trading securities		3,459,000	4,189,000
Investment securities available-for-sale		73,888,000	78,954,000
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale		60,510,000	61,779,000
US Government Agencies Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale
US Government Agencies Debt Securities [Member]
Investment securities available-for-sale		60,510,000	61,779,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale		129,027,000	136,681,000
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Investment securities available-for-sale		129,027,000	136,681,000
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale		62,545,000	65,610,000
Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale
Collateralized Mortgage Obligations [Member]
Investment securities available-for-sale		62,545,000	65,610,000
Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale
Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale		2,400,000	2,653,000
Collateralized Debt Obligations [Member]
Investment securities available-for-sale		2,400,000	2,653,000
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale		8,110,000	9,004,000
Corporate Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale
Corporate Debt Securities [Member]
Investment securities available-for-sale		8,110,000	9,004,000
Equity Securities [Member] | Fair Value, Inputs, Level 1 [Member]
Investment securities available-for-sale		7,773,000	7,234,000
Equity Securities [Member] | Fair Value, Inputs, Level 2 [Member]
Investment securities available-for-sale
Equity Securities [Member] | Fair Value, Inputs, Level 3 [Member]
Investment securities available-for-sale
Equity Securities [Member]
Investment securities available-for-sale		7,773,000	7,234,000
Fair Value, Inputs, Level 1 [Member] | Impaired Loans [Member]
Nonrecurring fair value measurements	[1]
Fair Value, Inputs, Level 1 [Member] | Mortgage Servicing Rights [Member]
Nonrecurring fair value measurements	[1]
Fair Value, Inputs, Level 1 [Member]
Trading securities
Investment securities available-for-sale		7,773,000	7,234,000
Recurring fair value measurements		7,773,000	7,234,000
Nonrecurring fair value measurements	[1]
Fair Value, Inputs, Level 2 [Member] | Impaired Loans [Member]
Nonrecurring fair value measurements	[1]
Fair Value, Inputs, Level 2 [Member] | Mortgage Servicing Rights [Member]
Nonrecurring fair value measurements	[1]
Fair Value, Inputs, Level 2 [Member]
Trading securities		3,459,000	4,189,000
Investment securities available-for-sale		334,080,000	352,028,000
Recurring fair value measurements		337,539,000	356,217,000
Nonrecurring fair value measurements	[1]
Fair Value, Inputs, Level 3 [Member] | Impaired Loans [Member]
Nonrecurring fair value measurements	[1]	1,962,000	1,698,000
Fair Value, Inputs, Level 3 [Member] | Mortgage Servicing Rights [Member]
Nonrecurring fair value measurements	[1]	45,000	133,000
Fair Value, Inputs, Level 3 [Member]
Trading securities
Investment securities available-for-sale		2,400,000	2,653,000
Recurring fair value measurements		2,400,000	2,653,000
Nonrecurring fair value measurements	[1]	2,007,000	1,831,000
Impaired Loans [Member]
Nonrecurring fair value measurements	[1]	1,962,000	1,698,000
Mortgage Servicing Rights [Member]
Nonrecurring fair value measurements	[1]	45,000	133,000
Trading securities		3,459,000	4,189,000
Investment securities available-for-sale		344,253,000	361,915,000
Recurring fair value measurements		347,712,000	366,104,000
Nonrecurring fair value measurements	[1]	$ 2,007,000	$ 1,831,000

[1] impairment