Note 4 - Revenue Recognition From Contracts With Customers - Sources of Non-interest Income (Details) - USD ($)		3 Months Ended			9 Months Ended
		Sep. 30, 2018		Sep. 30, 2017	Sep. 30, 2018		Sep. 30, 2017
Net Gains on Sales of Loans		$ 52,000	[1]	$ 137,000	$ 106,000	[1]	$ 389,000
Net gains on sales of investments			[1]	10,000		[1]	132,000
Fair Value of Equity Securities		35,000	[1]		54,000	[1]
Net Gains on Purchased Tax Credits		11,000	[1]	14,000	33,000	[1]	43,000
Net Loss on Disposal of Fixed Assets		(74,000)	[1]		(74,000)	[1]
Income from Bank-Owned Life Insurance		135,000	[1]	116,000	370,000	[1]	348,000
Other		16,000	[1]	28,000	80,000	[1]	87,000
Total		2,088,000		1,818,000	6,299,000		5,860,000
Total non-interest expense		9,365,000		5,897,000	25,526,000		18,418,000
Net non-interest income		2,039,000			6,262,000
Accounting Standards Update 2014-09 [Member]
Other		16,000			80,000
Total		1,929,000			5,810,000
Other Real Estate Owned Expense		49,000			37,000
Total non-interest expense		49,000			37,000
Deposit Account [Member]
Noninterest income		866,000		630,000	2,176,000		1,839,000
Deposit Account [Member] | Accounting Standards Update 2014-09 [Member]
Noninterest income	[2]	866,000			2,176,000
Insurance Commissions [Member]
Noninterest income		920,000		758,000	2,731,000		2,686,000
Insurance Commissions [Member] | Accounting Standards Update 2014-09 [Member]
Noninterest income		920,000			2,731,000
Financial Service, Other [Member]
Noninterest income		127,000		$ 125,000	823,000		$ 336,000
Financial Service, Other [Member] | Accounting Standards Update 2014-09 [Member]
Noninterest income	[3]	$ 127,000			$ 823,000

[1] Not within the scope of ASC 606.

[2] Interchange fees and ATM fees are included within this line item.

[3] The Other Commissions category includes wealth management referral fees, check sales and safety deposit box rentals totaling $127,000 and $336,000 for the three and nine months ended September 30, 2018, which is in the scope of ASC 606; the remaining balance of $487,000 for the nine months ended September 30, 2018, mainly represents income derived from an assumable rate conversion ("ARC") loan referral fee and a bank-owned life insurance policy claim for the nine months ended September 30, 2018, which are outside the scope of ASC 606.