Note 8 - Fair Value Measurements - Assets Measured at Fair Value on Recurring and Nonrecurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Securities available for sale	$ 313,540	$ 283,502
Equity securities	1,800	1,600
Fair Value, Recurring [Member]
Securities available for sale	313,540	283,502
Equity securities	1,787	1,553
Fair Value, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available for sale	69,020	61,359
Fair Value, Recurring [Member] | Agency Collateralized Mortgage Obligations [Member]
Securities available for sale	14,601	21,030
Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member]
Securities available for sale	98,433	81,531
Fair Value, Recurring [Member] | Municipal Notes [Member]
Securities available for sale	131,486	119,582
Fair Value, Nonrecurring [Member]
Impaired loans	3,286	3,168
Loans held for sale	4,331	7,941
Fair Value, Nonrecurring [Member] | Residential Mortgage Segment [Member]
Impaired loans	1,879	1,728
Fair Value, Nonrecurring [Member] | Land Segment [Member]
Impaired loans	100	97
Fair Value, Nonrecurring [Member] | Commercial Real Estate Segment [Member]
Impaired loans	760	779
Fair Value, Nonrecurring [Member] | Commercial Business Segment [Member]
Impaired loans	201	211
Fair Value, Nonrecurring [Member] | Home Equity and Second Mortgage [Member]
Impaired loans	346	353
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Securities available for sale	0	0
Equity securities	1,787	1,553
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available for sale	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Agency Collateralized Mortgage Obligations [Member]
Securities available for sale	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member]
Securities available for sale	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Municipal Notes [Member]
Securities available for sale	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Nonrecurring [Member]
Impaired loans	0	0
Loans held for sale	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Nonrecurring [Member] | Residential Mortgage Segment [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Nonrecurring [Member] | Land Segment [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Nonrecurring [Member] | Commercial Real Estate Segment [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Nonrecurring [Member] | Commercial Business Segment [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Nonrecurring [Member] | Home Equity and Second Mortgage [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Securities available for sale	313,540	283,502
Equity securities	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available for sale	69,020	61,359
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Agency Collateralized Mortgage Obligations [Member]
Securities available for sale	14,601	21,030
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member]
Securities available for sale	98,433	81,531
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Municipal Notes [Member]
Securities available for sale	131,486	119,582
Fair Value, Inputs, Level 2 [Member] | Fair Value, Nonrecurring [Member]
Impaired loans	0	0
Loans held for sale	4,331	7,941
Fair Value, Inputs, Level 2 [Member] | Fair Value, Nonrecurring [Member] | Residential Mortgage Segment [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Nonrecurring [Member] | Land Segment [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Nonrecurring [Member] | Commercial Real Estate Segment [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Nonrecurring [Member] | Commercial Business Segment [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Nonrecurring [Member] | Home Equity and Second Mortgage [Member]
Impaired loans	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Securities available for sale	0	0
Equity securities	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Securities available for sale	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Agency Collateralized Mortgage Obligations [Member]
Securities available for sale	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | US Government Agencies Debt Securities [Member]
Securities available for sale	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Municipal Notes [Member]
Securities available for sale	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member]
Impaired loans	3,286	3,168
Loans held for sale	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Residential Mortgage Segment [Member]
Impaired loans	1,879	1,728
Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Land Segment [Member]
Impaired loans	100	97
Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Commercial Real Estate Segment [Member]
Impaired loans	760	779
Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Commercial Business Segment [Member]
Impaired loans	201	211
Fair Value, Inputs, Level 3 [Member] | Fair Value, Nonrecurring [Member] | Home Equity and Second Mortgage [Member]
Impaired loans	$ 346	$ 353