Note 8 - Long-term Borrowings - Junior Subordinated Debt Outstanding Payables (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Apr. 07, 2006
Principal amount			$ 20,600
Junior Subordinated Debt [Member]
Principal amount	$ 28,257	$ 28,232
Junior Subordinated Debt [Member] | AMNB Statutory Trust I [Member]
Principal amount	20,619	20,619
Junior Subordinated Debt [Member] | MidCarolina Trust I [Member]
Principal amount	4,559	4,545
Junior Subordinated Debt [Member] | MidCarolina Trust II [Member]
Principal amount	$ 3,079	$ 3,068
London Interbank Offered Rate (LIBOR) [Member]
Interest rate	1.35%
London Interbank Offered Rate (LIBOR) [Member] | Junior Subordinated Debt [Member] | MidCarolina Trust I [Member]
Interest rate	3.45%
London Interbank Offered Rate (LIBOR) [Member] | Junior Subordinated Debt [Member] | MidCarolina Trust II [Member]
Interest rate	2.95%