Regulatory Capital (Details) - AuburnBank [Member] $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Tier One Leverage Capital [Abstract]
Tier One Leverage Capital	$ 100,059	$ 96,096
Tier One Leverage Capital to Average Assets	0.0935	0.1032
Tier One Leverage Capital Required for Capital Adequacy	$ 42,808	$ 37,263
Tier One Leverage Capital Required for Capital Adequacy to Average Assets	0.0400	0.0400
Tier One Leverage Capital Required to be Well Capitalized	$ 53,509	$ 46,579
Tier One Leverage Capital Required to be Well Capitalized to Average Assets	0.0500	0.0500
Common Equity Tier One Capital [Abstract]
Common Equity Tier One Capital Amount	$ 100,059	$ 96,096
Common Equity Tier One Captial To Risk Weighted Assets	0.1623	0.1727
Common Equity Tier One Captial Required For Capital Adequacy	$ 27,742	$ 25,042
Common Equity Tier One Captial Required for Capital Adequacy To Risk Weighted Assets	4.50%	4.50%
Common Equity Tier One Captial Required For Well Capitalized	$ 40,072	$ 36,171
Common Equity Tier One Captial Required For Well Capitalized To Risk Weighted Assets	6.50%	6.50%
Tier One Risk Based Capital [Abstract]
Tier One Risk Based Capital	$ 100,059	$ 96,096
Tier One Risk Based Capital to Risk Weighted Assets	0.1623	0.1727
Tier One Risk Based Capital Required for Capital Adequacy	$ 36,990	$ 33,389
Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	0.0600	0.0600
Tier One Risk Based Capital Required to be Well Capitalized	$ 49,320	$ 44,519
Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	0.0800	0.0800
Total Risk-Based Capital [Abstract]
Total Risk Based Capital	$ 105,163	$ 101,906
Total Risk Based Capital to Risk Weighted Assets	0.1706	0.1831
Total Risk Based Capital Required for Capital Adequacy	$ 49,320	$ 44,519
Total Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	0.0800	0.0800
Total Risk Based Capital Required to be Well Capitalized	$ 61,649	$ 55,648
Total Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	0.1000	0.1000