Regulatory Matters - Schedule of Company's and Bank's Actual Capital Amounts and Ratios (Details) $ in Thousands	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Actual Amount	$ 167,462	$ 81,827
Total Capital (to Risk Weighted Assets), Actual Ratio	24.05	17.77
Total Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 73,119	$ 48,355
Total Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	10.50	10.50
Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount		$ 46,052
Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio		10.00
Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 161,070	$ 77,356
Tier 1 Capital (to Risk Weighted Assets), Actual Ratio	23.13	16.80
Tier 1 Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 59,192	$ 39,144
Tier 1 Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	8.50	8.50
Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount		$ 36,842
Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio		8.00
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 161,070	$ 77,356
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio	23.13	16.80
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 48,746	$ 32,236
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	7.00	7.00
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount		$ 29,934
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio		6.50
Tier 1 Capital (to Average Assets), Actual Amount	$ 161,070	$ 77,356
Tier 1 Capital (to Average Assets), Actual Ratio	19.50	11.83
Tier 1 Capital (to Average Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 33,038	$ 26,164
Tier 1 Capital (to Average Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	4.00	4.00
Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount		$ 32,705
Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio		5.00
Everett Co-operative Bank
Schedule of Capitalization [Line Items]
Total Capital (to Risk Weighted Assets), Actual Amount	$ 135,598
Total Capital (to Risk Weighted Assets), Actual Ratio	19.42
Total Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 73,299
Total Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	10.50
Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 69,809
Total Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00
Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 129,206
Tier 1 Capital (to Risk Weighted Assets), Actual Ratio	18.51
Tier 1 Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 59,338
Tier 1 Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	8.50
Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 55,847
Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Amount	$ 129,206
Common Equity Tier 1 Capital (to Risk Weighted Assets), Actual Ratio	18.51
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 48,866
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	7.00
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 45,376
Common Equity Tier 1 Capital (to Risk Weighted Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.50
Tier 1 Capital (to Average Assets), Actual Amount	$ 129,206
Tier 1 Capital (to Average Assets), Actual Ratio	15.62
Tier 1 Capital (to Average Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 33,083
Tier 1 Capital (to Average Assets), Minimum For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	4.00
Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 41,353
Tier 1 Capital (to Average Assets), Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00