Federal Home Loan Bank of Boston advances (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
F H L B B Advances Total [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Advances from Federal Home Loan Banks
Federal Home Loan Bank, Advance, Maturity, Year Three		4,984
Federal Home Loan Bank, Advance, Maturity, Year Four	7,656	7,655
Long-term Federal Home Loan Bank Advances	$ 7,656	$ 12,639
F H L B B Advances Rate [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank, Advances, Interest Rate
Federal Home Loan Bank, Advance, Maturity, Average Interest Rate, Year Three		1.13%
Federal Home Loan Bank, Advance, Maturity, Average Interest Rate, Year Four	1.39%	1.38%
Federal Home Loan Bank, Advances, Branch of FHLB Bank, Interest Rate	1.39%	1.29%

Amount of borrowings as of the balance sheet date from the Federal Home Loan Bank, which are primarily used to cover shortages in the required reserve balance and liquidity shortages.

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Discloses the single interest rate [if] applicable to the advances from the Federal Home Loan Bank, by branch, as of the Balance Sheet date.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Interest rate of advances made and reported by Federal Home Loan Bank (FHLBank).

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No definition available.

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Including both current and noncurrent portions, Federal Home Loan Bank borrowings initially due beyond one year or beyond the normal operating cycle if longer.

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Weighted average interest rate of advance from Federal Home Loan Bank (FHLBank) due in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Weighted average interest rate of advance from Federal Home Loan Bank (FHLBank) due in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of advance from Federal Home Loan Bank (FHLBank) maturing in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of advance from Federal Home Loan Bank (FHLBank) maturing in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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