Loans and Allowance for loan losses (Narrative) (Details)	12 Months Ended
Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan	Dec. 31, 2019 loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Amount of loan	$ 1,440,000	$ 1,571,000
Number of loans default \| loan	3	3
Number of new loans default	0	0
Balance of capitalized servicing rights	$ 2,633,000	$ 2,390,000
Aggregate balances of loans serviced to participants	3,962,000	4,291,000
Aggregate balances of loans serviced to third party	314,953,000	300,700,000
Loans and Leases Receivable, Impaired, Commitment to Lend	0	0
Amount of consumer mortgages and loans secured by residential real estate properties in process of foreclosure	935,000	636,000
Mortgage Servicing Rights (MSR) Impairment (Recovery)	0	0
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans default \| loan			2
Home equity
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans default \| loan			1
Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principal balances of loans held for sale	$ 3,950,000	$ 2,718,000

Number of new additional financing receivables that have been modified by troubled debt restructurings.

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Represents amount of outstanding balance of loan serviced for third party.

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No definition available.

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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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The undiscounted sum of all amounts, including amounts deemed principal, interest, fees, penalties, and other under the loan, owed to the investor at the reporting date, whether or not currently due and whether or not any such amounts have been written or charged off by the investor. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

+ References

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Principal amount of transferred financial assets in which the transferor has continuing involvement with the assets underlying the transaction. Continuing involvement includes, but is not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets.

+ References

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Number of financing receivables that have been modified by troubled debt restructurings.

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Amount of financing receivable modified as troubled debt restructuring.

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Amount of unfunded portion of contractual agreement to lend funds to borrower for financing receivable modified as troubled debt restructuring.

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Recorded investment of consumer mortgage loan receivables secured by residential real estate properties for which formal foreclosure proceedings are in process.

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The adjustment to the carrying value of the rights retained or purchased to service mortgages. These adjustments are made when the estimate of the fair value is changed. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Aggregate amount of servicing assets that are subsequently measured at fair value and servicing assets that are subsequently measured using the amortization method.

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