Loans (Narrative) (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2023 USD ($) loan tDR_Loan	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2022 USD ($) loan	Dec. 31, 2022 USD ($) tDR_Loan	Dec. 31, 2022 USD ($) Loan	Dec. 31, 2020 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Deferred loan fee and premiums, net	$ (3,900,000)	$ 3,000,000
Deferred loan fees and premiums include net deferred fees paid by customers	8,300,000	7,300,000	$ 7,300,000	$ 7,300,000	$ 7,300,000	$ 7,300,000
Total deferred fee and premiums	4,400,000	4,300,000	4,300,000	4,300,000	4,300,000	4,300,000
Gross loans	$ 1,844,321,000	1,821,407,000	1,821,407,000	1,821,407,000	1,821,407,000	1,821,407,000
Service rights retained, percent of outstanding balance	0.25%
Service rights retained, amount	$ 19,100,000	19,500,000	19,500,000	19,500,000	19,500,000	19,500,000
Non-accrual Delinquent Loans	727,000	655,000	655,000	655,000	655,000	655,000
Nonaccrual	$ 8,124,000	6,115,000	$ 6,115,000	$ 6,115,000	$ 6,115,000	$ 6,115,000
Number of BEFDs loans modified in the period | loan	0			0
Total BEFDs modifications	1				2	1
Reserve amount	$ 27,000	28,000
Financing receivable, excluding accrued interest, modified in period, amount	0
Reserve for number of contracts | Loan						1
Number of contracts for disposal | Loan						0
Principal curtailment	$ 1,000	$ 18,000
Loan Delinquency
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	0.08%	0.06%	0.06%	0.06%	0.06%	0.06%
Nonaccrual	$ 1,500,000	$ 1,000,000	$ 1,000,000	$ 1,000,000	$ 1,000,000	$ 1,000,000
Increase (decrease) In loan delinquency		$ 400,000
Nonaccrual Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	0.44%	0.34%	0.34%	0.34%	0.34%	0.34%
Increase (decrease) in finance receivables		$ 2,000,000
Non-accrual Delinquent Loans	$ 8,100,000	6,100,000	$ 6,100,000	$ 6,100,000	$ 6,100,000	$ 6,100,000
Nonaccrual Loans With No Impairment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	6,700,000	6,000,000	$ 6,000,000	6,000,000	6,000,000	6,000,000
Percentage of current loans on total non accrual loans			89.00%
Interest due to debt	43,000	22,000
Nonaccrual Loans With No Impairment | Total Past Due
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual		5,500,000	$ 5,500,000	5,500,000	5,500,000	5,500,000
Nonaccrual Loans With Impairment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Nonaccrual	1,400,000	100,000	$ 100,000	100,000	100,000	100,000
Payment for principal		100,000
Payment for interest		700,000
Percentage of delinquent loans on total non accrual loans			11.00%
Interest due to debt	5,000	1,000
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual Delinquent Loans	0	0	$ 0	0	0	0
Nonaccrual	$ 5,889,000	$ 4,602,000	$ 4,602,000	$ 4,602,000	$ 4,602,000	$ 4,602,000
Commercial Real Estate | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period (in years)	3 years
Commercial Real Estate | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period (in years)	20 years
Commercial Real Estate | Commercial Construction Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	6.20%	6.90%	6.90%	6.90%	6.90%	6.90%
Percent of appraised value or sales price	80.00%
Residential First Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual Delinquent Loans		$ 0	$ 0	$ 0	$ 0	$ 0
Nonaccrual		0	0	0	0	0
Residential First Mortgages | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period (in years)	10 years
Residential First Mortgages | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period (in years)	30 years
Residential Rentals
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-accrual Delinquent Loans	$ 274,000	449,000	449,000	449,000	449,000	449,000
Nonaccrual	$ 1,631,000	1,142,000	1,142,000	1,142,000	1,142,000	1,142,000
Residential Rentals | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period (in years)	3 years
Residential Rentals | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period (in years)	20 years
U.S. SBA PPP
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unamortized loan commitment and origination fees and unamortized discounts or premiums		8,000	8,000	8,000	8,000	8,000
Deferred loan fees and premiums included in deferred fees paid by SBA		9,000	9,000	9,000	9,000	9,000
Offset by net deferred premiums paid to purchase loans		1,000	1,000	1,000	1,000	1,000
Adjustable Rate Residential First Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans	$ 1,800,000,000	$ 1,820,000,000	$ 1,820,000,000	$ 1,820,000,000	$ 1,820,000,000	$ 1,820,000,000
Adjustable Rate Residential First Mortgage | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	49.60%	50.40%	50.40%	50.40%	50.40%	50.40%
Gross loans	$ 914,800,000	$ 918,400,000	$ 918,400,000	$ 918,400,000	$ 918,400,000	$ 918,400,000
Adjustable Rate Residential First Mortgage | Residential First Mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage status of loan in portfolio	0.70%	0.70%	0.70%	0.70%	0.70%	0.70%
Gross loans	$ 12,900,000	$ 13,100,000	$ 13,100,000	$ 13,100,000	$ 13,100,000	$ 13,100,000
Commercial loans | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Bank exposure, threshold limit for credit rating (or greater)							$ 1,000,000
Commercial loans | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt maturity period (in years)	5 years