Fair Value Measurements (Narrative) (Details)		3 Months Ended		9 Months Ended	12 Months Ended
		Sep. 30, 2022 USD ($) loan	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($) loan	Dec. 31, 2021 USD ($) loan
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value, transfers between three levels		$ 0	$ 0
Cash and cash equivalents		722,700,000		$ 722,700,000	$ 601,800,000
Collateral dependent loans		7,900,000		7,900,000
Specific reserves and other write downs on impaired loans		$ 863,000		$ 863,000	$ 978,000
Number of troubled debt restructured loans | loan		11		11	10
Troubled debt restructured loans balance	[1]			$ 5,284,000	$ 1,479,000
Troubled debt restructured loans, specific reserve		$ 447,000		$ 447,000	476,000
Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Constant prepayment rates				3.00%
Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Constant prepayment rates				30.00%
Fair Value, Measurements, Nonrecurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Collateral dependent loans	[2]	$ 7,059,000		$ 7,059,000	$ 3,005,000
Fair Value, Measurements, Nonrecurring [Member] | Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated selling costs				7.00%
Fair Value, Measurements, Nonrecurring [Member] | Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated selling costs				10.00%

[1] Troubled debt restructurings include non-accrual loans of $1.2 million and $656,000 at September 30, 2022 and December 31, 2021, respectively.

[2] The method of valuation approach for the loans evaluated for an allowance for credit losses on an individual loan basis and also for other real estate owned was the market approach based upon appraisals of the underlying collateral by external appraisers, reduced by 7% to 10% for estimated selling costs. Intangible assets are valued based upon internal analyses.