Fair Value Measurement, Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	$ 632,213	$ 435,080
Assets Recorded at Fair Value on a Non-recurring Basis [Abstract]
Mortgage servicing rights	1,531	1,242
Recurring [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	632,213	435,080
Liabilities Recorded at Fair Value [Abstract]
Liabilities	0	0
Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	86,211	38,891
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	546,002	396,189
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Non-recurring [Member]
Assets Recorded at Fair Value on a Non-recurring Basis [Abstract]
Impaired loans	33	28
Mortgage servicing rights	1,531	1,242
Total assets at fair value	1,564	1,270
Liabilities Recorded at Fair Value [Abstract]
Liabilities	0	0
Non-recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Recorded at Fair Value on a Non-recurring Basis [Abstract]
Impaired loans	0	0
Mortgage servicing rights	0	0
Total assets at fair value	0	0
Non-recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Recorded at Fair Value on a Non-recurring Basis [Abstract]
Impaired loans	0	0
Mortgage servicing rights	0	0
Total assets at fair value	0	0
Non-recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Recorded at Fair Value on a Non-recurring Basis [Abstract]
Impaired loans	33	28
Mortgage servicing rights	1,531	1,242
Total assets at fair value	1,564	1,270
U.S. Treasury Securities [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	86,211	38,891
U.S. Treasury Securities [Member] | Recurring [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	86,211	38,891
U.S. Treasury Securities [Member] | Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	86,211	38,891
U.S. Treasury Securities [Member] | Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
U.S. Treasury Securities [Member] | Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Securities of U.S. Government Agencies and Corporations [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	102,610	106,558
Securities of U.S. Government Agencies and Corporations [Member] | Recurring [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	102,610	106,558
Securities of U.S. Government Agencies and Corporations [Member] | Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Securities of U.S. Government Agencies and Corporations [Member] | Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	102,610	106,558
Securities of U.S. Government Agencies and Corporations [Member] | Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Obligations of States and Political Subdivisions [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	45,985	32,882
Obligations of States and Political Subdivisions [Member] | Recurring [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	45,985	32,882
Obligations of States and Political Subdivisions [Member] | Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Obligations of States and Political Subdivisions [Member] | Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	45,985	32,882
Obligations of States and Political Subdivisions [Member] | Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Collateralized Mortgage Obligations [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	135,652	73,460
Collateralized Mortgage Obligations [Member] | Recurring [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	135,652	73,460
Collateralized Mortgage Obligations [Member] | Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Collateralized Mortgage Obligations [Member] | Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	135,652	73,460
Collateralized Mortgage Obligations [Member] | Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Mortgage-backed Securities [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	261,755	183,289
Mortgage-backed Securities [Member] | Recurring [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	261,755	183,289
Mortgage-backed Securities [Member] | Recurring [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	0	0
Mortgage-backed Securities [Member] | Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	261,755	183,289
Mortgage-backed Securities [Member] | Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets Recorded at Fair Value on a Recurring Basis [Abstract]
Total investments at fair value	$ 0	$ 0