Supplementary Regulatory Capital Disclosure (Details) $ in Millions	Jun. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Debt Disclosure [Abstract]
Total Capital to risk-weighted assets, Actual Amount	$ 728.8	$ 595.6
Total Capital to risk-weighted assets, Actual, Ratio	0.1587	0.1516
Total Capital to risk-weighted assets, Minimum for Capital Adequacy Purposes Amount	$ 367.4	$ 314.4
Total Capital to risk-weighted assets, Minimum for Capital Adequacy Purposes, Ratio	0.0800	0.0800
Total Capital to risk-weighted assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 459.3	$ 393.0
Total Capital to risk-weighted assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	0.1000	0.1000
Tier 1 Capital to average assets, Actual Amount	$ 671.2	$ 546.2
Tier 1 Capital to average assets, Actual, Ratio	0.1072	0.1022
Tier 1 Capital to average assets, Minimum for Capital Adequacy Purposes Amount	$ 250.5	$ 213.7
Tier 1 Capital to average assets, Minimum for Capital Adequacy Purposes, Ratio	0.0400	0.0400
Tier 1 Capital to average assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 313.2	$ 267.1
Tier 1 Capital to average assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provision, Ratio	0.0500	0.0500
Common equity to risk-weighted assets, Actual Amount	$ 671.2	$ 546.2
Common equity to risk-weighted assets, Actual, Ratio	14.62%	13.90%
Common equity to risk-weighted assets, Minimum for Capital Adequacy Purposes Amount	$ 206.7	$ 176.8
Common equity to risk-weighted assets, Minimum for Capital Adequacy Purposes, Ratio	4.50%	4.50%
Common equity to risk-weighted assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 298.5	$ 255.4
Common equity to risk-weighted assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio	6.50%	6.50%
Tier 1 Capital to risk-weighted assets, Actual Amount	$ 671.2	$ 546.2
Tier 1 Capital to risk-weighted assets, Actual, Ratio	0.1462	0.1390
Tier 1 Capital to risk-weighted assets, Minimum for Capital Adequacy Purposes Amount	$ 275.6	$ 235.8
Tier 1 Capital to risk-weighted assets, Ratio	0.0600	0.0600
Tier 1 Capital to risk-weighted assets, Minimum to Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 367.4	$ 314.4
Tier 1 Capital to risk-weighted assets, Ratio	0.0800	0.0800