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Regulatory Capital (Regulatory Capital Ratios) (Details) $ in Thousands | Sep. 30, 2023 USD ($) | Dec. 31, 2022 USD ($)
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Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 365,058 | $ 323,893
Total capital to risk-weighted assets | 0.1120 | 0.1126
Total capital, Minimum Required for Capital Adequacy Purposes | $ 260,796 | $ 230,180
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.0800 | 0.0800
Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 342,295 | $ 302,111
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 10.50% | 10.50%
Tier 1 capital | $ 284,974 | $ 264,843
Tier 1 capital to risk-weighted assets | 0.0874 | 0.0920
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 195,597 | $ 172,635
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.0600 | 0.0600
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 277,096 | $ 244,566
Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 8.50% | 8.50%
Common equity tier 1 capital | $ 272,982 | $ 252,851
Common equity tier 1 capital to risk-weighted assets | 8.37% | 8.79%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 146,698 | $ 129,476
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common Equity Tier One Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 228,197 | $ 201,407
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 7.00% | 7.00%
Tier 1 leverage capital | $ 284,974 | $ 264,843
Tier 1 leverage capital to average assets | 0.0865 | 0.0917
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 131,840 | $ 115,464
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 0.0400 | 0.0400
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 131,840 | $ 115,464
Tier One Leverage Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 4.00% | 4.00%
First Business Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 365,705 | $ 323,021
Total capital to risk-weighted assets | 0.1122 | 0.1122
Total capital, Minimum Required for Capital Adequacy Purposes | $ 260,850 | $ 230,367
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.0800 | 0.0800
Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 342,366 | $ 302,357
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 10.50% | 10.50%
Total capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 326,063 | $ 287,959
Total capital to risk-weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.1000 | 0.1000
Tier 1 capital | $ 335,012 | $ 298,312
Tier 1 capital to risk-weighted assets | 0.1027 | 0.1036
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 195,638 | $ 172,775
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 0.0600 | 0.0600
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 277,154 | $ 244,765
Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 8.50% | 8.50%
Tier 1 capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 260,850 | $ 230,367
Tier 1 capital to risk weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.0800 | 0.0800
Common equity tier 1 capital | $ 335,012 | $ 298,312
Common equity tier 1 capital to risk-weighted assets | 10.27% | 10.36%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 146,728 | $ 129,581
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common Equity Tier One Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 228,244 | $ 201,571
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 7.00% | 7.00%
Common equity tier 1 capital, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | $ 211,941 | $ 187,173
Common equity tier 1 capital to risk-weighted assets, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | 6.50% | 6.50%
Tier 1 leverage capital | $ 335,012 | $ 298,312
Tier 1 leverage capital to average assets | 0.1016 | 0.1034
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 131,845 | $ 115,402
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 0.0400 | 0.0400
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 131,845 | $ 115,402
Tier One Leverage Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 4.00% | 4.00%
Tier 1 leverage capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 164,807 | $ 144,252
Tier 1 leverage capital to average assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 0.0500 | 0.0500

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