v3.26.1
Regulatory Capital - Regulatory Capital Ratios (Details)
$ in Thousands
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations    
Total capital $ 486,735 $ 463,447
Total capital to risk-weighted assets 0.1221 0.1224
Total capital, Minimum Required for Capital Adequacy Purposes $ 318,793 $ 302,917
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes 0.08 0.08
Capital Required for Capital Adequacy Plus Capital Conservation Buffer $ 418,415 $ 397,578
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets 10.50% 10.50%
Tier 1 capital $ 391,971 $ 370,786
Tier 1 capital to risk-weighted assets 0.0984 0.0979
Tier 1 capital, Minimum Required for Capital Adequacy Purposes $ 239,094 $ 227,188
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes 0.06 0.06
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer $ 338,717 $ 321,849
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 $ 379,979 $ 358,794
Common equity tier 1 capital to risk-weighted assets 9.54% 9.48%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes $ 179,321 $ 170,391
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 $ 278,944 $ 265,052
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets 7.00% 7.00%
Tier 1 leverage capital $ 391,971 $ 370,786
Tier 1 leverage capital to average assets 0.0911 0.0886
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes $ 172,019 $ 167,376
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes 0.04 0.04
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer $ 172,019 $ 167,376
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 $ 485,212 $ 460,423
Total capital to risk-weighted assets 0.1218 0.1216
Total capital, Minimum Required for Capital Adequacy Purposes $ 318,817 $ 302,929
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes 0.08 0.08
Capital Required for Capital Adequacy Plus Capital Conservation Buffer $ 418,448 $ 397,594
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 $ 398,522 $ 378,661
Total capital to risk-weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements 0.10 0.10
Tier 1 capital $ 445,313 $ 422,567
Tier 1 capital to risk-weighted assets 0.1117 0.1116
Tier 1 capital, Minimum Required for Capital Adequacy Purposes $ 239,113 $ 227,197
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes 0.06 0.06
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer $ 338,743 $ 321,862
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 $ 318,817 $ 302,929
Tier 1 capital to risk weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements 0.08 0.08
Common equity tier 1 capital $ 445,313 $ 422,567
Common equity tier 1 capital to risk-weighted assets 11.17% 11.16%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes $ 179,335 $ 170,398
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 $ 278,965 $ 265,063
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 $ 259,039 $ 246,130
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 $ 445,313 $ 422,567
Tier 1 leverage capital to average assets 0.1037 0.1011
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes $ 171,774 $ 167,237
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes 0.04 0.04
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer $ 171,774 $ 167,237
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 $ 214,718 $ 209,046
Tier 1 leverage capital to average assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements 0.05 0.05