v3.26.3
Regulatory Capital - Regulatory Capital Ratios (Details)
$ in Thousands
Sep. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations    
Total capital $ 499,178 $ 463,447
Total capital to risk-weighted assets 0.1225 0.1224
Total capital, Minimum Required for Capital Adequacy Purposes $ 326,114 $ 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 $ 428,025 $ 397,578
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets 10.50% 10.50%
Tier 1 capital $ 405,434 $ 370,786
Tier 1 capital to risk-weighted assets 0.0995 0.0979
Tier 1 capital, Minimum Required for Capital Adequacy Purposes $ 244,586 $ 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 $ 346,497 $ 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 $ 393,442 $ 358,794
Common equity tier 1 capital to risk-weighted assets 9.65% 9.48%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes $ 183,439 $ 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 $ 285,350 $ 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 $ 405,434 $ 370,786
Tier 1 leverage capital to average assets 0.0922 0.0886
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes $ 175,886 $ 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 $ 175,886 $ 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 $ 495,485 $ 460,423
Total capital to risk-weighted assets 0.1215 0.1216
Total capital, Minimum Required for Capital Adequacy Purposes $ 326,122 $ 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 $ 428,035 $ 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 $ 407,652 $ 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 $ 456,636 $ 422,567
Tier 1 capital to risk-weighted assets 0.112 0.1116
Tier 1 capital, Minimum Required for Capital Adequacy Purposes $ 244,591 $ 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 $ 346,504 $ 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 $ 326,122 $ 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 $ 456,636 $ 422,567
Common equity tier 1 capital to risk-weighted assets 11.20% 11.16%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes $ 183,444 $ 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 $ 285,357 $ 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 $ 264,974 $ 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 $ 456,636 $ 422,567
Tier 1 leverage capital to average assets 0.104 0.1011
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes $ 175,630 $ 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 $ 175,630 $ 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 $ 219,537 $ 209,046
Tier 1 leverage capital to average assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements 0.05 0.05