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Regulatory Capital (Regulatory Capital Ratios) (Details) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017
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Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 225,160 | $ 214,501
Total capital to risk-weighted assets | 12.05% | 11.98%
Total capital, Minimum Required for Capital Adequacy Purposes | $ 149,515 | $ 143,219
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 8.00% | 8.00%
Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 184,558 | $ 165,597
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 9.875% | 9.25%
Tier 1 capital | $ 178,220 | $ 169,176
Tier 1 capital to risk-weighted assets | 9.54% | 9.45%
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 112,136 | $ 107,414
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 6.00% | 6.00%
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 147,179 | $ 129,792
Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 7.875% | 7.25%
Common equity tier 1 capital | $ 168,191 | $ 159,157
Common equity tier 1 capital to risk-weighted assets | 9.00% | 8.89%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 84,102 | $ 80,561
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 | $ 119,145 | $ 102,939
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 6.375% | 5.75%
Tier 1 leverage capital | $ 178,220 | $ 169,176
Tier 1 leverage capital to average assets | 9.34% | 9.54%
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 76,324 | $ 70,920
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 4.00% | 4.00%
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 76,324 | $ 70,920
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 | $ 217,620 | $ 207,986
Total capital to risk-weighted assets | 11.70% | 11.66%
Total capital, Minimum Required for Capital Adequacy Purposes | $ 148,847 | $ 142,736
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 8.00% | 8.00%
Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 183,733 | $ 165,038
Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 9.875% | 9.25%
Total capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 186,058 | $ 178,420
Total capital to risk-weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 10.00% | 10.00%
Tier 1 capital | $ 194,435 | $ 186,374
Tier 1 capital to risk-weighted assets | 10.45% | 10.45%
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 111,635 | $ 107,052
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 6.00% | 6.00%
Tier One Risk Based Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 146,521 | $ 129,354
Tier One Risk Based Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 7.875% | 7.25%
Tier 1 capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 148,847 | $ 142,736
Tier 1 capital to risk weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 8.00% | 8.00%
Common equity tier 1 capital | $ 194,435 | $ 186,374
Common equity tier 1 capital to risk-weighted assets | 10.45% | 10.45%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 83,726 | $ 80,289
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 | $ 118,612 | $ 102,591
Common Equity Tier One Capital Required for Capital Adequacy Plus Conservation Buffer to Risk Weighted Assets | 6.375% | 5.75%
Common equity tier 1 capital, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | $ 120,938 | $ 115,973
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 | $ 194,435 | $ 186,374
Tier 1 leverage capital to average assets | 10.24% | 10.56%
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 75,968 | $ 70,617
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 4.00% | 4.00%
Tier One Leverage Capital Required for Capital Adequacy Plus Capital Conservation Buffer | $ 75,968 | $ 70,617
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 | $ 94,961 | $ 88,272
Tier 1 leverage capital to average assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 5.00% | 5.00%

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- Definition Tier 1 Risk Based Capital as defined in the regulations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84167132&loc=SL5958568-112826 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=84167132&loc=d3e65071-112826 + Details
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