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Regulatory Capital (Regulatory Capital Ratios) (Details) - USD ($) $ in Thousands | Mar. 31, 2016 | Dec. 31, 2015
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Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 192,670 | $ 189,163
Total capital to risk-weighted assets | 11.24% | 11.11%
Total capital, Minimum Required for Capital Adequacy Purposes | $ 137,131 | $ 136,208
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 8.00% | 8.00%
Tier 1 capital | $ 153,531 | $ 149,920
Tier 1 capital to risk-weighted assets | 8.96% | 8.81%
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 102,848 | $ 102,156
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 6.00% | 6.00%
Common equity tier 1 capital | $ 143,531 | $ 139,920
Common equity tier 1 capital to risk-weighted assets | 8.37% | 8.22%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 77,136 | $ 76,617
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Tier 1 capital | $ 153,531 | $ 149,920
Tier 1 leverage capital to average assets | 8.44% | 8.63%
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 72,805 | $ 69,466
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 4.00% | 4.00%
First Business Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 145,732 | $ 141,388
Total capital to risk-weighted assets | 11.43% | 11.12%
Total capital, Minimum Required for Capital Adequacy Purposes | $ 102,002 | $ 101,754
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 8.00% | 8.00%
Total capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 127,502 | $ 127,193
Total capital to risk-weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 10.00% | 10.00%
Tier 1 capital | $ 132,943 | $ 128,852
Tier 1 capital to risk-weighted assets | 10.43% | 10.13%
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 76,501 | $ 76,316
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 6.00% | 6.00%
Tier 1 capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 102,002 | $ 101,754
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 | $ 132,943 | $ 128,852
Common equity tier 1 capital to risk-weighted assets | 10.43% | 10.13%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 57,376 | $ 57,237
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common equity tier 1 capital, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | $ 82,877 | $ 110,669
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 capital | $ 132,943 | $ 128,852
Tier 1 leverage capital to average assets | 10.30% | 10.44%
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 51,647 | $ 49,359
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 4.00% | 4.00%
Tier 1 leverage capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 64,559 | $ 61,698
Tier 1 leverage capital to average assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 5.00% | 5.00%
First Business Bank - Milwaukee |  |
Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 21,170 | $ 20,931
Total capital to risk-weighted assets | 11.74% | 12.03%
Total capital, Minimum Required for Capital Adequacy Purposes | $ 14,425 | $ 13,914
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 8.00% | 8.00%
Total capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 18,032 | $ 17,392
Total capital to risk-weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 10.00% | 10.00%
Tier 1 capital | $ 19,350 | $ 19,172
Tier 1 capital to risk-weighted assets | 10.73% | 11.02%
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 10,819 | $ 10,435
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 6.00% | 6.00%
Tier 1 capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 14,425 | $ 13,914
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 | $ 19,350 | $ 19,172
Common equity tier 1 capital to risk-weighted assets | 10.73% | 11.02%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 8,114 | $ 7,826
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common equity tier 1 capital, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | $ 11,721 | $ 82,675
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 capital | $ 19,350 | $ 19,172
Tier 1 leverage capital to average assets | 7.38% | 7.81%
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 10,485 | $ 9,821
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 4.00% | 4.00%
Tier 1 leverage capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 13,106 | $ 12,276
Tier 1 leverage capital to average assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 5.00% | 5.00%
Alterra Bank |  |
Compliance with Regulatory Capital Requirements under Banking Regulations |  |
Total capital | $ 31,464 | $ 30,300
Total capital to risk-weighted assets | 12.37% | 11.39%
Total capital, Minimum Required for Capital Adequacy Purposes | $ 20,345 | $ 21,279
Total capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 8.00% | 8.00%
Total capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 25,432 | $ 26,598
Total capital to risk-weighted assets, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | 10.00% | 10.00%
Tier 1 capital | $ 29,390 | $ 28,278
Tier 1 capital to risk-weighted assets | 11.56% | 10.63%
Tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 15,259 | $ 15,959
Tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 6.00% | 6.00%
Tier 1 capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 20,345 | $ 21,279
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 | $ 29,390 | $ 28,278
Common equity tier 1 capital to risk-weighted assets | 11.56% | 10.63%
Common equity tier 1 capital, Minimum Required for Capital Adequacy Purposes | $ 11,444 | $ 11,969
Common equity tier 1 capital to risk-weighted assets, Minimum Required for Capital Adequacy Purposes | 4.50% | 4.50%
Common equity tier 1 capital, Minimum Required to Be Well Capitalized Under Prompt Corrective Action Requirements | $ 16,530 | $ 11,305
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 capital | $ 29,390 | $ 28,278
Tier 1 leverage capital to average assets | 9.45% | 9.89%
Tier 1 leverage capital, Minimum Required for Capital Adequacy Purposes | $ 12,440 | $ 11,441
Tier 1 leverage capital to average assets, Minimum Required for Capital Adequacy Purposes | 4.00% | 4.00%
Tier 1 leverage capital, Minimum Required to be Well Capitalized Under Prompt Corrective Action Requirements | $ 15,551 | $ 14,301
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 The amount of total capital as defined in the regulations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47304-110998 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47080-110998 + Details
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- Definition The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826 + Details
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- Definition The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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- Definition Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 + Details
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- Definition The minimum amount of Tier 1 Leverage Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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- Definition The minimum amount of Tier 1 Leverage Capital for capital adequacy purposes divided by average assets as defined in the regulations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826 + Details
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- Definition The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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- Definition The amount of Tier 1 Leverage Capital required to be categorized as well capitalized divided by average assets as defined in the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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- Definition Tier 1 Risk Based Capital as defined in the regulations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 + Details
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- Definition The minimum amount of Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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- Definition The minimum Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958570-112826 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1H -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826 + Details
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- Definition The amount of Tier 1 Risk Based Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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- Definition The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826 + Details
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