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Regulatory Capital (Details) $ in Millions | Jan. 01, 2020 USD ($) | Sep. 30, 2021 USD ($) | Dec. 31, 2020 USD ($)
--- | --- | --- | ---
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items] |  |  |
Retained Earnings (Accumulated Deficit) |  | $ 1,026.9 | $ 962.1
Total risk-based capital: |  |  |
Actual, Amount |  | $ 1,642.0 | $ 1,575.7
Actual, Ratio |  | 0.1400 | 0.1419
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 938.0 | $ 888.3
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0800 | 0.0800
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,231.1 | $ 1,165.8
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 10.50% | 10.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,172.5 | $ 1,110.3
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.1000 | 0.1000
Tier 1 risk-based capital: |  |  |
Actual, Amount |  | $ 1,442.6 | $ 1,369.0
Actual, Ratio |  | 0.1230 | 0.1233
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 703.5 | $ 666.2
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0600 | 0.0600
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 996.6 | $ 943.8
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 8.50% | 8.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 938.0 | $ 888.3
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0800 | 0.0800
Common equity tier 1 risk-based capital: |  |  |
Actual, Amount |  | $ 1,358.5 | $ 1,284.9
Actual, Ratio |  | 11.59% | 11.57%
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 527.6 | $ 499.6
Minimum Required for Capital Adequacy Purposes, Ratio |  | 4.50% | 4.50%
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 820.7 | $ 777.2
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 7.00% | 7.00%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 762.1 | $ 721.7
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 6.50% | 6.50%
Leverage capital ratio: |  |  |
Actual, Amount |  | $ 1,442.6 | $ 1,369.0
Actual, Ratio |  | 0.0781 | 0.0816
Banking Regulation, Tier One Leverage Capital, Capital Adequacy, Minimum |  | $ 738.5 | $ 671.0
Capital Adequacy Purposes and Conservation Buffer, Ratio |  | 0.0400 | 0.0400
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 923.1 | $ 838.7
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0500 | 0.0500
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle | $ 24.1 |  |
FIB |  |  |
Total risk-based capital: |  |  |
Actual, Amount |  | $ 1,464.8 | $ 1,426.8
Actual, Ratio |  | 0.1253 | 0.1289
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 935.1 | $ 885.6
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0800 | 0.0800
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 1,227.3 | $ 1,162.3
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 10.50% | 10.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 1,168.9 | $ 1,107.0
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.1000 | 0.1000
Tier 1 risk-based capital: |  |  |
Actual, Amount |  | $ 1,365.4 | $ 1,320.1
Actual, Ratio |  | 0.1168 | 0.1193
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 701.3 | $ 664.2
Minimum Required for Capital Adequacy Purposes, Ratio |  | 0.0600 | 0.0600
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 993.5 | $ 940.9
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 8.50% | 8.50%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 935.1 | $ 885.6
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0800 | 0.0800
Common equity tier 1 risk-based capital: |  |  |
Actual, Amount |  | $ 1,365.4 | $ 1,320.1
Actual, Ratio |  | 11.68% | 11.93%
Minimum Required for Capital Adequacy Purposes, Amount |  | $ 526.0 | $ 498.1
Minimum Required for Capital Adequacy Purposes, Ratio |  | 4.50% | 4.50%
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Amount |  | $ 818.2 | $ 774.9
For Capital Adequacy Purposes Plus Capital Conservation Buffer, Ratio |  | 7.00% | 7.00%
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 759.8 | $ 719.5
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 6.50% | 6.50%
Leverage capital ratio: |  |  |
Actual, Amount |  | $ 1,365.4 | $ 1,320.1
Actual, Ratio |  | 0.0741 | 0.0788
Banking Regulation, Tier One Leverage Capital, Capital Adequacy, Minimum |  | $ 737.2 | $ 669.7
Capital Adequacy Purposes and Conservation Buffer, Ratio |  | 0.0400 | 0.0400
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Amount |  | $ 921.5 | $ 837.2
Minimum to Be Well Capitalized Under Prompt Corrective Action Requirements, Ratio |  | 0.0500 | 0.0500

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- Definition Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
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