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Investment Securities - Significant Unobservable Inputs (Details) $ in Millions | 6 Months Ended | 12 Months Ended
--- | --- | ---
Jun. 30, 2021 USD ($) | Jun. 30, 2020 USD ($) | Dec. 31, 2020 USD ($)
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Investments in kudu participation contracts | $ 11.3 | $ 57.4 |
Kudu |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Investments in kudu participation contracts |  |  | $ 118.2
Kudu Investments | Discount rate | Standard Poors NR Rating | Minimum |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Fair value, discount rate | 18.00% |  | 18.00%
Kudu Investments | Discount rate | Standard Poors NR Rating | Maximum |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Fair value, discount rate | 23.00% |  | 23.00%
Kudu Investments | Terminal Multiple | Standard Poors NR Rating | Minimum |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Terminal Cash Flow Exit Multiple | 7 |  | 7
Kudu Investments | Terminal Multiple | Standard Poors NR Rating | Maximum |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Terminal Cash Flow Exit Multiple | 13 |  | 12
PassportCard/DavidShield |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Investments in kudu participation contracts |  |  | $ 15.0
Private debt investments | Discount rate | Standard Poors NR Rating | Minimum |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Fair value, discount rate | 3.00% |  | 4.00%
Private debt investments | Discount rate | Standard Poors NR Rating | Maximum |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Fair value, discount rate | 8.00% |  | 8.00%
Other long-term investments | Discount rate | Standard Poors NR Rating | Minimum |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Fair value, discount rate | 20.00% |  | 20.00%
Other long-term investments | Discount rate | Standard Poors NR Rating | Maximum |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Fair value, discount rate | 24.00% |  | 24.00%
TIG Advisors LLC | Kudu |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Investments in kudu participation contracts | $ 10.9 |  |
TK Partners LLC | Kudu |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Investments in kudu participation contracts | 0.4 |  |
Level 3 | Kudu Investments | Standard Poors NR Rating | Discounted cash flow |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Assets, fair value | 455.5 |  | $ 400.6
Level 3 | PassportCard/DavidShield | Standard Poors NR Rating | Discounted cash flow |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Assets, fair value | $ 95.0 |  | $ 95.0
Level 3 | PassportCard/DavidShield | Discount rate | Standard Poors NR Rating |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Fair value, discount rate | 23.00% |  | 23.00%
Level 3 | PassportCard/DavidShield | Measurement Input, Long-term Revenue Growth Rate | Standard Poors NR Rating |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Terminal Revenue Growth Rate | 4.00% |  | 4.00%
Level 3 | Elementum Holdings L.P. | Standard Poors NR Rating | Discounted cash flow |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Assets, fair value | $ 56.7 |  | $ 55.1
Level 3 | Elementum Holdings L.P. | Discount rate | Standard Poors NR Rating |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Fair value, discount rate | 17.00% |  | 17.00%
Level 3 | Elementum Holdings L.P. | Measurement Input, Long-term Revenue Growth Rate | Standard Poors NR Rating |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Terminal Revenue Growth Rate | 4.00% |  | 4.00%
Level 3 | Private debt investments | Standard Poors NR Rating | Discounted cash flow |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Assets, fair value | $ 10.9 |  | $ 17.1
Level 3 | Other long-term investments | Standard Poors NR Rating |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Assets, fair value | 35.5 |  | 27.6
Level 3 | Other long-term investments | Standard Poors NR Rating | Discounted cash flow |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Assets, fair value | $ 20.8 |  | $ 18.8
Level 3 | Other long-term investments | Measurement Input, Long-term Revenue Growth Rate | Standard Poors NR Rating |  |  |
Quantitative information for Level 3 Fair Value Measurements Assets |  |  |
Terminal Revenue Growth Rate | 4.00% |  | 4.00%

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