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Investment Securities - Investment in MediaAlpha textual (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2023 | Dec. 31, 2022
Marketing Technology (MediaAlpha) |  |
Subsidiary, Sale of Stock [Line Items] |  |
Ownership interest (as a percent) | 26.80% | 27.10%
Share price (in usd per share) | $ 14.98 |
Investment in MediaAlpha, at fair value | $ 253.8 |
Marketing Technology (MediaAlpha) |  |
Subsidiary, Sale of Stock [Line Items] |  |
Investment owned (in shares) | 16.9 |
Fully diluted ownership interest (as a percent) | 24.30% |
Marketing Technology (MediaAlpha) | IPO |  |
Subsidiary, Sale of Stock [Line Items] |  |
Increase in investment owned (in dollars per share) | $ 1.00 |
Increase in book value per share (in dollars per share) | $ 6.60 |

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