Investment Securities - Investment in MediaAlpha textual (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Marketing Technology (MediaAlpha)
Subsidiary, Sale of Stock [Line Items]
Tender offer purchase price	$ 5.9
Purchase price (in dollars per share)	$ 10.00
Ownership interest (as a percent)	35.70%	35.70%	27.10%
Share price (in usd per share)	$ 10.31	$ 10.31
Investment in MediaAlpha, at fair value	$ 235.7	$ 235.7
Marketing Technology (MediaAlpha)
Subsidiary, Sale of Stock [Line Items]
Investment owned (in shares)	22.9	22.9
Fully diluted ownership interest (as a percent)	33.00%	33.00%
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)		$ 9.00

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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Number of shares of investment owned.

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The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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Price of a single share of a number of saleable stocks of a company.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Investment Owned, Increase (Decrease) in Value, Book Value Per Share

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Investment Owned, Increase (Decrease) in Value, Per Share

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Purchase Price, Equity Method Investment

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