Investments - Equity Method Investments (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Investment	$ 266,823	$ 197,860
Ownership %	47.40%	47.40%
Equity method investments	$ 326,277	$ 204,507
EnhanzedRe
Schedule of Equity Method Investments [Line Items]
Investment	$ 154,050	$ 94,800
Ownership %	47.40%	47.40%
Equity method investments	$ 182,856	$ 94,800
Citco
Schedule of Equity Method Investments [Line Items]
Investment	$ 50,000	$ 50,000
Ownership %	31.90%	31.90%
Equity method investments	$ 51,742	$ 50,812
Monument
Schedule of Equity Method Investments [Line Items]
Investment	$ 26,600	$ 26,600
Ownership %	26.60%	26.60%
Equity method investments	$ 60,598	$ 42,193
Clear Spring
Schedule of Equity Method Investments [Line Items]
Investment	$ 11,210	$ 11,210
Ownership %	20.00%	20.00%
Equity method investments	$ 10,645	$ 10,070
Other
Schedule of Equity Method Investments [Line Items]
Investment	$ 24,963	$ 15,250
Ownership %	30.00%	30.00%
Equity method investments	$ 20,436	$ 6,632
Equity Method Investments
Schedule of Equity Method Investments [Line Items]
Unfunded commitments	$ 93,100

This element represents the aggregate cost of investments accounted for under the equity method of accounting.

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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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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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