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Related Party Disclosures (Nephila) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Related Party Transaction [Line Items]
Gross premium volume	$ 3,788,185	$ 3,280,049	$ 7,224,197	$ 6,678,336
Premiums ceded	1,580,492	1,180,254	2,798,726	2,413,807
Program services and other fronting [Member] | Nephila Reinsurers [Member]
Related Party Transaction [Line Items]
Gross premium volume	297,393	175,185	534,288	490,772
Premiums ceded	297,393	175,185	534,288	490,772
Underwriting [Member] | Nephila Reinsurers [Member]
Related Party Transaction [Line Items]
Premiums ceded	$ 16,384	$ 13,512	$ 29,847	$ 29,619

X

- Definition

Amount of written premiums ceded to other entities.

+ References

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+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(c)(2)(i))
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