Schedule I-Summary Of Investments-Other than Investments in Related Parties (Details) $ in Thousands	Dec. 31, 2022 USD ($)
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	$ 3,376,319
Fair Value	3,272,301
Amount at which shown in the balance sheet	3,272,301
Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	2,945,273
Fair Value	2,666,950
Amount at which shown in the balance sheet	2,666,950
Fixed Income Securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	2,945,273
Fair Value	2,666,950
Amount at which shown in the balance sheet	2,666,950
Equity Securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	328,019
Fair Value	498,382
Amount at which shown in the balance sheet	498,382
Ind Misc & All Other
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	109,530
Fair Value	179,643
Amount at which shown in the balance sheet	179,643
ETFs (Ind/misc)
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	218,489
Fair Value	318,739
Amount at which shown in the balance sheet	318,739
Cash and Short-term Investments
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	59,047
Fair Value	59,047
Amount at which shown in the balance sheet	59,047
Other Invested Assets
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	43,980
Fair Value	47,922
Amount at which shown in the balance sheet	47,922
U.S. government \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	462,884
Fair Value	454,021
Amount at which shown in the balance sheet	454,021
U.S. Agency \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	75,074
Fair Value	73,063
Amount at which shown in the balance sheet	73,063
Non-U.S. government & agency \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	6,798
Fair Value	5,847
Amount at which shown in the balance sheet	5,847
Agency MBS \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	373,687
Fair Value	331,806
Amount at which shown in the balance sheet	331,806
ABS/CMBS/MBS \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	276,126
Fair Value	240,736
Amount at which shown in the balance sheet	240,736
Corporate Debt \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	1,122,097
Fair Value	1,034,330
Amount at which shown in the balance sheet	1,034,330
Municipal \| Available for sale securities
SCHEDULE I - SUMMARY OF INVESTMENTS-OTHER THAN INVESTMENTS IN RELATED PARTIES
Cost	628,607
Fair Value	527,147
Amount at which shown in the balance sheet	$ 527,147

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Amount of investment held by insurance company, excluding investment in related party.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
-Section S99
-Paragraph 7
-Subparagraph (SX 210.12-15(Column D))
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Cost of investment held by insurance company, excluding investment in related party.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 320
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