Allowance for Credit Losses (Reserve Allowance for Various Credit Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2024	Mar. 31, 2024
Valuation And Qualifying Accounts [Abstract]
March 31, 2022	$ 8,105	$ 6,407
Transition adjustment current expected credit losses	3,621	1,698
December 31, 2023	11,726	8,105
Trade Receivables
Valuation And Qualifying Accounts [Abstract]
March 31, 2022	6,236	3,789
Transition adjustment current expected credit losses	2,047	2,447
December 31, 2023	8,283	6,236
Investments, Fixed Maturities
Valuation And Qualifying Accounts [Abstract]
March 31, 2022	1,052	2,101
Transition adjustment current expected credit losses	1,943	1,049
December 31, 2023	2,995	1,052
Investments, Other
Valuation And Qualifying Accounts [Abstract]
March 31, 2022	817	517
Transition adjustment current expected credit losses	369	300
December 31, 2023	$ 448	$ 817