Allowance for Credit Losses (Reserve Allowance Various Credit Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Valuation And Qualifying Accounts [Abstract]
March 31, 2023	$ 3,789
March 31, 2024	6,236	$ 3,789
Trade Receivables
Valuation And Qualifying Accounts [Abstract]
March 31, 2023	3,789	8,649
Transition adjustment current expected credit losses	2,447	4,860
Write-offs against allowance	0	0
Recoveries	0	0
March 31, 2024	6,236	3,789
Investments, Fixed Maturities
Valuation And Qualifying Accounts [Abstract]
March 31, 2023	2,101	60
Transition adjustment current expected credit losses	1,049	2,041
Write-offs against allowance	0	0
Recoveries	0	0
March 31, 2024	1,052	2,101
Investments, Other
Valuation And Qualifying Accounts [Abstract]
March 31, 2023	517	501
Transition adjustment current expected credit losses	300	16
Write-offs against allowance	0	0
Recoveries	0	0
March 31, 2024	817	517
Allowance For Credit Loss [Member]
Valuation And Qualifying Accounts [Abstract]
March 31, 2023	6,407	9,210
Transition adjustment current expected credit losses	1,698	2,803
Write-offs against allowance	0	0
Recoveries	0	0
March 31, 2024	$ 8,105	$ 6,407