Allowance for Credit Losses (Reserve Allowance Various Credit Loss) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Valuation And Qualifying Accounts [Abstract]
March 31, 2020	$ 6,242	$ 4,219
Transition adjustment expected credit loss current	2,968	2,023
Write-offs against allowance	0	0
Recoveries	0	0
March 31, 2021	9,210	6,242
Trade Receivables
Valuation And Qualifying Accounts [Abstract]
March 31, 2020	4,421	3,215
Transition adjustment expected credit loss current	4,228	1,206
Write-offs against allowance	0	0
Recoveries	0	0
March 31, 2021	8,649	4,421
Investments, Fixed Maturities
Valuation And Qualifying Accounts [Abstract]
March 31, 2020	1,320	503
Transition adjustment expected credit loss current	(1,260)	817
Write-offs against allowance	0	0
Recoveries	0	0
March 31, 2021	60	1,320
Investments, Other
Valuation And Qualifying Accounts [Abstract]
March 31, 2020	501	501
Transition adjustment expected credit loss current	0	0
Write-offs against allowance	0	0
Recoveries	0	0
March 31, 2021	$ 501	$ 501