Policy Benefits And Losses Claims And Loss Expenses Payable (Present Value Expected Net Premiums) (Details) - USD ($) $ in Thousands		6 Months Ended
	Apr. 01, 2021	Sep. 30, 2023	Sep. 30, 2022	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021
Liability For Future Policy Benefit Expected Net Premium [Roll Forward]
Balance, beginning of the year						$ 123,132
Effect of actual variances from expected variances						2,580
Other	$ 464,481
Effect of changes in discount rate assumptions (AOCI)						337,022
Oxford
Liability For Future Policy Benefit Expected Net Premium [Roll Forward]
Balance, beginning of the year		$ 397,316	$ 488,325	$ 419,687	$ 561,103
Beginning balance at original discount rate		413,303	488,470	437,525	496,048
Effect of changes in cash flow assumptions				0	0
Effect of actual variances from expected variances				(5,831)	1,774
Adjust beginning of year balance				431,694	497,822
Issuances		5,149	16,536
Interest accrual		9,650	11,099
Net premium collected		(33,190)	(36,987)
Other		0	0
Ending balance at original discount rate		413,303	488,470
Effect of changes in discount rate assumptions (AOCI)		(15,987)	(145)
Balance, end of period		397,316	488,325
Life Insurance Segment [Member] | Oxford
Liability For Future Policy Benefit Expected Net Premium [Roll Forward]
Balance, beginning of the year		214,027	249,477	223,118	280,371
Beginning balance at original discount rate		215,677	241,663	225,071	242,741
Effect of changes in cash flow assumptions				0	0
Effect of actual variances from expected variances				(187)	748
Adjust beginning of year balance				224,884	243,489
Issuances		5,072	14,083
Interest accrual		5,554	6,037
Net premium collected		(19,833)	(21,946)
Other		0	0
Ending balance at original discount rate		215,677	241,663
Effect of changes in discount rate assumptions (AOCI)		(1,650)	7,814
Balance, end of period		214,027	249,477
Health Insurance Product Line [Member]
Liability For Future Policy Benefit Expected Net Premium [Roll Forward]
Balance, beginning of the year						4,847
Effect of actual variances from expected variances						0
Other	$ 23,188
Effect of changes in discount rate assumptions (AOCI)						$ 18,341
Health Insurance Product Line [Member] | Oxford
Liability For Future Policy Benefit Expected Net Premium [Roll Forward]
Balance, beginning of the year		183,289	238,848	196,569	280,732
Beginning balance at original discount rate		197,626	246,807	212,454	253,307
Effect of changes in cash flow assumptions				0	0
Effect of actual variances from expected variances				(5,644)	1,026
Adjust beginning of year balance				$ 206,810	$ 254,333
Issuances		77	2,453
Interest accrual		4,096	5,062
Net premium collected		(13,357)	(15,041)
Other		0	0
Ending balance at original discount rate		197,626	246,807
Effect of changes in discount rate assumptions (AOCI)		(14,337)	(7,959)
Balance, end of period		$ 183,289	$ 238,848