Life Insurance Liabilities (Sensitive Life Insurance Type Products) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Interest expense	$ 71,498,000	$ 63,943,000	$ 138,716,000	$ 124,541,000
Life Insurance Segment [Member] | Oxford
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Gross premiums	$ 25,043,000	$ 26,667,000	25,043,000	26,667,000
Interest expense			$ 7,589,000	$ 7,612,000
Expected future lifetime (persistency) of policies in force (years)	6 years 9 months 18 days	6 years 10 months 24 days	6 years 9 months 18 days	6 years 10 months 24 days
Weighted average original interest rate of the liability for future policy benefits	4.97%	5.00%	4.97%	5.00%
Weighted average current interest rate of the liability for future policy benefits	5.13%	4.65%	5.13%	4.65%
Life Insurance Segment [Member] | Oxford | Expected gross premiums:
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Undiscounted balance	$ 723,862,000	$ 761,261,000	$ 723,862,000	$ 761,261,000
Discounted balance at original discount rate	272,992,000	299,161,000	272,992,000	299,161,000
Discounted balance at current discount rate	266,964,000	296,505,000	266,964,000	296,505,000
Life Insurance Segment [Member] | Oxford | Expected policy benefits:
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Undiscounted balance	350,890,000	387,141,000	350,890,000	387,141,000
Discounted balance at original discount rate	503,526,000	523,777,000	503,526,000	523,777,000
Discounted balance at current discount rate	$ 493,213,000	$ 524,726,000	$ 493,213,000	$ 524,726,000
Life Insurance Segment [Member] | Oxford | Lapses actual experience
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Market Risk Benefit Measurement Input	0.0506	0.0502	0.0506	0.0502
Life Insurance Segment [Member] | Oxford | Mortality expected experience
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Market Risk Benefit Measurement Input	0.0544	0.0506	0.0544	0.0506
Life Insurance Segment [Member] | Oxford | Lapses actual experience
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Market Risk Benefit Measurement Input	0.019	0.0187	0.019	0.0187
Life Insurance Segment [Member] | Oxford | Lapses expected experience
Liability for Future Policy Benefit, after Reinsurance [Abstract]
Market Risk Benefit Measurement Input	0.0273	0.0265	0.0273	0.0265