Life Insurance Liability (Sensitive Life Insurance Type Products) (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2024 USD ($)	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	$ 256,175	$ 223,958	$ 167,424
Life Insurance Segment [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Gross premiums	$ 52,909	$ 56,563
Expected future lifetime (persistency) of policies in force (years)	6 years 9 months 18 days	7 years
Weighted average original interest rate of the liability for future policy benefits	4.99%	5.03%
Weighted average current interest rate of the liability for future policy benefits	5.03%	0.56%
Life Insurance Segment [Member] | Oxford
Liability for Future Policy Benefit, Activity [Line Items]
Interest expense	$ 15,322	$ 15,441
Expected gross premiums: | Life Insurance Segment [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted balance	367,640	405,017
Discounted balance at original discount rate	285,087	311,988
Discounted balance at current discount rate	286,295	308,822
Expected policy benefits: | Life Insurance Segment [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Undiscounted balance	742,927	779,778
Discounted balance at original discount rate	514,112	533,688
Discounted balance at current discount rate	$ 522,121	$ 530,983
Lapses actual experience | Life Insurance Segment [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Market Risk Benefit, Measurement Input	0.0449	0.0467
Mortality expected experience | Life Insurance Segment [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Market Risk Benefit, Measurement Input	0.0506	0.048
Lapses actual experience | Life Insurance Segment [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Market Risk Benefit, Measurement Input	0.021	0.0204
Lapses expected experience | Life Insurance Segment [Member]
Liability for Future Policy Benefit, Activity [Line Items]
Market Risk Benefit, Measurement Input	0.0263	0.0252