Fair Value Measurements (Financial instruments level within the fair value hierarchy) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Mar. 31, 2024
Assets:
Fixed maturities - available for sale	$ 2,617,126	$ 2,442,504
Preferred stock	22,871	21,260
Common stock	44,796	45,014
Derivatives	14,631	18,930
Total	2,518,938	2,527,708
Liabilities:
Derivatives	713
Guaranteed residual values of TRAC leases	8,912	9,300
Liabilities from investment contracts	2,495,885	2,290,096
Market risk benefits	13,428	13,400
Total	2,699,424	2,312,796
Level 1 [Member]
Assets:
Preferred stock	22,871	21,260
Common stock	44,796	45,014
Derivatives	8,333	10,538
Total		76,812
Liabilities:
Total	76,000
Level 2 [Member]
Assets:
Fixed maturities - available for sale	2,617,126	2,442,446
Derivatives	6,298	8,392
Total		2,450,838
Liabilities:
Derivatives	713
Total	2,623,424
Level 3 [Member]
Assets:
Fixed maturities - available for sale		58
Total	2,518,225	58
Liabilities:
Guaranteed residual values of TRAC leases	8,912	9,300
Liabilities from investment contracts	2,495,885	2,290,096
Market risk benefits	$ 13,428	13,400
Total		$ 2,312,796