Fair Value Measurements (Carrying and Estimated Fair Values within Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Mar. 31, 2023
Assets
Reinsurance recoverables and trade receivables, net	$ 212,565	$ 189,498
Mortgage loans, net	521,831	444,957
Other investments	88,712	109,009
Total	823,108	743,464
Liabilities
Notes, loans and leases payable, gross	5,961,511	5,710,735
Total	5,961,511	5,710,735
Level 1 [Member]
Assets
Reinsurance recoverables and trade receivables, net	0	0
Mortgage loans, net	0	0
Other investments	0	0
Total	0	0
Liabilities
Notes, loans and leases payable, gross	0	0
Total	0	0
Level 2 [Member]
Assets
Reinsurance recoverables and trade receivables, net	0	0
Mortgage loans, net	0	0
Other investments	0	0
Total	0	0
Liabilities
Notes, loans and leases payable, gross	5,961,511	5,710,735
Total	5,961,511	5,710,735
Level 3 [Member]
Assets
Reinsurance recoverables and trade receivables, net	212,565	189,498
Mortgage loans, net	521,831	444,957
Other investments	88,712	109,009
Total	823,108	743,464
Liabilities
Notes, loans and leases payable, gross	0	0
Total	0	0
Carrying Value [Member]
Assets
Reinsurance recoverables and trade receivables, net	212,565	189,498
Mortgage loans, net	550,913	466,531
Other investments	88,712	109,009
Total	852,190	765,038
Liabilities
Notes, loans and leases payable, gross	6,436,800	6,143,350
Total	$ 6,436,800	$ 6,143,350