Fair Value Measurements (Carrying and Estimated Fair Values within Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Mar. 31, 2019
Assets
Reinsurance recoverables and trade receivables, net	$ 200,164	$ 224,785
Mortgage loans, net	259,867	225,829
Other investments	76,860	74,907
Total	536,891	525,521
Liabilities
Notes, loans and leases payable, gross		4,192,243
Total	4,548,609	4,192,243
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	4,548,609	4,192,243
Total	4,548,609	4,192,243
Level 3 [Member]
Assets
Reinsurance recoverables and trade receivables, net	200,164	224,785
Mortgage loans, net	259,867	225,829
Other investments	76,860	74,907
Total	536,891	525,521
Liabilities
Notes, loans and leases payable, gross	0	0
Total	0	0
Carrying Value [Member]
Assets
Reinsurance recoverables and trade receivables, net	200,164	224,785
Mortgage loans, net	259,867	225,829
Other investments	76,860	74,907
Total	536,891	525,521
Liabilities
Notes, loans and leases payable, gross	4,548,609	4,192,243
Total	$ 4,548,609	$ 4,192,243