Fair Value Measurements (Table Text Block)	3 Months Ended	12 Months Ended
	Jun. 30, 2023	Mar. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Abstract]
Financial Instruments, Carrying and Estimated fair values	Fair Value Hierarchy     Carrying               Total Estimated As of June 30, 2023   Value   Level 1   Level 2   Level 3   Fair Value     (Unaudited) Assets   (In thousands) Reinsurance recoverables and trade receivables, net $ 206,663 $ – $ – $ 206,663 $ 206,663 Mortgage loans, net   510,307   –   –   494,664   494,664 Other investments   109,833   –   –   109,833   109,833 Total $ 826,803 $ – $ – $ 811,160 $ 811,160                                             Liabilities                     Notes, loans and finance leases payable   6,323,782   –   5,743,138   –   5,743,138 Total$ 6,323,782 $ – $ 5,743,138 $ – $ 5,743,138	Fair Value Hierarchy     Carrying               Total Estimated As of March 31, 2023   Value   Level 1   Level 2   Level 3   Fair Value     (In thousands) Assets                     Reinsurance recoverables and trade receivables, net $ 189,498 $ – $ – $ 189,498 $ 189,498 Mortgage loans, net   466,531   –   –   444,957   444,957 Other investments   109,009   –   –   109,009   109,009 Total $ 765,038 $ – $ – $ 743,464 $ 743,464                                             Liabilities                     Notes, loans and finance leases payable   6,143,350   –   5,710,735   –   5,710,735 Total$ 6,143,350 $ – $ 5,710,735 $ – $ 5,710,735
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	As of June 30, 2023   Total   Level 1   Level 2   Level 3     (Unaudited) Assets   (In thousands) Short-term investments $ 2,055,145 $ 2,053,510 $ 1,635 $ – Fixed maturities - available for sale   2,407,226   24,549   2,382,618   59 Preferred stock   20,556   20,556   –   – Common stock   41,730   41,730   –   – Derivatives   16,793   7,539   9,254   – Total$ 4,541,450 $ 2,147,884 $ 2,393,507 $ 59	As of March 31, 2023   Total   Level 1   Level 2   Level 3     (In thousands) Assets                 Short-term investments $ 1,809,441 $ 1,808,797 $ 644 $ – Fixed maturities - available for sale   2,709,037   251,832   2,457,146   59 Preferred stock   21,982   21,982   –   – Common stock   39,375   39,375   –   – Derivatives   9,606   4,295   5,311   – Total$ 4,589,441 $ 2,126,281 $ 2,463,101 $ 59