Fair Value Measurements (Table Text Block)	9 Months Ended	12 Months Ended
	Dec. 31, 2021	Mar. 31, 2021
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 December 31, 2021   Value   Level 1   Level 2   Level 3   Fair Value     (Unaudited) Assets   (In thousands) Reinsurance recoverables and trade receivables, net $ 230,437 $ – $ – $ 230,437 $ 230,437 Mortgage loans, net   494,790   –   –   494,790   494,790 Other investments   107,581   –   –   107,581   107,581 Total $ 832,808 $ – $ – $ 832,808 $ 832,808                                             Liabilities                     Notes, loans and finance leases payable   5,397,856   –   5,397,856   –   5,196,104 Total$ 5,397,856 $ – $ 5,397,856 $ – $ 5,196,104	Fair Value Hierarchy     Carrying               Total Estimated As of March 31, 2021   Value   Level 1   Level 2   Level 3   Fair Value     (In thousands) Assets                     Reinsurance recoverables and trade receivables, net $ 224,426 $ – $ – $ 224,426 $ 224,426 Mortgage loans, net   391,230   –   –   391,230   391,230 Other investments   98,529   –   –   98,529   98,529 Total $ 714,185 $ – $ – $ 714,185 $ 714,185                                             Liabilities                     Notes, loans and finance leases payable   4,698,615   –   4,698,615   –   4,449,691 Total$ 4,698,615 $ – $ 4,698,615 $ – $ 4,449,691
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	As of December 31, 2021   Total   Level 1   Level 2   Level 3     (Unaudited) Assets   (In thousands) Short-term investments $ 2,102,275 $ 2,102,275 $ – $ – Fixed maturities - available for sale   2,743,151   17,103   2,725,938   110 Preferred stock   28,112   28,112   –   – Common stock   24,179   24,179   –   – Derivatives   6,557   6,557   –   – Total $ 4,904,274 $ 2,178,226 $ 2,725,938 $ 110                                     Liabilities                 Derivatives   2,051   –   2,051   – Total$ 2,051 $ – $ 2,051 $ –	As of March 31, 2021   Total   Level 1   Level 2   Level 3     (In thousands) Assets                 Short-term investments $ 839,250 $ 839,250 $ – $ – Fixed maturities - available for sale   2,653,539   6,967   2,646,415   157 Preferred stock   21,677   21,677   –   – Common stock   20,440   20,440   –   – Derivatives   6,601   6,601   –   – Total $ 3,541,507 $ 894,935 $ 2,646,415 $ 157                                     Liabilities                 Derivatives   5,141   –   5,141   – Total$ 5,141 $ – $ 5,141 $ –