Fair Value Measurements (Table Text Block)	9 Months Ended	12 Months Ended
	Dec. 31, 2019	Mar. 31, 2019
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, 2019   Value   Level 1   Level 2   Level 3   Fair Value     (Unaudited) Assets   (In thousands) Reinsurance recoverables and trade receivables, net $ 200,164 $ – $ – $ 200,164 $ 200,164 Mortgage loans, net   259,867   –   –   259,867   259,867 Other investments   76,860   –   –   76,860   76,860 Total $ 536,891 $ – $ – $ 536,891 $ 536,891                                             Liabilities                     Notes, loans and finance/capital leases payable   4,548,609   –   4,548,609   –   4,548,609 Total $ 4,548,609 $ – $ 4,548,609 $ – $ 4,548,609	Fair Value Hierarchy     Carrying               Total Estimated As of March 31, 2019   Value   Level 1   Level 2   Level 3   Fair Value     (In thousands) Assets                     Reinsurance recoverables and trade receivables, net $ 224,785 $ – $ – $ 224,785 $ 224,785 Mortgage loans, net   225,829   –   –   225,829   225,829 Other investments   74,907   –   –   74,907   74,907 Total $ 525,521 $ – $ – $ 525,521 $ 525,521                                             Liabilities                     Notes, loans and leases payable   4,192,243   –   4,192,243   –   4,192,243 Total $ 4,192,243 $ – $ 4,192,243 $ – $ 4,192,243
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	As of December 31, 2019   Total   Level 1   Level 2   Level 3     (Unaudited) Assets   (In thousands) Short-term investments $ 476,776 $ 476,776 $ – $ – Fixed maturities - available for sale   2,440,404   7,607   2,432,578   219 Preferred stock   9,076   9,076   –   – Common stock   19,988   19,988   –   – Derivatives   4,795   4,795   –   – Total $ 2,951,039 $ 518,242 $ 2,432,578 $ 219                                     Liabilities                 Derivatives   1,415   –   1,415   – Total $ 1,415 $ – $ 1,415 $ –	As of March 31, 2019   Total   Level 1   Level 2   Level 3     (In thousands) Assets                 Short-term investments $ 463,847 $ 463,599 $ 248 $ – Fixed maturities - available for sale   2,209,761   7,327   2,202,213   221 Preferred stock   8,257   8,257   –   – Common stock   17,379   17,379   –   – Derivatives   1,607   1,468   139   – Total $ 2,700,851 $ 498,030 $ 2,202,600 $ 221                                     Liabilities                 Derivatives   –   –   –   – Total $ – $ – $ – $ –