Fair Value Measurements (Table Text Block)	9 Months Ended	12 Months Ended
	Dec. 31, 2020	Mar. 31, 2020
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, 2020   Value   Level 1   Level 2   Level 3   Fair Value     (Unaudited) Assets   (In thousands) Reinsurance recoverables and trade receivables, net $ 224,447 $ - $ - $ 224,447 $ 224,447 Mortgage loans, net   350,210   -   -   350,210   350,210 Other investments   97,692   -   -   97,692   97,692 Total $ 672,349 $ - $ - $ 672,349 $ 672,349                                             Liabilities                     Notes, loans and finance/capital leases payable   4,678,227   -   4,678,227   -   4,452,716 Total $ 4,678,227 $ - $ 4,678,227 $ - $ 4,452,716	Fair Value Hierarchy     Carrying               Total Estimated As of March 31, 2020   Value   Level 1   Level 2   Level 3   Fair Value     (In thousands) Assets                     Reinsurance recoverables and trade receivables, net $ 186,672 $ - $ - $ 186,672 $ 186,672 Mortgage loans, net   262,688   -   -   262,688   262,688 Other investments   97,685   -   -   97,685   97,685 Total $ 547,045 $ - $ - $ 547,045 $ 547,045                                             Liabilities                     Notes, loans and finance/capital leases payable   4,651,068   -   4,651,068   -   4,342,308 Total $ 4,651,068 $ - $ 4,651,068 $ - $ 4,342,308
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis	As of December 31, 2020   Total   Level 1   Level 2   Level 3     (Unaudited) Assets   (In thousands) Short-term investments $ 1,128,967 $ 1,128,667 $ 300 $ - Fixed maturities - available for sale   2,565,293   7,602   2,557,532   159 Preferred stock   22,215   22,215   -   - Common stock   19,445   19,445   -   - Derivatives   5,797   5,797   -   - Total $ 3,741,717 $ 1,183,726 $ 2,557,832 $ 159                                     Liabilities                 Derivatives   6,158   -   6,158   - Total $ 6,158 $ - $ 6,158 $ -	As of March 31, 2020   Total   Level 1   Level 2   Level 3     (In thousands) Assets                 Short-term investments $ 369,279 $ 368,968 $ 311 $ - Fixed maturities - available for sale   2,466,048   7,156   2,458,731   161 Preferred stock   6,675   6,675   -   - Common stock   20,015   20,015   -   - Derivatives   5,944   5,944   -   - Total $ 2,867,961 $ 408,758 $ 2,459,042 $ 161                                     Liabilities                 Derivatives   8,214   -   8,214   - Total $ 8,214 $ - $ 8,214 $ -