Employee Benefit Plans (Table Text Block)	12 Months Ended
	Mar. 31, 2021
Table Text Block [Abstract]
Summary Of Financing Arrangements for Leveraged ESOP Debt	Outstanding as of   Interest Payments Financing Date   March 31, 2021   2021   2020   2019     (In thousands) June, 1991 $ - $ - $ - $ 1 July, 2009   -   -   9   17 February, 2016   -   -   229   190
Shares Held by the ESOP Plan	Years Ended March 31,     2021   2020     (In thousands) Allocated shares   951   1,003 Unreleased shares - leveraged   -   - Fair value of unreleased shares - leveraged $ - $ - Unreleased shares - non-leveraged   -   - Fair value of unreleased shares - non-leveraged $ - $ -
Components of Net Periodic Post Retirement Benefit Cost	Years Ended March 31,     2021   2020   2019     (In thousands) Service cost for benefits earned during the period $ 1,267 $ 1,055 $ 1,108 Other components of net periodic benefit costs:             Interest cost on accumulated postretirement benefit   919   964   943 Other components   68   90   70 Total other components of net periodic benefit costs   987   1,054   1,013 Net periodic postretirement benefit cost $ 2,254 $ 2,109 $ 2,121
Components of Post Retirement Benefit Liabilities	Years Ended March 31,     2021   2020     (In thousands) Beginning of year $ 27,503 $ 25,817 Service cost for benefits earned during the period   1,267   1,055 Interest cost on accumulated post retirement benefit   919   964 Net benefit payments and expense   (841)   (93) Actuarial (gain) loss   1,907   (240) Accumulated postretirement benefit obligation   30,755   27,503           Current liabilities   1,334   1,151 Non-current liabilities   29,421   26,352           Total post retirement benefit liability recognized in statement of financial position   30,755   27,503 Components included in accumulated other comprehensive income (loss):         Unrecognized net loss   (5,286)   (3,447) Cumulative net periodic benefit cost (in excess of employer contribution) $ 25,469 $ 24,056
Discount Rate Assumptions for Accumulated Postretirement Benefit Obligations	Years Ended March 31,     2021 2020 2019     (In percentages)   Accumulated postretirement benefit obligation   2.93 % 3.37 % 3.83 %
Future Net Benefit Payments Expected for Post Employee Benefit Obligations	Future Net Benefit Payments     (In thousands) Year-ended:     2022 $ 1,334 2023   1,520 2024   1,719 2025   1,937 2026   2,167 2027 through 2030   12,529 Total $ 21,206