Employee Benefit Plans (Table Text Block)	12 Months Ended
	Mar. 31, 2022
Table Text Block [Abstract]
Summary Of Financing Arrangements for Leveraged ESOP Debt	Outstanding as of   Interest Payments Financing Date   March 31, 2022   2022   2021   2020     (In thousands) July, 2009   –   –   –   9 February, 2016  –   –   –   229
Shares Held by the ESOP Plan	Years Ended March 31,     2022   2021     (In thousands) Allocated shares   890   951 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,     2022   2021   2020     (In thousands) Service cost for benefits earned during the period $ 1,401 $ 1,267 $ 1,055 Other components of net periodic benefit costs:             Interest cost on accumulated postretirement benefit   908   919   964 Other components   212   68   90 Total other components of net periodic benefit costs   1,120   987   1,054 Net periodic postretirement benefit cost$ 2,521 $ 2,254 $ 2,109
Components of Post Retirement Benefit Liabilities	Years Ended March 31,     2022   2021     (In thousands) Beginning of year $ 30,755 $ 27,503 Service cost for benefits earned during the period   1,401   1,267 Interest cost on accumulated post retirement benefit   908   919 Net benefit payments and expense   (1,021)   (841) Actuarial (gain) loss   (1,837)   1,907 Accumulated postretirement benefit obligation   30,206   30,755           Current liabilities   1,449   1,334 Non-current liabilities   28,757   29,421           Total post retirement benefit liability recognized in statement of financial position   30,206   30,755 Components included in accumulated other comprehensive income (loss):         Unrecognized net loss   (3,237)   (5,286) Cumulative net periodic benefit cost (in excess of employer contribution)$ 26,969 $ 25,469
Discount Rate Assumptions for Accumulated Postretirement Benefit Obligations	Years Ended March 31,     2022 2021 2020     (In percentages)   Accumulated postretirement benefit obligation  3.76 % 2.93 % 3.37 %
Future Net Benefit Payments Expected for Post Employee Benefit Obligations	Future Net Benefit Payments     (In thousands) Year-ended:     2023 $ 1,369 2024   1,536 2025   1,733 2026   1,950 2027   2,170 2028 Through 2032   12,112 Total$ 20,870