Employee Benefit Plans (Table Text Block)	12 Months Ended
	Mar. 31, 2023
Table Text Block [Abstract]
Summary Of Financing Arrangements for Leveraged ESOP Debt	Years Ended March 31,     2023   2022     (In thousands) Allocated shares - Voting Common Stock   836   890 Allocated shares - Non-Voting Common Stock  7,821   –
Shares Held by the ESOP Plan	The components of net periodic post retirement benefit cost were as follows:     Years Ended March 31,     2023   2022   2021     (In thousands) Service cost for benefits earned during the period $ 1,326 $ 1,401 $ 1,267 Other components of net periodic benefit costs:             Interest cost on accumulated postretirement benefit   1,148   908   919 Other components   68   212   68 Total other components of net periodic benefit costs   1,216   1,120   987 Net periodic postretirement benefit cost$ 2,542 $ 2,521 $ 2,254
Components of Net Periodic Post Retirement Benefit Cost	Years Ended March 31,     2023   2022     (In thousands) Beginning of year $ 30,206 $ 30,755 Service cost for benefits earned during the period   1,326   1,401 Interest cost on accumulated post retirement benefit   1,148   908 Net benefit payments and expense   (1,207)   (1,021) Actuarial gain   (2,703)   (1,837) Accumulated postretirement benefit obligation   28,770   30,206           Current liabilities   1,625   1,449 Non-current liabilities   27,145   28,757           Total post retirement benefit liability recognized in statement of financial position   28,770   30,206 Components included in accumulated other comprehensive income (loss):         Unrecognized net loss   (465)   (3,237) Cumulative net periodic benefit cost (in excess of employer contribution)$ 28,305 $ 26,969
Components of Post Retirement Benefit Liabilities	Years Ended March 31,     2023 2022 2021     (In percentages)   Accumulated postretirement benefit obligation  5.08 % 3.76 % 2.93 %
Discount Rate Assumptions for Accumulated Postretirement Benefit Obligations	Future Net Benefit Payments     (In thousands) Year-ended:     2024 $ 1,546 2025   1,768 2026   2,021 2027   2,270 2028   2,532 2029 Through 2033   13,291 Total$ 23,428