Employee Benefit Plans (Table Text Block)	12 Months Ended
	Mar. 31, 2020
Table Text Block [Abstract]
Summary Of Financing Arrangements for Leveraged ESOP Debt	Outstanding as of   Interest Payments Financing Date   March 31, 2020   2020   2019   2018     (In thousands) June, 1991 $ – $ – $ 1 $ 1 July, 2009   –   9   17   26 February, 2016   –   229   190   242
Shares Held by the ESOP Plan	Years Ended March 31,     2020   2019     (In thousands) Allocated shares   1,003   1,069 Unreleased shares - leveraged   –   16 Fair value of unreleased shares - leveraged $ – $ 6,019 Unreleased shares - non-leveraged   –   – Fair value of unreleased shares - non-leveraged $ – $ –
Components of Net Periodic Post Retirement Benefit Cost	Years Ended March 31,     2020   2019   2018     (In thousands) Service cost for benefits earned during the period $ 1,055 $ 1,108 $ 1,073 Other components of net periodic benefit costs:             Interest cost on accumulated postretirement benefit   964   943   869 Other components   90   70   58 Total other components of net periodic benefit costs   1,054   1,013   927 Net periodic postretirement benefit cost $ 2,109 $ 2,121 $ 2,000
Components of Post Retirement Benefit Liabilities	Years Ended March 31,     2020   2019     (In thousands) Beginning of year $ 25,817 $ 23,316 Service cost for benefits earned during the period   1,055   1,108 Interest cost on accumulated post retirement benefit   964   943 Net benefit payments and expense   (93)   (979) Actuarial (gain) loss   (240)   1,429 Accumulated postretirement benefit obligation   27,503   25,817           Current liabilities   1,151   1,037 Non-current liabilities   26,352   24,780           Total post retirement benefit liability recognized in statement of financial position   27,503   25,817 Components included in accumulated other comprehensive income (loss):         Unrecognized net loss   (3,447)   (3,890) Cumulative net periodic benefit cost (in excess of employer contribution) $ 24,056 $ 21,927
Discount Rate Assumptions for Accumulated Postretirement Benefit Obligations	Years Ended March 31,     2020 2019 2018     (In percentages)   Accumulated postretirement benefit obligation   3.37 % 3.83 % 3.98 %
Future Net Benefit Payments Expected for Post Employee Benefit Obligations	Future Net Benefit Payments     (In thousands) Year-ended:     2021 $ 1,151 2022   1,350 2023   1,547 2024   1,753 2025   1,965 2026 through 2029   11,581 Total $ 19,347