Benefit Plans (Amortize pre-tax amount AOCI) (Details)
$ in Thousands
12 Months Ended
Mar. 31, 2020
USD ($)
Defined Benefit Plan Disclosure [Line Items]  
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, before Tax $ 14,405
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax 7,463
Other Pension Plans, Defined Benefit [Member]  
Defined Benefit Plan Disclosure [Line Items]  
Defined Benefit Plan, Amortization of Prior Service Cost (Credit) $ (3,263)