Pension and Other Postretirement Benefit Plans - Schedule of Components of Net Periodic Benefit Costs (Income) (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 192	$ 377
Interest cost	11,823	16,087
Expected return on plan assets	(33,455)	(34,105)
Amortization of prior service credits	42	243
Amortization of net loss	9,583	7,798
Curtailment loss	16,024
Special termination benefits	54
Net periodic benefit cost (income)	4,263	$ (9,600)
Other postretirement [Member]
Defined Benefit Plan Disclosure [Line Items]
Net periodic benefit cost (income)	$ 2,349