Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 512,384	$ 89,593	$ (42,758)
Other comprehensive income (loss):
Foreign currency translation adjustment	5,057	(1,273)	(5,772)
Amounts arising during the period - net of tax expense
Prior service credit, net of taxes of $0, $0, $0, and $0, respectively			2,902
Actuarial gain (loss), net of taxes of $0, $0, and $0, respectively	12,511	(113,232)	41,756
Reclassification to net income (loss) - net of tax expense
Amortization of net loss, net of taxes of $0, $0, and $0, respectively	26,159	26,728	34,082
Recognized prior service credits, net of taxes of $0, $0, and $0, respectively	(5,002)	(5,002)	(4,845)
Total defined benefit pension plans and other postretirement benefits income (expense), net of taxes	33,668	(91,506)	73,895
Cash flow hedges:
Unrealized gain (loss) arising during the period, net of tax expense of $0, $0, and $0, respectively	796	2,265	(2,244)
Reclassification of (gain) loss included in net earnings, net of tax expense of $0, $0, and $0, respectively	(1,944)	(778)	959
Net unrealized (loss) gain on cash flow hedges, net of tax	(1,148)	1,487	(1,285)
Total other comprehensive income (loss)	37,577	(91,292)	66,838
Total comprehensive income (loss)	$ 549,961	$ (1,699)	$ 24,080