Provision for Taxes (Earnings Before Taxes and Provision for Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022
Pretax earnings:
U.S.	$ 816,238	$ 1,179,738	$ 1,432,231
Non-U.S.	23,939	39,659	44,342
Total pretax earnings	840,177	1,219,397	1,476,573
Current provision (benefit)
Federal	66,356	115,171	189,488
State	44,707	42,121	55,518
Non-U.S.	254	5,150	6,893
Current provision (benefit), total	111,317	162,442	251,899
Deferred provision (benefit)
Federal	88,549	114,355	90,852
State	6,542	14,077	6,355
Non-U.S.	5,062	4,051	3,105
Deferred Income Tax Expense (Benefit), Total	100,153	132,483	100,312
Provision for income tax expense	211,470	294,925	352,211
Income taxes paid (received)	$ 68,623	$ 145,680	$ 4,548