Financial Information by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Fiscal year ended:
Total revenues	$ 5,625,674	$ 5,864,691	$ 5,739,747
Depreciation and amortization, net of gains on disposal	696,083	520,315	512,486
Interest expense	256,175	223,958	167,424
Pretax earnings	840,177	1,219,397	1,476,573
Income tax expense	211,470	294,925	352,211
Identifiable assets	19,058,758	18,100,734	17,327,183	$ 14,651,606	$ 14,693,044
United States [Member]
Fiscal year ended:
Total revenues	5,337,502	5,570,264	5,452,027
Depreciation and amortization, net of gains on disposal	690,429	514,043	509,517
Interest expense	253,388	221,008	163,586
Pretax earnings	816,238	1,179,738	1,432,231
Income tax expense	206,154	285,724	342,213
Identifiable assets	18,256,637	17,429,101	16,803,672
Canada [Member]
Fiscal year ended:
Total revenues	288,172	294,427	287,720
Depreciation and amortization, net of gains on disposal	5,654	6,272	2,969
Interest expense	2,787	2,950	3,838
Pretax earnings	23,939	39,659	44,342
Income tax expense	5,316	9,201	9,998
Identifiable assets	$ 802,121	$ 671,633	$ 523,511