Financial Information by Geographic Area (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Fiscal year ended:
Total revenues	$ 5,739,747	$ 4,541,985	$ 3,978,868
Depreciation and amortization, net of (gains) losses on disposals	512,486	641,504	667,524
Interest expense	167,424	163,502	160,950
Pretax earnings	1,475,497	796,658	378,124
Income tax expense	352,211	185,802	(63,924)
Identifiable assets	17,299,581	14,651,606	13,438,024
United States [Member]
Fiscal year ended:
Total revenues	5,452,027	4,334,083	3,797,849
Depreciation and amortization, net of (gains) losses on disposals	509,517	631,344	652,110
Interest expense	163,586	160,429	157,595
Pretax earnings	1,431,155	773,030	372,687
Income tax expense	342,213	180,845	(65,842)
Identifiable assets	16,776,070	14,212,978	13,016,942
Canada [Member]
Fiscal year ended:
Total revenues	287,720	207,902	181,019
Depreciation and amortization, net of (gains) losses on disposals	2,969	10,160	15,414
Interest expense	3,838	3,073	3,355
Pretax earnings	44,342	23,628	5,437
Income tax expense	9,998	4,957	1,918
Identifiable assets	$ 523,511	$ 438,628	$ 421,082