Industry Segment and Geographic Area Data (Details) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Mar. 31, 2023
Quarter ended:
Total revenues	$ 1,540,308	$ 1,597,840
Depreciation and amortization, net of (gains) losses on disposals	146,880	123,775
Interest expense	60,598	49,799
Pretax earnings (loss)	338,695	445,399
Income tax expense	81,857	107,054
Identifiable assets	18,614,034	17,793,811	$ 18,100,734
United States [Member]
Quarter ended:
Total revenues	1,461,284	1,510,386
Depreciation and amortization, net of (gains) losses on disposals	148,313	120,986
Interest expense	59,946	48,948
Pretax earnings (loss)	327,072	431,881
Income tax expense	78,595	103,613
Identifiable assets	17,892,739	17,202,853
Canada [Member]
Quarter ended:
Total revenues	79,024	87,454
Depreciation and amortization, net of (gains) losses on disposals	(1,433)	2,789
Interest expense	652	851
Pretax earnings (loss)	11,623	13,518
Income tax expense	3,262	3,441
Identifiable assets	$ 721,295	$ 590,958