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