Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2020	Oct. 31, 2019
Cash flows from operating activities:
Net income	$ 232,575	$ 167,796
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	130,114	122,696
Share-based compensation	14,492	9,922
Loss on disposal of assets and impairment charges	2,159	1,257
Deferred income taxes	15,607	31,483
Changes in assets and liabilities:
Receivables	(7,609)	(6,919)
Inventories	(13,835)	1,912
Prepaid expenses	(8,381)	(6,290)
Accounts payable	125,719	(9,577)
Accrued expenses	39,177	(8,706)
Income taxes	22,924	9,475
Other, net	(985)	(1,640)
Net cash provided by operating activities	551,957	311,409
Cash flows from investing activities:
Purchase of property and equipment	(158,815)	(242,173)
Payments for acquisition of businesses, net of cash acquired	0	(6,191)
Proceeds from sales of property and equipment	2,667	2,940
Net cash used in investing activities	(156,148)	(245,424)
Cash flows from financing activities:
Proceeds from long-term debt	650,000	0
Repayments of long-term debt	(570,738)	(8,682)
Net payments of short-term debt	(120,000)	(50,000)
Proceeds from exercise of stock options	1,253	2,307
Proceeds from capital grant	1,594	0
Payments of cash dividends	(23,591)	(22,405)
Tax withholdings on employee share-based awards	(7,917)	(6,525)
Net cash used in financing activities	(69,399)	(85,305)
Net increase (decrease) in cash and cash equivalents	326,410	(19,320)
Cash and cash equivalents at beginning of the period	78,275	63,296
Cash and cash equivalents at end of the period	404,685	43,976
Cash paid during the period for:
Interest, net of amount capitalized	26,535	26,997
Income taxes, net	31,956	10,000
Noncash investing and financing activities:
Purchased property and equipment in accounts payable	18,471	17,067
Right-of-use assets obtained in exchange for new finance lease liabilities	0	831
Right-of-use assets obtained in exchange for new operating lease liabilities	1,109	0
Noncash additions from adoption of ASC 842	$ 0	$ 22,635