Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2019	Oct. 31, 2018
Cash flows from operating activities:
Net income	$ 167,796	$ 136,839
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	122,696	120,196
Stock-based compensation	9,922	9,323
Loss on disposal of assets and impairment charges	1,257	1,130
Deferred income taxes	31,483	34,214
Changes in assets and liabilities:
Receivables	(6,919)	(1,830)
Inventories	1,912	(16,923)
Prepaid expenses	(6,290)	(2,157)
Accounts payable	(9,577)	2,030
Accrued expenses	(8,706)	(3,330)
Income taxes	9,475	35,160
Other, net	(1,640)	(10,363)
Net cash provided by operating activities	311,409	304,289
Cash flows from investing activities:
Purchase of property and equipment	(242,173)	(198,409)
Payments for acquisition of businesses, net of cash acquired	(6,191)	(2,590)
Proceeds from sales of property and equipment	2,940	3,155
Net cash used in investing activities	(245,424)	(197,844)
Cash flows from financing activities:
Repayments of long-term debt	(8,682)	(7,743)
Net repayments of short-term debt	(50,000)	(39,600)
Proceeds from exercise of stock options	2,307	379
Payments of cash dividends	(22,405)	(20,193)
Repurchase of common stock	0	(37,479)
Tax withholdings on employee share-based awards	(6,525)	(3,601)
Net cash used in financing activities	(85,305)	(108,237)
Net decrease in cash and cash equivalents	(19,320)	(1,792)
Cash and cash equivalents at beginning of the period	63,296	53,679
Cash and cash equivalents at end of the period	43,976	51,887
Cash paid (received) during the period for:
Interest, net of amount capitalized	26,997	24,256
Income taxes, net	10,000	(27,477)
Noncash investing and financing activities:
Purchased property and equipment in accounts payable	$ 17,067	3,589
Noncash additions from adoption of ASC 842		$ 22,635