Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Oct. 31, 2018	Oct. 31, 2017
Cash flows from operating activities:
Net income	$ 136,839	$ 105,676
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	120,196	106,526
Stock-based compensation	9,323	13,700
Loss on disposal of assets and impairment charges	1,130	1,091
Deferred income taxes	34,214	21,543
Changes in assets and liabilities:
Receivables	(1,830)	746
Inventories	(16,923)	(39,035)
Prepaid expenses	(2,157)	2,412
Accounts payable	2,030	69
Accrued expenses	(3,330)	8,907
Income taxes	35,160	20,604
Other, net	(10,363)	(676)
Net cash provided by operating activities	304,289	241,563
Cash flows from investing activities:
Purchase of property and equipment	(198,409)	(248,797)
Payments for acquisition of businesses, net of cash acquired	(2,590)	(22,781)
Proceeds from sales of property and equipment	3,155	2,297
Net cash used in investing activities	(197,844)	(269,281)
Cash flows from financing activities:
Proceeds from long-term debt	0	400,000
Repayments of long-term debt	(7,743)	(7,708)
Net repayments of short-term debt	(39,600)	(900)
Proceeds from exercise of stock options	379	298
Payments of cash dividends	(20,193)	(19,235)
Repurchase of common stock	(37,479)	(132,613)
Tax withholdings on employee share-based awards	(3,601)	(3,656)
Net cash (used in) provided by financing activities	(108,237)	236,186
Net (decrease) increase in cash and cash equivalents	(1,792)	208,468
Cash and cash equivalents at beginning of the period	53,679	76,717
Cash and cash equivalents at end of the period	51,887	285,185
Cash paid (received) during the period for:
Interest, net of amount capitalized	24,256	21,428
Income taxes, net	(27,477)	21,414
Noncash investing and financing activities:
Purchased property and equipment in accounts payable	3,589	12,563
Shares repurchased in accounts payable	$ 0	$ 575