Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2019	Jul. 31, 2018
Cash flows from operating activities:
Net income	$ 85,815	$ 70,224
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	59,808	58,840
Stock-based compensation	7,542	10,272
Loss on disposal of assets and impairment charges	527	345
Deferred income taxes	17,052	9,205
Changes in assets and liabilities:
Receivables	(1,698)	(1,441)
Inventories	(474)	(22,211)
Prepaid expenses	(5,476)	(3,174)
Accounts payable	3,610	9,588
Accrued expenses	(3,699)	12,281
Income taxes	15,054	8,901
Other, net	696	(2,759)
Net cash provided by operating activities	178,757	150,071
Cash flows from investing activities:
Purchase of property and equipment	(101,398)	(97,490)
Payments for acquisition of businesses, net of cash acquired	(4,868)	(841)
Proceeds from sales of property and equipment	1,699	1,879
Net cash used in investing activities	(104,567)	(96,452)
Cash flows from financing activities:
Repayments of long-term debt	(905)	(92)
Net repayments of short-term debt	(25,000)	(12,189)
Proceeds from exercise of stock options	2,261	148
Payments of cash dividends	(10,633)	(9,592)
Repurchase of common stock	0	(37,479)
Tax withholdings on employee share-based awards	(6,476)	(3,252)
Net cash used in financing activities	(40,753)	(62,456)
Net increase (decrease) in cash and cash equivalents	33,437	(8,837)
Cash and cash equivalents at beginning of the period	63,296	53,679
Cash and cash equivalents at end of the period	96,733	44,842
Cash paid (received) during the period for:
Interest, net of amount capitalized	6,837	5,205
Income taxes, net	(6,401)	397
Noncash investing and financing activities:
Purchased property and equipment in accounts payable	$ 23,947	4,524
Noncash additions from adoption of ASC 842		$ 22,635