Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Cash flows from operating activities:
Net income	$ 61,806	$ 50,097
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	39,399	36,249
Other amortization	110	108
Stock based compensation	1,737	1,632
(Gain) loss on disposal of assets and impairment charges	(259)	242
Deferred income taxes	(1,617)	4,037
Excess tax benefits related to stock option exercises	(1,140)	(579)
Changes in assets and liabilities:
Receivables	(11,045)	(4,490)
Inventories	(17,998)	(11,362)
Prepaid expenses	(2,598)	(1,270)
Accounts payable	3,402	4,960
Accrued expenses	3,120	10,969
Income taxes	26,986	25,782
Other, net	(107)	(18)
Net cash provided by operating activities	101,796	116,357
Cash flows from investing activities:
Purchase of property and equipment	(100,141)	(88,789)
Payments for acquisition of businesses, net of cash acquired	0	(30,774)
Proceeds from sales of property and equipment	1,288	557
Net cash used in investing activities	(98,853)	(119,006)
Cash flows from financing activities:
Repayments of long-term debt	(98)	(223)
Proceeds from exercise of stock options	1,805	4,313
Payments of cash dividends	(7,726)	(6,914)
Excess tax benefits related to stock option exercises	1,140	579
Net cash used in financing activities	(4,879)	(2,245)
Net decrease in cash and cash equivalents	(1,936)	(4,894)
Cash and cash equivalents at beginning of the period	48,541	121,641
Cash and cash equivalents at end of the period	46,605	116,747
Cash paid (received) during the period for:
Interest, net of amount capitalized	3,471	3,665
Income taxes, net	10,749	(106)
Noncash investing and financing activities:
Purchased property and equipment in accounts payable	$ 13,203	$ 0