Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2014	May 31, 2013	May 31, 2012
Operating activities:
Net earnings	$ 160,152	$ 136,835	$ 125,353
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	79,730	66,469	55,873
Impairment of long-lived assets	58,246	6,488	355
Provision for deferred income taxes	(25,916)	1,798	775
Bad debt expense	32	783	339
Equity in net income of unconsolidated affiliates, net of distributions	(15,333)	(10,948)	(1,019)
Net loss (gain) on sale of assets	(11,212)	1,121	(5,918)
Stock-based compensation	22,017	13,270	11,742
Excess tax benefits - stock-based compensation	(8,880)	(5,183)	(578)
Gain on previously held equity interest in TWB	(11,000)
Changes in assets and liabilities, net of impact of acquisitions:
Receivables	(49,206)	18,801	956
Inventories	(38,010)	77,115	17,310
Prepaid expenses and other current assets	(2,921)	871	8,478
Other assets	(5,278)	4,636	4,141
Accounts payable and accrued expenses	69,682	(47,483)	(45,847)
Other liabilities	6,943	8,404	1,689
Net cash provided by operating activities	229,046	272,977	173,649
Investing activities:
Investment in property, plant and equipment	(71,338)	(44,588)	(31,713)
Acquisitions, net of cash acquired	(11,517)	(175,225)	(239,851)
Distributions from unconsolidated affiliates	9,223	863	45,879
Proceeds from sale of assets and insurance	27,438	16,974	37,089
Net cash used by investing activities	(46,194)	(201,976)	(188,596)
Financing activities:
Net proceeds from (payments of) short-term borrowings	(103,618)	(168,446)	97,626
Proceeds from long-term debt	247,566	150,000	5,880
Principal payments on long-term debt	(1,219)	(1,480)	(342)
Proceeds from issuance of common shares	4,618	37,914	11,116
Excess tax benefits - stock-based compensation	8,880	5,183	578
Payments to noncontrolling interest	(40,969)	(9,254)	(9,494)
Repurchase of common shares	(128,218)	(30,417)	(73,418)
Dividends paid	(31,198)	(44,144)	(32,138)
Net cash used by financing activities	(44,158)	(60,644)	(192)
Increase (decrease) in cash and cash equivalents	138,694	10,357	(15,139)
Cash and cash equivalents at beginning of year	51,385	41,028	56,167
Cash and cash equivalents at end of year	$ 190,079	$ 51,385	$ 41,028