Consolidated Statements of Cash Flows - Entity [Domain] - USD ($) $ in Thousands	12 Months Ended
	May. 31, 2015	May. 31, 2014	May. 31, 2013
Operating activities:
Net earnings	$ 87,256	$ 160,152	$ 136,835
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	85,089	79,730	66,469
Impairment of goodwill and long-lived assets	100,129	58,246	6,488
Provision (benefit) for deferred income taxes	(39,960)	(25,916)	1,798
Bad debt expense	259	32	783
Equity in net income of unconsolidated affiliates, net of distributions	(12,299)	(15,333)	(10,948)
Net loss (gain) on sale of assets	3,277	(11,212)	1,121
Stock-based compensation	17,916	22,017	13,270
Excess tax benefits - stock-based compensation	(7,178)	(8,880)	(5,183)
Gain on previously held equity interest in TWB Company, L.L.C.		(11,000)
Changes in assets and liabilities, net of impact of acquisitions:
Receivables	32,011	(49,206)	18,801
Inventories	54,108	(38,010)	77,115
Prepaid expenses and other current assets	(15,295)	(2,921)	871
Other assets	1,617	(5,278)	4,636
Accounts payable and accrued expenses	(83,190)	69,682	(47,483)
Other liabilities	(9,365)	6,943	8,404
Net cash provided by operating activities	214,375	229,046	272,977
Investing activities:
Investment in property, plant and equipment	(96,255)	(71,338)	(44,588)
Investment in notes receivable	(7,300)
Acquisitions, net of cash acquired	(105,291)	(11,517)	(175,225)
Distributions from (investment in) unconsolidated affiliate(s)	(8,230)	9,223	863
Proceeds from sale of assets and insurance	14,007	27,438	16,974
Net cash used by investing activities	(203,069)	(46,194)	(201,976)
Financing activities:
Net proceeds from (payments of) short-term borrowings, net of issuance costs	79,047	(103,618)	(168,446)
Proceeds from long-term debt, net of issuance costs	30,572	247,566	150,000
Principal payments on long-term debt	(102,852)	(1,219)	(1,480)
Proceeds from issuance of common shares	2,910	4,618	37,914
Excess tax benefits - stock-based compensation	7,178	8,880	5,183
Payments to noncontrolling interests	(15,189)	(40,969)	(9,254)
Repurchase of common shares	(127,360)	(128,218)	(30,417)
Dividends paid	(46,434)	(31,198)	(44,144)
Net cash used by financing activities	(170,318)	(44,158)	(60,644)
Increase (decrease) in cash and cash equivalents	(159,012)	138,694	10,357
Cash and cash equivalents at beginning of year	190,079	51,385	41,028
Cash and cash equivalents at end of year	31,067	190,079	51,385
Noncontrolling Interest In Consolidated Entity
Financing activities:
Payments to noncontrolling interests	$ (13,379)	$ (40,969)	$ (9,254)