Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Operating activities:
Net earnings	$ 217,937	$ 157,628	$ 87,256
Adjustments to reconcile net earnings to net cash provided by operating activities:
Depreciation and amortization	86,793	84,699	85,089
Impairment of goodwill and long-lived assets		25,962	100,129
Provision for (benefit from) deferred income taxes	18,443	7,354	(39,960)
Bad debt expense	269	346	259
Equity in net income of unconsolidated affiliates, net of distributions	(8,023)	(29,473)	(12,299)
Net (gain) loss on assets	7,951	(12,996)	3,277
Stock-based compensation	14,349	15,836	17,916
Excess tax benefits - stock-based compensation			(7,178)
Gain on previously held equity interest in WSP		(6,877)
Changes in assets and liabilities, net of impact of acquisitions :
Receivables	(39,927)	66,117	32,011
Inventories	(34,599)	66,351	54,108
Prepaid expenses and other current assets	985	18,327	(15,295)
Other assets	1,905	(4,530)	1,617
Accounts payable and accrued expenses	67,492	20,180	(83,190)
Other liabilities	2,097	4,460	(9,365)
Net cash provided by operating activities	335,672	413,384	214,375
Investing activities:
Investment in property, plant and equipment	(68,386)	(97,036)	(96,255)
Investment in notes receivable			(7,300)
Acquisitions, net of cash acquired		(34,206)	(105,291)
Investments in unconsolidated affiliates		(5,595)	(8,230)
Proceeds from sale of assets and insurance	5,422	9,797	14,007
Net cash used by investing activities	(62,964)	(127,040)	(203,069)
Financing activities:
Net proceeds from (repayments of) short-term borrowings, net issuance costs	(2,528)	(85,843)	79,047
Proceeds from long-term debt, net of issuance costs		921	30,572
Principal payments on long-term debt	(874)	(862)	(102,852)
Proceeds from issuance of common shares, net of tax withholdings	(9,075)	8,707	2,910
Excess tax benefits - stock-based compensation			7,178
Payments to noncontrolling interests	(15,622)	(9,106)	(13,379)
Repurchase of common shares		(99,847)	(127,360)
Dividends paid	(50,716)	(47,193)	(46,434)
Net cash used by financing activities	(78,815)	(233,223)	(170,318)
Increase (decrease) in cash and cash equivalents	193,893	53,121	(159,012)
Cash and cash equivalents at beginning of year	84,188	31,067	190,079
Cash and cash equivalents at end of year	$ 278,081	$ 84,188	$ 31,067