Investments in Unconsolidated Affiliates - Schedule of Combined Financial Information for Unconsolidated Affiliates (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018	May 31, 2018
Equity Method Investments And Joint Ventures [Abstract]
Cash	$ 41,087		$ 41,087		$ 52,812
Other current assets	595,417		595,417		590,578
Current assets for discontinued operations	35,609		35,609		37,640
Noncurrent assets	363,992		363,992		358,927
Total assets	1,036,105		1,036,105		1,039,957
Current liabilities	234,230		234,230		166,493
Current liabilities for discontinued operations	8,744		8,744		7,142
Short-term borrowings	21,983		21,983		26,599
Current maturities of long-term debt	23,216		23,216		23,243
Long-term debt	322,306		322,306		259,588
Other noncurrent liabilities	18,734		18,734		17,536
Equity	406,892		406,892		539,356
Total liabilities and equity	1,036,105		1,036,105		$ 1,039,957
Net sales	454,579	$ 403,426	1,433,840	$ 1,258,667
Gross margin	77,706	72,828	257,033	230,185
Operating income	47,392	41,546	164,360	133,313
Depreciation and amortization	6,310	5,406	19,368	18,534
Interest expense	3,529	2,564	9,836	7,517
Income tax expense (benefit)	1,877	(1,095)	9,970	2,069
Net earnings from continuing operations	40,196	36,058	141,613	118,995
Net earnings from discontinued operations	1,001	1,805	4,713	1,532
Net earnings	$ 41,197	$ 37,863	$ 146,326	$ 120,527