Changes in Equity - Summary of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Nov. 30, 2018	Nov. 30, 2017	Nov. 30, 2018	Nov. 30, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		$ 1,037,374	$ 1,082,727	$ 1,036,375	$ 1,073,929
Income taxes		(1,404)	(1,285)	(1,864)	(173)
Ending Balance		986,255	1,042,783	986,255	1,042,783
Accumulated Foreign Currency Adjustment Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance				(4,987)
Other comprehensive loss before reclassifications				(10,261)
Ending Balance		(15,248)		(15,248)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance				(16,071)
Income taxes				(97)
Ending Balance		(16,168)		(16,168)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance				6,478
Other comprehensive loss before reclassifications				(4,530)
Reclassification adjustments to income	[1]			(4,063)
Income taxes				1,961
Ending Balance		(154)		(154)
AOCI Attributable to Parent
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning Balance		(20,325)	(10,461)	(14,580)	(27,775)
Other comprehensive loss before reclassifications				(14,791)
Reclassification adjustments to income	[1]			(4,063)
Income taxes				1,864
Ending Balance		$ (31,570)	$ (11,080)	$ (31,570)	$ (11,080)

[1] The statement of earnings classification of amounts reclassified to income for cash flow hedges is disclosed in “NOTE O – Derivative Instruments and Hedging Activities.”