Components of Changes in Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands		3 Months Ended
		Aug. 31, 2016	Aug. 31, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2016		$ 919,846
Income taxes		(463)	$ (608)
Balance as of August 31, 2016		981,080
Foreign Currency Translation
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2016		(18,728)
Other comprehensive income (loss) before reclassifications		(670)
Balance as of August 31, 2016		(19,398)
Pension Liability Adjustment
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2016		(17,061)
Balance as of August 31, 2016		(17,061)
Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2016		7,224
Other comprehensive income (loss) before reclassifications		733
Reclassification adjustments to income	[1]	355
Income taxes		(463)
Balance as of August 31, 2016		7,849
Accumulated Other Comprehensive Loss, Net of Tax
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2016		(28,565)
Balance as of August 31, 2016		(28,610)
Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance as of May 31, 2016		793,371
Other comprehensive income (loss) before reclassifications		63
Reclassification adjustments to income	[1]	355
Income taxes		(463)
Balance as of August 31, 2016		$ 855,962

[1] The statement of earnings classification of amounts reclassified to income for cash flow hedges is disclosed in "NOTE N - Derivative Instruments and Hedging Activities."