Other Expense (Income), Net (Detail) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Feb. 28, 2019	Feb. 28, 2018	Feb. 28, 2019	Feb. 28, 2018
Other Income And Expenses [Abstract]
Royalty expense, net		$ 88	$ 148	$ 154	$ 238
(Income) related to unconsolidated equity affiliates		(133)	(313)	(299)	(830)
Pension non-service costs		372		1,146
Loss on extinguishment of debt	[1]			3,051
Other expense (income), net		$ 327	$ (165)	$ 4,052	$ (592)

[1] In connection with the redemption of all of our outstanding 2.25% convertible senior notes in November 2018, we recognized a loss of $3.1 million, due to the fair value measurement of the instrument on the date of conversion.