Fair Value Disclosures (Tables)

12 Months Ended

May 31, 2017

Fair Value Disclosures [Abstract]

Summary of Financial Instruments Measured at Fair Value on a Recurring Basis

These financial instruments measured at fair value on a recurring basis are summarized below:

	As of May 31, 2017
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	169,266	$	—	$	—	$	169,266
Marketable securities:
Canadian treasury securities	—		22,219		—		22,219
Total assets at fair value	$	169,266	$	22,219	$	—	$	191,485

	As of May 31, 2016
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	139,357	$	—	$	—	$	139,357
Marketable securities:
Canadian treasury securities	—		70,405		—		70,405
Total assets at fair value	$	139,357	$	70,405	$	—	$	209,762
Long-term accrued liabilities:
Interest rate lock agreement	$	—	$	19,628	$	—	$	19,628
Total liabilities at fair value	$	—	$	19,628	$	—	$	19,628