Fair Value Measurements (Tables)

3 Months Ended

Aug. 31, 2016

Fair Value Disclosures [Abstract]

Schedule of Fair Value of Financial Instruments Measured on a Recurring Basis

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

	As of August 31, 2016
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	99,209	$	—	$	—	$	99,209
Marketable securities:
Canadian treasury securities	—		64,558		—		64,558
Total assets at fair value	$	99,209	$	64,558	$	—	$	163,767
Long-term accrued liabilities:
Interest rate lock agreement	$	—	$	38,827	$	—	$	38,827
Total liabilities at fair value	$	—	$	38,827	$	—	$	38,827

	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