Fair Value Measurements (Tables)

9 Months Ended

Feb. 29, 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 February 29, 2016
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	265,149	$	49,967	$	—	$	315,116
Marketable securities:
Canadian treasury securities	—		71,703		—		71,703
Total assets at fair value	$	265,149	$	121,670	$	—	$	386,819
Long term accrued liabilities:
Interest rate lock agreement	$	—	$	22,438	$	—	$	22,438
Total liabilities at fair value	$	—	$	22,438	$	—	$	22,438

	As of May 31, 2015
(In thousands)	Level 1		Level 2		Level 3		Fair Value
Cash and cash equivalents	$	417,073	$	—	$	—	$	417,073
Marketable securities:
Canadian treasury securities	—		16,081		—		16,081
Total assets at fair value	$	417,073	$	16,081	$	—	$	433,154