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Consolidated Statement of Equity (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Non-controlling Interest
Beginning Balance at May. 31, 2014	$ 306,300	$ 5,877	$ 118,070	$ 371	$ 182,043	$ (61)
Beginning Balance (in shares) at May. 31, 2014		36,732
Issuance of shares of common stock under equity compensation plans, and share based compensation (in shares)		290
Issuance of shares of common stock under equity compensation plans, and share based compensation	8,051	47	8,004
Issuance of shares under employee stock purchase plan (in shares)		20
Issuance of shares under employee stock purchase plan	724	3	721
Comprehensive income:
Net income for the nine months ended February 28, 2015	24,143us-gaap_ProfitLoss				24,142	1
Other comprehensive loss	(2,505)			(2,505)
Ending Balance at Feb. 28, 2015	$ 336,713	$ 5,927	$ 126,795	$ (2,134)	$ 206,185	$ (60)
Ending Balance (in shares) at Feb. 28, 2015		37,042