Calculation of Basic and Diluted EPS (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Nov. 30, 2013		Nov. 30, 2012		Nov. 30, 2013		Nov. 30, 2012
Earnings
Net loss from continuing operations	$ (17,640)		$ (10,189)		$ (17,210)		$ (17,583)
Net income (loss) from discontinued operations	0		(933)		0		3,805
Loss allocated to common shareholders	$ (17,640)		$ (11,122)		$ (17,210)		$ (13,778)
Shares
Weighted-average shares outstanding (in shares)	28,615		28,043		28,601		28,028
Contingently issuable shares (in shares)	6		3		6		3
Unvested restricted shares (in shares)	(7)		(16)		(11)		(17)
Basic weighted-average shares (in shares)	28,614		28,030		28,596		28,014
Diluted weighted-average shares (1) (in shares)	28,614	[1]	28,030	[1]	28,596	[1]	28,014	[1]
NET LOSS PER SHARE FROM CONTINUING OPERATIONS:
Basic (in USD per share)	$ (0.62)		$ (0.36)		$ (0.60)		$ (0.63)
Diluted (in USD per share)	$ (0.62)		$ (0.36)		$ (0.60)		$ (0.63)
NET INCOME (LOSS) PER SHARE FROM DISCONTINUED OPERATIONS:
Basic (in USD per share)	$ 0.00		$ (0.04)		$ 0.00		$ 0.14
Diluted (in USD per share)	$ 0.00		$ (0.04)		$ 0.00		$ 0.14
NET LOSS PER SHARE:
Basic (in USD per share)	$ (0.62)		$ (0.40)		$ (0.60)		$ (0.49)
Diluted (in USD per share)	$ (0.62)		$ (0.40)		$ (0.60)		$ (0.49)
Shares excluded due to antidilutive effect of stock options, restricted shares and awards (in shares)	542		826		550		978

[1] Shares excluded due to antidilutive effect of stock options, restricted shares and awards