Calculation of Basic and Diluted EPS (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Feb. 28, 2013		Feb. 29, 2012		Feb. 28, 2013		Feb. 29, 2012
Earnings
Net loss from continuing operations	$ (8,513)		$ (25,177)		$ (26,098)		$ (55,179)
Net income (loss) from discontinued operations	2,699		897		6,504		2,442
Unvested restricted share participation	5		12		16		26
Loss allocated to common shareholders	$ (5,809)		$ (24,268)		$ (19,578)		$ (52,711)
Shares
Weighted-average shares outstanding (in shares)	28,200		27,936		28,086		27,906
Contingently issuable shares (in shares)	4		3		3		2
Unvested restricted shares (in shares)	(14)		(13)		(16)		(14)
Basic weighted-average shares (in shares)	28,190		27,926		28,073		27,894
Stock option, restricted share and award dilution (in shares)	0		0		0		0
Diluted weighted-average shares (1) (in shares)	28,190	[1]	27,926	[1]	28,073	[1]	27,894	[1]
NET LOSS PER SHARE FROM CONTINUING OPERATIONS:
Basic (in USD per share)	$ (0.30)		$ (0.90)		$ (0.93)		$ (1.98)
Diluted (in USD per share)	$ (0.30)		$ (0.90)		$ (0.93)		$ (1.98)
NET INCOME FROM DISCONTINUED OPERATIONS:
Basic (in USD per share)	$ 0.09		$ 0.03		$ 0.23		$ 0.09
Diluted (in USD per share)	$ 0.09		$ 0.03		$ 0.23		$ 0.09
NET LOSS PER SHARE:
Basic (in USD per share)	$ (0.21)		$ (0.87)		$ (0.70)		$ (1.89)
Diluted (in USD per share)	$ (0.21)		$ (0.87)		$ (0.70)		$ (1.89)
Shares excluded due to antidilutive effect of stock options, restricted shares and awards (in shares)	583		1,420		409		1,380

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