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, 2014		Feb. 28, 2013		Feb. 28, 2014		Feb. 28, 2013
Earnings
Net loss from continuing operations	$ (21,769)		$ (8,513)		$ (38,979)		$ (26,098)
Net income from discontinued operations	0		2,699		0		6,504
Loss allocated to common shareholders	$ (21,769)		$ (5,814)		$ (38,979)		$ (19,594)
Shares
Weighted-average shares outstanding (in shares)	28,691		28,200		28,631		28,086
Contingently issuable shares (in shares)	5		4		5		3
Unvested restricted shares (in shares)	0		(14)		(7)		(16)
Basic weighted-average shares (in shares)	28,696		28,190		28,629		28,073
Diluted weighted-average shares (1) (in shares)	28,696	[1]	28,190	[1]	28,629	[1]	28,073	[1]
NET LOSS PER SHARE FROM CONTINUING OPERATIONS:
Basic (in USD per share)	$ (0.76)		$ (0.30)		$ (1.36)		$ (0.93)
Diluted (in USD per share)	$ (0.76)		$ (0.30)		$ (1.36)		$ (0.93)
NET INCOME PER SHARE FROM DISCONTINUED OPERATIONS:
Basic (in USD per share)	$ 0.00		$ 0.09		$ 0.00		$ 0.23
Diluted (in USD per share)	$ 0.00		$ 0.09		$ 0.00		$ 0.23
NET LOSS PER SHARE:
Basic (in USD per share)	$ (0.76)		$ (0.21)		$ (1.36)		$ (0.70)
Diluted (in USD per share)	$ (0.76)		$ (0.21)		$ (1.36)		$ (0.70)
Shares excluded due to antidilutive effect of stock options, restricted shares and awards (in shares)	634		583		595		409

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