Condensed Consolidating Statement of Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 28, 2013	Feb. 29, 2012	Feb. 28, 2013	Feb. 29, 2012
Schedule of Condensed Consolidating Statement of Operations [Line Items]
NET SALES	$ 141,359	$ 121,894	$ 483,575	$ 435,696
Cost of products sold	129,035	123,774	444,297	425,464
GROSS PROFIT	12,324	(1,880)	39,278	10,232
Selling, general and administrative	17,056	17,265	51,679	46,774
Restructuring charges	0	0	0	3,153
Interest	7,227	8,512	22,462	26,810
Other income	(2,091)	(1,332)	(6,614)	(8,725)
Intercompany other income	0	0	0	0
TOTAL EXPENSES	22,192	24,445	67,527	68,012
Income (loss) from continuing operations before the following items	(9,868)	(26,325)	(28,249)	(57,780)
Income taxes (benefit)	(1,355)	(1,148)	(2,151)	(2,601)
Net income (loss) before equity in earnings (loss) of subsidiaries	(8,513)	(25,177)	(26,098)	(55,179)
Equity in earnings of subsidiaries	0	0	0	0
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
Net income (loss)	(5,814)	(24,280)	(19,594)	(52,737)
Comprehensive loss	(5,718)	(24,040)	(19,033)	(52,018)
Parent Company
Schedule of Condensed Consolidating Statement of Operations [Line Items]
NET SALES	0	0	0	0
Cost of products sold	0	0	0	0
GROSS PROFIT	0	0	0	0
Selling, general and administrative	2,762	2,330	7,446	3,583
Restructuring charges		0
Interest	17,309	17,016	51,545	51,281
Other income	(13)	(16)	(62)	(43)
Intercompany other income	(863)	(863)	(2,618)	(2,618)
TOTAL EXPENSES	19,195	18,467	56,311	52,203
Income (loss) from continuing operations before the following items	(19,195)	(18,467)	(56,311)	(52,203)
Income taxes (benefit)	517	(9,139)	441	(12,673)
Net income (loss) before equity in earnings (loss) of subsidiaries	(19,712)	(9,328)	(56,752)	(39,530)
Equity in earnings of subsidiaries	13,898	(14,952)	37,159	(13,207)
NET LOSS FROM CONTINUING OPERATIONS	(5,814)	(24,280)	(19,593)	(52,737)
Net income (loss) from discontinued operations	0	0	0	0
Net income (loss)	(5,814)	(24,280)	(19,593)	(52,737)
Comprehensive loss	(5,814)	(24,280)	(19,593)	(52,737)
Guarantor Subsidiaries
Schedule of Condensed Consolidating Statement of Operations [Line Items]
NET SALES	141,359	121,894	483,575	435,696
Cost of products sold	129,035	123,774	444,297	425,464
GROSS PROFIT	12,324	(1,880)	39,278	10,232
Selling, general and administrative	14,294	14,935	44,233	43,191
Restructuring charges		0		3,153
Interest	0	0	0	0
Other income	(2,078)	(1,316)	(6,552)	(8,682)
Intercompany other income	(9,219)	(7,641)	(26,465)	(21,853)
TOTAL EXPENSES	2,997	5,978	11,216	15,809
Income (loss) from continuing operations before the following items	9,327	(7,858)	28,062	(5,577)
Income taxes (benefit)	(1,872)	7,991	(2,592)	10,072
Net income (loss) before equity in earnings (loss) of subsidiaries	11,199	(15,849)	30,654	(15,649)
NET LOSS FROM CONTINUING OPERATIONS	11,199	(15,849)	30,654	(15,649)
Net income (loss) from discontinued operations	2,699	897	6,504	2,442
Net income (loss)	13,898	(14,952)	37,158	(13,207)
Comprehensive loss	13,994	(14,712)	37,719	(12,488)
Consolidation, Eliminations
Schedule of Condensed Consolidating Statement of Operations [Line Items]
NET SALES	0	0	0	0
Cost of products sold	0	0	0	0
GROSS PROFIT	0	0	0	0
Selling, general and administrative	0	0	0	0
Restructuring charges		0
Interest	(10,082)	(8,504)	(29,083)	(24,471)
Other income	0	0	0	0
Intercompany other income	10,082	8,504	29,083	24,471
TOTAL EXPENSES	0	0	0	0
Income (loss) from continuing operations before the following items	0	0	0	0
Income taxes (benefit)	0	0	0	0
Net income (loss) before equity in earnings (loss) of subsidiaries	0	0	0	0
Equity in earnings of subsidiaries	(13,898)	14,952	(37,159)	13,207
NET LOSS FROM CONTINUING OPERATIONS	(13,898)	14,952	(37,159)	13,207
Net income (loss) from discontinued operations	0	0	0	0
Net income (loss)	(13,898)	14,952	(37,159)	13,207
Comprehensive loss	$ (13,898)	$ 14,952	$ (37,159)	$ 13,207