Condensed Consolidating Financial Information - Condensed Consolidating Statement of Operations (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	May 31, 2013	May 31, 2012	May 31, 2011
Schedule of Condensed Consolidating Statement of Operations [Line Items]
NET SALES	$ 697,081	$ 594,105	$ 571,906
Cost of products sold	629,803	560,573	556,925
GROSS PROFIT	67,278	33,532	14,981
Selling, general and administrative	67,657	68,363	72,049
Restructuring charges	0	3,153	0
Interest	32,807	34,835	47,583
Loss on debt retirements	0	0	29,619
Other income	(8,926)	(73,106)	(20,921)
Intercompany other income	0	0	0
TOTAL EXPENSES	91,538	33,245	128,330
Income (loss) from continuing operations before the following items	(24,260)	287	(113,349)
Income taxes (benefit)	(13,766)	(1,641)	(43,877)
Net income (loss) before equity in earnings (loss) of subsidiaries	(10,494)	1,928	(69,472)
Equity in earnings of subsidiaries	0	0	0
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	(10,494)	1,928	(69,472)
Net income from discontinued operations	35,044	5,548	4,559
Net income (loss)	24,550	7,476	(64,913)
Net comprehensive income (loss)	30,694	(4,260)	(63,525)
Parent Company
Schedule of Condensed Consolidating Statement of Operations [Line Items]
NET SALES	0	0	0
Cost of products sold	0	0	0
GROSS PROFIT	0	0	0
Selling, general and administrative	9,133	9,349	8,810
Restructuring charges		0
Interest	68,885	68,291	66,101
Loss on debt retirements	0	0	29,619
Other income	(70)	(56)	(200)
Intercompany other income	(3,501)	(3,500)	(3,500)
TOTAL EXPENSES	74,447	74,084	100,830
Income (loss) from continuing operations before the following items	(74,447)	(74,084)	(100,830)
Income taxes (benefit)	(30,805)	(27,345)	(37,475)
Net income (loss) before equity in earnings (loss) of subsidiaries	(43,642)	(46,739)	(63,355)
Equity in earnings of subsidiaries	68,193	54,215	(1,558)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	24,551	7,476	(64,913)
Net income from discontinued operations	0	0	0
Net income (loss)	24,551	7,476	(64,913)
Net comprehensive income (loss)	24,551	7,476	(64,913)
Guarantor Subsidiaries
Schedule of Condensed Consolidating Statement of Operations [Line Items]
NET SALES	697,081	594,105	571,906
Cost of products sold	629,803	560,573	556,925
GROSS PROFIT	67,278	33,532	14,981
Selling, general and administrative	58,524	59,014	63,239
Restructuring charges		3,153
Interest	0	0	0
Loss on debt retirements	0	0	0
Other income	(8,856)	(73,050)	(20,721)
Intercompany other income	(32,577)	(29,956)	(15,018)
TOTAL EXPENSES	17,091	(40,839)	27,500
Income (loss) from continuing operations before the following items	50,187	74,371	(12,519)
Income taxes (benefit)	17,039	25,704	(6,402)
Net income (loss) before equity in earnings (loss) of subsidiaries	33,148	48,667	(6,117)
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	33,148	48,667	(6,117)
Net income from discontinued operations	35,044	5,548	4,559
Net income (loss)	68,192	54,215	(1,558)
Net comprehensive income (loss)	74,336	42,479	(170)
Consolidating Adjustments
Schedule of Condensed Consolidating Statement of Operations [Line Items]
NET SALES	0	0	0
Cost of products sold	0	0	0
GROSS PROFIT	0	0	0
Selling, general and administrative	0	0	0
Restructuring charges		0
Interest	(36,078)	(33,456)	(18,518)
Loss on debt retirements	0	0	0
Other income	0	0	0
Intercompany other income	36,078	33,456	18,518
TOTAL EXPENSES	0	0	0
Income (loss) from continuing operations before the following items	0	0	0
Income taxes (benefit)	0	0	0
Net income (loss) before equity in earnings (loss) of subsidiaries	0	0	0
Equity in earnings of subsidiaries	(68,193)	(54,215)	1,558
NET INCOME (LOSS) FROM CONTINUING OPERATIONS	(68,193)	(54,215)	1,558
Net income from discontinued operations	0	0	0
Net income (loss)	(68,193)	(54,215)	1,558
Net comprehensive income (loss)	$ (68,193)	$ (54,215)	$ 1,558