Note 18. Segment and Geographic Information (Detail) - Sales by Geographic Segment (USD $) In Thousands, unless otherwise specified	3 Months Ended								9 Months Ended		12 Months Ended
	May 31, 2012	Feb. 29, 2012	Nov. 30, 2011	Aug. 19, 2011	May 31, 2011	Feb. 28, 2011	Nov. 30, 2010	Aug. 31, 2010	May 31, 2012	May 31, 2012	Aug. 31, 2012	May 31, 2011	May 31, 2010
Sales:
Net Sales	$ 86,019	$ 81,370	$ 83,035	$ 74,910	$ 84,555	$ 83,349	$ 81,546	$ 83,641		$ 261,814	$ 11,390	$ 333,091	$ 329,073
Income (loss) from operations	11,553	9,113	(24,713)	(6,508)	27,971	33,867	31,957	32,202		(4,599)	(552)	125,997	125,342
Depreciation				3,400						15,500		13,900	12,300
Income tax expense (benefit)				2,681						(31,546)		41,303	42,629
Interest income				142						7		706	454
Interest expense										77,048		70	33
Certain litigation expenses									22,000	22,000
Property & equipment, net	64,662				58,216				64,662	64,662		58,216
Goodwill	966,338				93,767				966,338	966,338		93,767
Intangible assets	735,522				54,133				735,522	735,522		54,133
Total assets at period end	1,949,153				633,127				1,949,153	1,949,153		633,127
Unaffiliated Customers [Member] | United States [Member]
Sales:
Net Sales				52,364						178,875		232,965	236,255
Unaffiliated Customers [Member] | Europe [Member]
Sales:
Net Sales				15,100						55,495		68,569	65,096
Unaffiliated Customers [Member] | Other Geographic Area [Member]
Sales:
Net Sales				7,446						27,444		31,557	27,722
Unaffiliated Customers [Member] | Consolidated [Member]
Sales:
Net Sales				74,910						261,814		333,091	329,073
Affiliates [Member] | United States [Member]
Sales:
Net Sales				3,679						20,590		15,950	17,291
Affiliates [Member] | Europe [Member]
Sales:
Net Sales				3,992						14,264		16,300	14,508
Affiliates [Member] | Other Geographic Area [Member]
Sales:
Net Sales				110						324		323	280
Affiliates [Member] | Geographical Intersegment, Eliminations [Member]
Sales:
Net Sales				(7,781)						(35,178)		(32,573)	(32,079)
Total [Member] | United States [Member]
Sales:
Net Sales				56,043						199,465		248,915	253,546
Total [Member] | Europe [Member]
Sales:
Net Sales				19,092						69,759		84,869	79,604
Total [Member] | Other Geographic Area [Member]
Sales:
Net Sales				7,556						27,768		31,880	28,002
Total [Member] | Geographical Intersegment, Eliminations [Member]
Sales:
Net Sales				(7,781)						(35,178)		(32,573)	(32,079)
Total [Member] | Consolidated [Member]
Sales:
Net Sales				74,910						261,814		333,091	329,073
United States [Member]
Sales:
Income (loss) from operations				(10,298)						(6,726)		100,774	105,447
Depreciation				2,106						10,357		9,093	7,879
Amortization				874						37,334		4,084	4,034
Income tax expense (benefit)				(89)						(32,414)		33,322	36,271
Interest income				47								279	221
Interest expense										77,046		57	18
Certain litigation expenses										22,000
Capital expenditures				545						4,422		6,717	5,753
Property & equipment, net	45,509			40,684	39,957				45,509	45,509		39,957	36,334
Goodwill	910,171			70,946	70,946				910,171	910,171		70,946	73,881
Intangible assets	692,625			45,871	46,745				692,625	692,625		46,745	50,828
Total assets at period end	2,013,165			732,603	677,861				2,013,165	2,013,165		677,861	594,005
Europe [Member]
Sales:
Income (loss) from operations				1,619						2,708		13,397	9,698
Depreciation				1,123						4,532		4,258	3,956
Amortization				36						1,304		160	162
Income tax expense (benefit)				637						1,067		4,171	3,214
Interest income				40						6		234	177
Interest expense										2		14	15
Capital expenditures				1,386						790		407	361
Property & equipment, net	14,393			13,755	14,318				14,393	14,393		14,318	10,945
Goodwill	32,977			7,239	7,214				32,977	32,977		7,214	6,235
Intangible assets	29,066			1,139	1,169				29,066	29,066		1,169	1,181
Total assets at period end	134,905			92,440	92,866				134,905	134,905		92,866	69,151
Other Geographic Area [Member]
Sales:
Income (loss) from operations				2,171						243		11,819	9,782
Depreciation				161						632		529	456
Amortization				21						586		89	82
Income tax expense (benefit)				2,145						89		3,802	2,879
Interest income				55						1		193	56
Interest expense												(1)
Capital expenditures				334						752		1,937	190
Property & equipment, net	4,760			4,147	3,941				4,760	4,760		3,941	1,890
Goodwill	23,190			15,880	15,607				23,190	23,190		15,607	14,220
Intangible assets	13,831			6,592	6,219				13,831	13,831		6,219	5,619
Total assets at period end	56,632			39,199	64,992				56,632	56,632		64,992	51,337
Geographical Intersegment, Eliminations [Member]
Sales:
Income (loss) from operations										(824)		7	415
Income tax expense (benefit)				(12)						(288)		8	265
Total assets at period end	(255,549)			(211,847)	(202,592)				(255,549)	(255,549)		(202,592)	(194,659)
Consolidated [Member]
Sales:
Income (loss) from operations				(6,508)						(4,599)		125,997	125,342
Depreciation				3,390						15,521		13,880	12,291
Amortization				931						39,224		4,333	4,278
Income tax expense (benefit)				2,681						(31,546)		41,303	42,629
Interest income				142						7		706	454
Interest expense										77,048		70	33
Certain litigation expenses										22,000
Capital expenditures				2,265						5,964		9,061	6,304
Property & equipment, net	64,662			58,586	58,216				64,662	64,662		58,216	49,169
Goodwill	966,338			94,065	93,767				966,338	966,338		93,767	94,336
Intangible assets	735,522			53,602	54,133				735,522	735,522		54,133	57,628
Total assets at period end	$ 1,949,153			$ 652,395	$ 633,127				$ 1,949,153	$ 1,949,153		$ 633,127	$ 519,834