Related Parties - Additional Information (Detail) (USD $)	3 Months Ended				1 Months Ended	3 Months Ended
	Aug. 31, 2012 Employees	Aug. 31, 2011	May 31, 2011	Jun. 13, 2007	Aug. 08, 2012 6.500% senior notes due 2020 [Member]	Aug. 31, 2012 6.500% senior notes due 2020 [Member]	Aug. 31, 2012 Minimum [Member]	Aug. 31, 2012 Maximum [Member]	Jul. 11, 2007 Senior Secured Term Loan Facility [Member]
Related Party Transaction [Line Items]
Offer Price				$ 46.00
Amount of credit agreement									$ 6,165,000,000
Borrowings to finance portion of the Offer and pay related fees and expenses	4,181,000,000
Credit agreement maturity date	Jul-11-2007
Percentage of outstanding Shares tendered to Purchaser	82.00%
Percentage of hareholders voted to approve the proposed merger	91.00%
Date of acquisition	Sep. 25, 2007
Percentage of transaction fee on total enterprise value	1.00%
Percentage of annual monitoring fee on Company's annual Adjusted EBITDA	1.00%
Total amount of Sponsor fees	2,600,000	2,000,000
Minimum percentage of membership interests that the sponsors should hold	70.00%
Consulting fee	250,000
Out-of-pocket fees and expenses relating to an off-site office and administrative support	100,000						100,000	150,000
Amount paid under under consulting agreement	100,000	100,000
Fee per participating employee per month	2
Number of employees enrolled in its health benefit plans	3,200
Percentage of purchase requirements	80.00%
Total amount of fees paid	100,000	100,000
Aggregate principal amount					1,000,000,000	1,000,000,000
Stated percentage of senior notes					6.50%	6.50%
Senior Note due					2020	2020
Fees received	100,000
Underwriting discount received	2,300,000
Amount paid to consulting company	500,000	600,000
Repurchase of common shares			$ 300,000