Goodwill and Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Nov. 30, 2011	May 31, 2011
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 741,081	$ 779,637
Other intangible assets	514,115	538,566
Accumulated amortization	214,435	197,066
Other intangible assets, net	299,680	341,500
Customer-related [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	437,687	457,226
Accumulated amortization	196,080	181,372
Trademarks, finite life [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	8,135	8,659
Accumulated amortization	4,490	4,138
Contract-based [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	68,293	72,681
Accumulated amortization	$ 13,865	$ 11,556