Goodwill and Intangible Assets - Schedule of Goodwill and Intangible Assets (Details) (USD $) In Thousands, unless otherwise specified	Aug. 31, 2014	May 31, 2014
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 1,324,374	$ 1,337,285
Other intangible assets	882,000	892,511
Less accumulated amortization	370,735	357,338
Other intangible assets, net	511,265	535,173
Customer-Related Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	708,157	714,704
Less accumulated amortization	328,293	317,629
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	5,575	6,140
Less accumulated amortization	4,239	4,147
Acquired Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	25,800	25,700
Less accumulated amortization	4,413	3,531
Contract-Based Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets	142,468	145,967
Less accumulated amortization	$ 33,790	$ 32,031