Goodwill, Service Contracts and Other Assets - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	May 31, 2017	May 31, 2016	May 31, 2015
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 2,782,335	$ 1,276,076	$ 1,180,094
Continuing Operations
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	22,800	14,200	$ 12,100
Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract]
Estimated amortization expense, year one	60,000
Estimated amortization expense, year two	60,100
Estimated amortization expense, year three	59,500
Estimated amortization expense, year four	53,700
Estimated amortization expense, year five	53,100
Discontinued Operations, Held-for-sale
Finite-Lived Intangible Assets [Line Items]
Goodwill	$ 15,500	$ 15,500