Significant Accounting Policies (Estimated Useful Lives) (Details)	12 Months Ended
	May 31, 2013
Minimum [Member] | Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful lives (years)	30 years
Minimum [Member] | Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful lives (years)	5 years
Minimum [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful lives (years)	3 years
Minimum [Member] | Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful lives (years)	2 years
Maximum [Member] | Buildings [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful lives (years)	40 years
Maximum [Member] | Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful lives (years)	20 years
Maximum [Member] | Equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful lives (years)	10 years
Maximum [Member] | Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, useful lives (years)	15 years