Significant Accounting Policies Estimated Useful Lives (Details)	12 Months Ended
	May 31, 2012 Years
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum (in years)	30
Property, Plant and Equipment, Useful Life, Maximum (in years)	40
Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum (in years)	5
Property, Plant and Equipment, Useful Life, Maximum (in years)	20
Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum (in years)	3
Property, Plant and Equipment, Useful Life, Maximum (in years)	10
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life, Minimum (in years)	2
Property, Plant and Equipment, Useful Life, Maximum (in years)	15