Significant Accounting Policies Goodwill and Other Intangibles (Details)	12 Months Ended
	Mar. 31, 2013
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	20 years
Internally Developed Software [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	5 years
Minimum [Member] | Supply Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	3 years
Minimum [Member] | Production Contract [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	5 years
Maximum [Member] | Supply Contracts [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	5 years
Maximum [Member] | Production Contract [Member]
Finite-Lived Intangible Assets [Line Items]
Useful life (in years)	10 years