Debt 3 (Details)	12 Months Ended
Mar. 31, 2012 Revolving Credit Facility due August 2016 [Member]	Mar. 31, 2011 Revolving Credit Facility due August 2012 [Member]
Interest rates applicable to revolving credit facility
Applicable margin on base borrowing	0.25%
Weighted average interest rate on outstanding borrowings		0.65%
Applicable margin on Eurocurrency borrowing	1.10%	0.35%
Utilization Fee	0.00%	0.10%
Facility commitment fee	0.15%	0.10%

Reflects the calculation as of the balance sheet date of the average interest rate weighted by the amount of long-term debt outstanding by type or by instrument at that time.

No definition available.

Name:	us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant