Debt facility	12 Months Ended
Mar. 31, 2013
Debt facility [Abstract]
Debt facility	10. Debt facility: On December 4, 2012, the Company established a $750 million revolving credit facility for the purpose of providing financial liquidity for financing strategic business development and general corporate purposes. This revolving credit facility expires on December 4, 2017 and replaces the $500 million credit agreement that expired on December 7, 2012. The facility can be increased to $1.0 billion based upon agreement with the participating lenders. As of May 22, 2013, the Company has not drawn any funds from the available credit. The utilization of the revolving credit facility is subject to the adherence to certain financial covenants such as leverage and interest coverage ratios.

Debt facility

12 Months Ended

Mar. 31, 2013

10. Debt facility:

On December 4, 2012, the Company established a $750 million revolving credit facility for the purpose of providing financial liquidity for financing strategic business development and general corporate purposes. This revolving credit facility expires on December 4, 2017 and replaces the $500 million credit agreement that expired on December 7, 2012. The facility can be increased to $1.0 billion based upon agreement with the participating lenders. As of May 22, 2013, the Company has not drawn any funds from the available credit. The utilization of the revolving credit facility is subject to the adherence to certain financial covenants such as leverage and interest coverage ratios.