Long-Term Debt Convertible Note Hedge and Warrant Transactions (Details)	12 Months Ended
	Mar. 31, 2015 counterparty	Mar. 31, 2014 $ / shares shares	Jul. 02, 2009 $ / shares
Debt Disclosure [Abstract]
Number of counterparties | counterparty	3
Class of warrant or right, exercise price of warrants or rights (in dollars per share) | $ / shares		$ 7.3325	$ 5.0280
Class of warrant or right, number of securities called by warrants or rights (in shares) | shares		45,743,836