Stock-Based Compensation (Details 7) (Restricted stock and restricted unit, USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Restricted stock and restricted unit
Stock based compensation disclosure
Unvested shares, at the beginning of the period (in shares)	2,873	2,637	1,605
Granted (in shares)	2,185	1,370	1,867
Vested (in shares)	(1,177)	(1,075)	(617)
Canceled/ forfeited (in shares)	(143)	(59)	(218)
Unvested shares, at the end of the period (in shares)	3,738	2,873	2,637
Unvested shares, at the beginning of the period (in dollars per share)	$ 33.83	$ 33.01	$ 34.80
Granted (in dollars per share)	$ 24.04	$ 33.48	$ 33.02
Vested (in dollars per share)	$ 31.22	$ 31.49	$ 38.62
Canceled/ forfeited (in dollars per share)	$ 58.30	$ 32.68	$ 30.42
Unvested shares, at the end of the period (in dollars per share)	$ 27.99	$ 33.83	$ 33.01
Compensation expense relating to restricted stock and restricted stock units	$ 46,351	$ 32,826	$ 35,770
Restricted Stock Expense, Tax Benefit	17,697	12,705	13,854
Unamortized Compensation Cost on Unvested Restricted Stock Awards	$ 66,854
Expected term over which unamortized compensation is to be recognized	1 year 220 days