Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Stock based compensation disclosure
Shares available for issuance under equity incentive plan (in shares)	6,306,000
Increase In Available Shares	6,500
Share-based Compensation Arrangement by Share-based Payment Award Granted Price as Percentage of Fair Market Value Minimum	100.00%
Share-based Compensation Option Exercisable Period from Date of Grant Low End of Range	4
Share-based Compensation Option Exercisable Period from Date of Grant High End of Range	5
Share-based Compensation Option Expiration Period from Date of Grant Low End of Range	8
Share-based Compensation Option Expiration Period from Date of Grant High End of Range	10
Compensation expense relating to stock options	$ 4,181	$ 4,633
Stock Option Transactions
Options outstanding, beginning of period (in shares)	5,419,000	6,054,000
Granted (in shares)	810,000	689,000
Exercised (in shares)	(6,000)	(142,000)
Canceled/forfeited (in shares)	(54,000)	(61,000)
Options outstanding, end of period (in shares)	6,169,000	6,540,000
Options outstanding, beginning of period (in dollars per share)	$ 59.82	$ 57.75
Granted (in dollars per share)	$ 33.99	$ 33.25
Exercised (in dollars per share)	$ 29.73	$ 26.12
Canceled/forfeited (in dollars per share)	$ 48.18	$ 55.58
Options outstanding, end of period (in dollars per share)	$ 56.56	$ 55.88
Options exercisable (in shares)	2,963,000
Weighted-average exercise price per share of exercisable options (in dollars per share)	$ 75.53
Weighted-average remaining contractual life of exercisable options (in years)	3.2
Unvested options, shares	3,206,000
Unamortized compensation cost related to unvested options	$ 34,075
Weighted-average period over which compensation cost related to unvested options is expected to be recognized (in years)	2.0
Summary of unvested stock options under equity incentive plans
Weighted Average Grant Date Fair Value, granted (in dollar per share)	$ 13.13	$ 14.44