Stock-Based Compensation Plans (Details 3) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Jun. 30, 2012	Mar. 31, 2012
Summary of restricted stock unit activity and related information
Number of Shares, Beginning balance	5,239	4,215
Number of Shares, Granted	56	2,977
Number of Shares, Vested	(81)	(1,543)
Number of Shares, Cancelled	(78)	(410)
Number of Shares, Ending balance	5,136	5,239
Weighted-Average Grant-Date Fair Value, Beginning balance	$ 29.01	$ 23.19
Weighted-Average Grant-Date Fair Value, Granted	$ 31.35	$ 33.69
Weighted-Average Grant-Date Fair Value, Vested	$ 27.47	$ 23.11
Weighted-Average Grant-Date Fair Value, Cancelled	$ 27.60	$ 25.18
Weighted-Average Grant-Date Fair Value, Ending balance	$ 29.06	$ 29.01