Restructuring and Asset Impairment Charges Cash Payments by Year (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Restructuring Cost and Reserve [Line Items]
Employee separation and other cash charges	$ 246	$ 19,337	$ 0
Cash paid 2011	0	(13,144)	0
Cash paid 2012	(62)	(4,417)	0
Balance at	184	1,776	0
Total cash payments	$ (4,479)	$ (13,144)	$ (103)