Restructuring and Asset Impairment Charges Restructuring and Asset Impairment Charges (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Restructuring Reserve [Roll Forward]
Beginning balance	$ 6,193	$ 0	$ 103
Employee separation charges	215	13,474	0
Other cash charges	31	5,863	0
Total employee separation and other cash charges	246	19,337	0
Payments through March 31	(4,479)	(13,144)	(103)
Ending balance	1,960	6,193	0
Asset impairment and other non-cash charges	760	4,130	0
Total restructuring and asset impairment charges	$ 1,006	$ 23,467	$ 0