Restructuring and Asset Impairment Charges Restructuring and Asset Impairment Charges (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2011
Restructuring Reserve [Roll Forward]
Beginning balance	$ 1,960	$ 6,193	$ 0
Employee separation charges	(55)	215	13,474
Other cash charges	0	31	5,863
Total employee separation and other cash charges	(55)	246	19,337
Payments through March 31	(1,237)	(4,479)	(13,144)
Ending balance	668	1,960	6,193
Asset impairment and other non-cash charges	0	760	4,130
Total restructuring and asset impairment charges	$ (55)	$ 1,006	$ 23,467