Restructuring and Asset Impairment Charges Employee Separation and Other Cash 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
Period charges	246	19,337	0
Payments through March 31	(4,479)	(13,144)	(103)
Non-cash charges	760	4,130	0
Ending balance	1,960	6,193	0
South America [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	1,073	0	0
Period charges	75	7,589	0
Payments through March 31	(965)	(6,516)	0
Non-cash charges		2,860
Ending balance	183	1,073	0
Other regions [Member]
Restructuring Reserve [Roll Forward]
Beginning balance	5,120	0	103
Period charges	171	11,748	0
Payments through March 31	(3,514)	(6,628)	(103)
Non-cash charges	760	1,270
Ending balance	$ 1,777	$ 5,120	$ 0