Employee Benefits A Reconciliation of Benefit Obligations (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2010
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Employer contributions	$ 4,705	$ 4,531	$ 4,062
Accrued noncurrent benefit liability recorded in Pension, Postretirement and Other Long-Term Liabilities	121,128	118,983
U.S. Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning	96,233	92,258
Service cost	1,807	2,113	1,666
Interest cost	4,782	4,879	5,352
Plan amendments	1,496	0
Plan curtailments	0	0
Actuarial losses	7,638	2,786
Settlements/special termination benefits	0	259
Effects of currency translation	0	0
Net transfers in	0	324
Benefits paid	(7,270)	(6,386)
Benefit obligation, ending	104,686	96,233	92,258
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning	45,256	41,867
Actual return on plan assets	910	4,120
Employer contributions	6,191	5,655
Plan settlements	0	0
Effects of currency translation	0	0
Fair value of plan assets, ending	45,087	45,256	41,867
Net amount recognized	(59,599)	(50,977)
Noncurrent benefit asset recorded in Other Noncurrent Assets	0	0
Accrued current benefit liability recorded in Accrued Expenses and Other Current Liabilities	(2,784)	(2,756)
Accrued noncurrent benefit liability recorded in Pension, Postretirement and Other Long-Term Liabilities	(56,815)	(48,221)
Non-U.S. Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning	67,872	64,237
Service cost	362	1,108	1,969
Interest cost	3,410	3,951	3,784
Plan amendments	0	0
Plan curtailments	(6,455)	0
Actuarial losses	1,654	2,431
Settlements/special termination benefits	956	204
Effects of currency translation	(1,045)	1,895
Net transfers in	0	0
Benefits paid	(5,189)	(5,954)
Benefit obligation, ending	61,565	67,872	64,237
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning	41,554	36,839
Actual return on plan assets	1,111	3,737
Employer contributions	5,388	6,038
Plan settlements	0	(358)
Effects of currency translation	(33)	1,252
Fair value of plan assets, ending	42,831	41,554	36,839
Net amount recognized	(18,734)	(26,318)
Noncurrent benefit asset recorded in Other Noncurrent Assets	0	1,353
Accrued current benefit liability recorded in Accrued Expenses and Other Current Liabilities	(2,091)	(3,155)
Accrued noncurrent benefit liability recorded in Pension, Postretirement and Other Long-Term Liabilities	(16,643)	(24,516)
Malawi [Member] | Non-U.S. Pension Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Plan curtailments	(4,989)
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Accrued current benefit liability recorded in Accrued Expenses and Other Current Liabilities		$ 4,172