Pension and Postretirement Benefits Net Periodic Pension Costs (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Defined Benefit Plan Disclosure [Line Items]
Accrued current benefit liability		$ 4,172
Contributions by employer	2,599
Service cost	512	614
Interest cost	1,842	2,140
Expected return on plan assets	(1,569)	(1,637)
Amortization of prior service (credit) cost	55	27
Defined Benefit Plan, Actuarial Gain (Loss)	498	306
Curtailment loss (gain)	0	(4,989)
Net periodic pension cost (benefit)	1,338	(3,539)
Additional contributions to the plans are expected during the rest of fiscal 2013	7,163
MALAWI | Foreign Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Curtailment loss (gain)	$ (4,989)