Guarantees, Other Contingent Liabilities, And Other Matters (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2016
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Face amount of guarantee including unpaid accrued interest	$ 33,000	$ 26,000	$ 13,000
Fair value of the guarantees	1,722	1,356	1,628
Other contingent liabilities	2,000
Advances to suppliers current and non-current	78,000	71,000	134,000
Valuation allowance amount related to advances to suppliers	28,000	27,000	29,000
Net provision for losses (recoveries) on advances and guaranteed loans to suppliers	(2,038)	(4,354)
Aggregate balance of recoverable value added tax credits	35,000	52,000	52,000
Valuation allowance on recoverable value added tax credits	10,000	$ 21,000	$ 19,000
Santa Catarina [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Brazil audit assessment for tax, penalties, and interest on recoverable value added tax credits	15,000
Reduced Brazil audit assessment for tax, penalties, and interest on recoverable value added tax credits	14,000
Santa Catarina [Member] | Minimum [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Estimate of possible loss on remaining VAT audit assessment	0
Santa Catarina [Member] | Maximum [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Estimate of possible loss on remaining VAT audit assessment	14,000
Parana [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Brazil audit assessment for tax, penalties, and interest on recoverable value added tax credits	17,000
Reduced Brazil audit assessment for tax, penalties, and interest on recoverable value added tax credits	5,000
Parana [Member] | Minimum [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Estimate of possible loss on remaining VAT audit assessment	0
Parana [Member] | Maximum [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Estimate of possible loss on remaining VAT audit assessment	$ 5,000