Guarantees, Other Contingent Liabilities, And Other Matters (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Nov. 04, 2020	Mar. 31, 2020
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Face amount of guarantee including unpaid accrued interest	$ 0	$ 5,000		$ 3,000
Fair value of the guarantees	0	137		103
Other contingent liabilities	1,000
Net provision for losses (recoveries) on advances and guaranteed loans to suppliers	348	(1,885)
Stock repurchase program authorized amount	100,000
Stock repurchase program remaining authorized repurchase amount	56,100
New Stock Repurchase Program [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Stock repurchase program authorized amount			$ 100,000
Advances to suppliers [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Advances to suppliers current and non-current	81,000	94,000		153,000
Valuation allowances	14,000	16,000		16,000
Net provision for losses (recoveries) on advances and guaranteed loans to suppliers	300	(1,900)
Recoverable value added tax credits [Member]
Guarantees, Other Contingent Liabilities, and Other Matters [Line Items]
Aggregate balance of recoverable value added tax credits	51,000	56,000		52,000
Valuation allowances	18,000	$ 20,000		$ 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	8,000
Reduced Brazil audit assessment for tax, penalties, and interest on recoverable value added tax credits	8,000
Loss contingency amount accrued	0
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	8,000
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	10,000
Reduced Brazil audit assessment for tax, penalties, and interest on recoverable value added tax credits	3,000
Loss contingency amount accrued	0
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	$ 3,000