Operating Segments (Schedule Of Sales And Long-Lived Assets By Country) (Details) - USD ($) $ in Thousands	12 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2020
Segment Reporting Information [Line Items]
Sales and other operating revenues	$ 2,103,601	$ 1,983,357	$ 1,909,979
Long-Lived Assets	651,687	594,865	459,840
United States [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	495,322	369,074	221,428
Long-Lived Assets	344,276	266,258	145,764
Belgium [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	283,072	366,476	361,889
Poland
Segment Reporting Information [Line Items]
Sales and other operating revenues	90,270	97,001	84,011
Germany [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	93,057	94,519	104,525
Philippines
Segment Reporting Information [Line Items]
Sales and other operating revenues	147,876	94,493	68,143
China [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	97,826	52,837	105,683
Netherlands
Segment Reporting Information [Line Items]
Sales and other operating revenues	45,297	40,754	55,532
Brazil [Member]
Segment Reporting Information [Line Items]
Long-Lived Assets	136,653	134,909	138,157
Mozambique [Member]
Segment Reporting Information [Line Items]
Long-Lived Assets	40,228	44,206	42,964
All Other Countries [Member]
Segment Reporting Information [Line Items]
Sales and other operating revenues	850,881	868,203	908,768
Long-Lived Assets	$ 130,530	$ 149,492	$ 132,955