Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2012
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Net Sales	$ 339,922	$ 397,290	$ 690,298	$ 815,153
Gross Profit	52,596	62,374	104,181	132,176
Gross profit as percentage of sales	15.50%	15.70%	15.10%	16.20%
Income (loss) from operations	(6,787)	12,198	(2,916)	32,456
Total Assets	832,488		832,488		893,461
North America [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Net Sales	143,374	148,848	297,000	305,483
Gross Profit	18,499	20,991	42,101	43,603
Gross profit as percentage of sales	12.90%	14.10%	14.20%	14.30%
Income (loss) from operations	6,844	10,899	20,692	21,718
Total Assets	218,485		218,485		232,855
Europe [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Net Sales	118,771	151,988	244,219	318,830
Gross Profit	17,808	20,302	32,516	45,696
Gross profit as percentage of sales	15.00%	13.40%	13.30%	14.30%
Income (loss) from operations	(9,942)	8,341	(10,128)	19,948
Total Assets	335,512		335,512		370,824
South America [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Net Sales	34,222	48,095	65,373	96,016
Gross Profit	5,775	8,851	10,511	17,843
Gross profit as percentage of sales	16.90%	18.40%	16.10%	18.60%
Income (loss) from operations	4,255	2,687	4,962	5,877
Total Assets	89,922		89,922		96,588
Asia [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Net Sales	13,818	19,989	29,609	41,254
Gross Profit	23	1,820	440	4,906
Gross profit as percentage of sales	0.20%	9.10%	1.50%	11.90%
Income (loss) from operations	(2,335)	(750)	(4,597)	63
Total Assets	94,868		94,868		102,567
Commercial Products [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Net Sales	33,824	35,070	63,965	69,218
Gross Profit	10,124	10,261	18,021	19,790
Gross profit as percentage of sales	29.90%	29.30%	28.20%	28.60%
Income (loss) from operations	2,593	2,897	3,592	6,268
Total Assets	79,462		79,462		68,900
Segment net sales [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Net Sales	344,009	403,990	700,166	830,801
Corporate and Administrative [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Gross Profit	367	149	592	338
Gross profit as percentage of sales	0.00%	0.00%	0.00%	0.00%
Corporate and eliminations [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Net Sales	(4,087)	(6,700)	(9,868)	(15,648)
Income (loss) from operations	(8,202)	(11,876)	(17,437)	(21,418)
Total Assets	14,239		14,239		21,727
Segment income from operations [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Income (loss) from operations	1,415	24,074	14,521	53,874
Segment Gross Profit [Member]
Segment Reporting Information, Revenue for Reportable Segment [Abstract]
Gross Profit	$ 52,229	$ 62,225	$ 103,589	$ 131,838
Gross profit as percentage of sales	15.20%	15.40%	14.80%	15.90%