Summary Financial Information (Statements of Operations and (Accumulated Deficit) Retained Earnings) (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
Net sales	$ 146,472	$ 149,863	$ 299,485	$ 289,623
Cost of products sold	104,070	110,632	213,259	214,750
Gross Profit	42,402	39,231	86,226	74,873
Selling, general and administrative expenses	28,993	26,408	59,538	53,886
Restructuring charges	0		430	430
Amortization of intangibles	489	509	988	1,030
Total operating expenses	29,482	26,917	60,526	55,346
Operating Income Loss	12,920	12,314	25,700	19,527
Interest and debt expense	3,505	3,557	7,004	7,061
Other (income) and expense, net	(365)	(387)	(1,303)	(812)
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	9,780	9,144	19,999	13,278
Income Tax Expense Benefit	1,528	2,877	3,311	4,232
Income from discontinued operations		409	0	409
Equity in income from continuing operations of subsidiaries			0	0
Net income (loss)	8,252	6,676	16,688	9,455
Parent Company [Member]
Net sales	57,560	55,119	116,730	103,541
Cost of products sold	40,826	40,415	84,230	77,803
Gross Profit	16,734	14,704	32,500	25,738
Selling, general and administrative expenses	9,692	9,420	20,329	16,793
Restructuring charges	0			12
Amortization of intangibles	24	27	47	54
Total operating expenses	9,716	9,447	20,376	16,859
Operating Income Loss	7,018	5,257	12,124	8,879
Interest and debt expense	2,746	3,398	6,098	6,478
Other (income) and expense, net	(118)	(254)	(170)	(406)
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	4,390	2,113	6,196	2,807
Income Tax Expense Benefit	623	1,229	(233)	1,364
Income from discontinued operations				409
Equity in income from continuing operations of subsidiaries	4,485	5,383	10,259	7,603
Net income (loss)	8,252	6,676	16,688	9,455
Guarantor Subsidiaries [Member]
Net sales	39,624	44,889	83,199	86,860
Cost of products sold	33,243	39,705	69,836	75,418
Gross Profit	6,381	5,184	13,363	11,442
Selling, general and administrative expenses	5,102	3,352	11,131	9,752
Restructuring charges				0
Amortization of intangibles				0
Total operating expenses	5,102	3,352	11,131	10,686
Operating Income Loss	1,279	1,832	2,232	1,690
Interest and debt expense	632	65	684	406
Other (income) and expense, net	5	11	16	18
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	642	1,756	1,532	1,266
Income Tax Expense Benefit	0	200	80	169
Equity in income from continuing operations of subsidiaries				0
Net income (loss)	642	1,556	1,452	1,097
Non-Guarantor Subsidiaries [Member]
Net sales	63,192	65,034	127,186	126,371
Cost of products sold	43,905	45,691	86,823	88,678
Gross Profit	19,287	19,343	40,363	37,693
Selling, general and administrative expenses	14,199	13,636	28,078	27,341
Restructuring charges	0			418
Amortization of intangibles	465	482	941	976
Total operating expenses	14,664	14,118	29,019	28,735
Operating Income Loss	4,623	5,225	11,344	8,958
Interest and debt expense	127	94	222	177
Other (income) and expense, net	(252)	(144)	(1,149)	(424)
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments	4,748	5,275	12,271	9,205
Income Tax Expense Benefit	905	1,448	3,464	2,699
Equity in income from continuing operations of subsidiaries				0
Net income (loss)	3,843	3,827	8,807	6,506
Consolidation, Eliminations [Member]
Net sales	(13,904)	(15,179)	(27,630)	(27,149)
Cost of products sold	(13,904)	(15,179)	(27,630)	(27,149)
Gross Profit		0	0	0
Selling, general and administrative expenses				0
Restructuring charges				0
Amortization of intangibles			0	0
Total operating expenses			0	0
Operating Income Loss		0		0
Interest and debt expense				0
Other (income) and expense, net			0	0
Income Loss From Continuing Operations Before Income Taxes Minority Interest And Income Loss From Equity Method Investments		0	0	0
Income Tax Expense Benefit		0	0	0
Equity in income from continuing operations of subsidiaries	(4,485)	(5,383)	(10,259)	(7,603)
Net income (loss)	$ (4,485)	$ (5,383)	$ (10,259)	$ (7,603)