Condensed Consolidated Statements of Operations and Retained Earnings - USD ($)	3 Months Ended		9 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2019	Dec. 31, 2018
Revenues [Abstract]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 199,355,000	$ 217,415,000	$ 619,676,000	$ 659,549,000
Cost of Goods and Services Sold	131,483,000	144,010,000	402,699,000	430,597,000
Gross Profit	67,872,000	73,405,000	216,977,000	228,952,000
Operating Expenses [Abstract]
Selling expenses	23,169,000	23,858,000	68,801,000	73,940,000
General and administrative expenses	17,960,000	20,379,000	56,713,000	61,893,000
Research and Development Expense	2,628,000	3,271,000	8,419,000	10,137,000
Impairment of Long-Lived Assets to be Disposed of	0	15,550,000	176,000	26,650,000
Amortization of intangibles	3,229,000	3,701,000	9,708,000	11,358,000
Operating Expenses	46,986,000	66,759,000	143,817,000	183,978,000
Income from operations	20,886,000	6,646,000	73,160,000	44,974,000
Other Income & Expenses [Abstract]
Interest and debt expense	3,423,000	4,330,000	11,034,000	13,185,000
Investment (income) loss	(408,000)	82,000	(939,000)	(297,000)
Foreign currency exchange (gain) loss	188,000	(25,000)	(518,000)	206,000
Other (income) expense, net	199,000	(70,000)	618,000	(417,000)
Income Tax Expense Benefit [Abstract]
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	17,484,000	2,329,000	62,965,000	32,297,000
Income tax expense	2,234,000	3,111,000	12,537,000	9,461,000
Net income (loss)	15,250,000	(782,000)	50,428,000	22,836,000
Retained Earnings Accumulated Deficit [Abstract]
Retained earnings - beginning of period	270,218,000	221,239,000	236,459,000	197,897,000
Retained earnings - end of period	$ 284,047,000	$ 219,289,000	$ 284,047,000	$ 219,289,000
Weighted Average Number Of Shares Outstanding Basic [Abstract]
Average basic shares outstanding	23,679,000	23,348,000	23,581,000	23,245,000
Weighted Average Number Of Shares Outstanding [Abstract]
Average diluted shares outstanding	24,031,000	23,348,000	23,925,000	23,647,000
Earnings Per Share Basic [Abstract]
Basic income per share:	$ 0.64	$ (0.03)	$ 2.14	$ 0.98
Earnings Per Share Diluted [Abstract]
Diluted income per share:	0.63	(0.03)	2.11	0.97
Common Stock, Dividends, Per Share, Declared	$ 0.06	$ 0.05	$ 0.12	$ 0.10