Condensed Consolidated Statements of Operations and Retained Earnings - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues [Abstract]
Net sales	$ 151,925	$ 146,041	$ 300,938	$ 282,277
Cost of products sold	102,196	99,096	203,162	191,748
Gross profit	49,729	46,945	97,776	90,529
Operating Expenses [Abstract]
Selling expenses	19,032	17,399	37,846	33,997
General and administrative expenses	16,313	22,040	32,595	37,142
Amortization of intangibles	1,765	994	3,515	1,587
Total operating expenses	37,110	40,433	73,956	72,726
Income from operations	12,619	6,512	23,820	17,803
Other Income & Expenses [Abstract]
Interest and debt expense	2,525	1,632	5,099	2,788
Investment (income) loss	(88)	(376)	(305)	(504)
Foreign currency exchange (gain) loss	(220)	1,459	(783)	1,274
Other (income) expense, net	(48)	(108)	(128)	(113)
Income before income tax expense	10,450	3,905	19,937	14,358
Income Tax Expense Benefit [Abstract]
Income tax expense	3,634	4,353	6,720	7,895
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	6,816	(448)	13,217	6,463
Retained Earnings Accumulated Deficit [Abstract]
Retained earnings - beginning of period	180,574	164,722	174,173	157,811
Retained earnings - end of period	$ 186,582	$ 163,470	$ 186,582	$ 163,470
Weighted Average Number Of Shares Outstanding Basic [Abstract]
Average basic shares outstanding	20,202,000	20,086,000	20,169,000	20,054,000
Weighted Average Number Of Shares Outstanding [Abstract]
Average diluted shares outstanding	20,368,000	20,086,000	20,325,000	20,277,000
Earnings Per Share Basic [Abstract]
Basic income (loss) per share:	$ 0.34	$ (0.02)	$ 0.66	$ 0.32
Earnings Per Share Diluted [Abstract]
Diluted income (loss) per share:	$ 0.33	$ (0.02)	$ 0.65	$ 0.32
Dividends	$ (808)	$ (804)	$ (808)	$ (804)
Common Stock, Dividends, Per Share, Declared	$ 0.04	$ 0.04	$ 0.04	$ 0.04