Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Apr. 03, 2016	Dec. 27, 2015	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 28, 2014	Sep. 28, 2014	Jun. 29, 2014	Apr. 03, 2016	Mar. 29, 2015	Mar. 30, 2014
Segment Reporting Information [Line Items]
Sales	$ 129,513	$ 88,375	$ 94,592	$ 101,496	$ 93,281	$ 83,825	$ 88,881	$ 98,036	$ 413,976	$ 364,023	$ 348,263
Gross profit	25,002	14,709	19,811	20,735	15,531	13,642	18,122	18,496	80,257	65,791	61,600
Selling, general, and administrative expenses	16,067	12,825	10,303	9,891	9,532	8,697	8,271	8,875	49,086	35,375	33,510
Operating income	8,935	1,884	9,508	10,844	5,999	4,945	9,851	9,621	31,171	30,416	28,090
Net income	$ 4,859	$ 815	$ 5,678	$ 6,791	$ 3,900	$ 3,146	$ 6,147	$ 6,021	$ 18,143	$ 19,214	$ 18,094
Basic earnings per share	$ 0.46	$ 0.08	$ 0.54	$ 0.64	$ 0.37	$ 0.30	$ 0.58	$ 0.57	$ 1.72	$ 1.82	$ 1.72
Diluted earnings per share	$ 0.46	$ 0.08	$ 0.54	$ 0.64	$ 0.37	$ 0.30	$ 0.58	$ 0.57	$ 1.72	$ 1.81	$ 1.71
Stauber Preformance Ingredients [Member]
Segment Reporting Information [Line Items]
Business Combination, Acquisition Related Costs	$ 600	$ 2,700							$ 3,300
Industrial [Member]
Segment Reporting Information [Line Items]
Sales									251,749	$ 249,066	$ 244,888
Gross profit									37,967	33,619	32,041
Selling, general, and administrative expenses									22,137	19,793	19,781
Operating income									15,830	13,826	12,260
Water Treatment [Member]
Segment Reporting Information [Line Items]
Sales									128,312	114,957	103,375
Gross profit									35,470	32,172	29,559
Selling, general, and administrative expenses									19,261	15,582	13,729
Operating income									16,209	16,590	15,830
Health and Nutrition [Member]
Segment Reporting Information [Line Items]
Sales									33,915	0	0
Gross profit									6,820	0	0
Selling, general, and administrative expenses									7,688	0	0
Operating income									$ (868)	$ 0	$ 0