Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Apr. 02, 2017	Jan. 01, 2017	Oct. 02, 2016	Jul. 03, 2016	Apr. 03, 2016	Dec. 27, 2015	Sep. 27, 2015	Jun. 28, 2015	Apr. 02, 2017	Apr. 03, 2016	Mar. 29, 2015
Summary of Segment Information
Sales		$ 118,618	$ 112,351	$ 121,250	$ 131,374	$ 129,513	$ 88,375	$ 94,592	$ 101,496	$ 483,593	$ 413,976	$ 364,023
Gross profit		21,913	20,912	27,032	28,216	25,002	14,709	19,811	20,735	98,073	80,257	65,791
Selling, general, and administrative expenses		14,468	14,916	14,871	15,126	16,067	12,825	10,303	9,891	59,381	49,086	35,375
Operating income		7,445	$ 5,996	$ 12,161	$ 13,090	8,935	$ 1,884	$ 9,508	$ 10,844	38,692	31,171	30,416
Identifiable assets	[1]	404,524				403,967				404,524	403,967	194,017
Capital Expenditures										21,616	24,183	14,552
Industrial [Member]
Summary of Segment Information
Sales										238,555	251,749	249,066
Gross profit										38,886	37,967	33,619
Selling, general, and administrative expenses										21,818	22,137	19,793
Operating income										17,068	15,830	13,826
Identifiable assets	[1]	159,032				158,015				159,032	158,015	151,157
Capital Expenditures										(10,529)	(17,712)	(10,590)
Water Treatment [Member]
Summary of Segment Information
Sales										128,954	128,312	114,957
Gross profit										35,962	35,470	32,172
Selling, general, and administrative expenses										19,798	19,261	15,582
Operating income										16,164	16,209	16,590
Identifiable assets	[1]	53,445				50,013				53,445	50,013	42,860
Capital Expenditures										(7,777)	(6,306)	(3,962)
Health and Nutrition [Member]
Summary of Segment Information
Sales										116,084	33,915	0
Gross profit										23,225	6,820	0
Selling, general, and administrative expenses										17,765	7,688	0
Operating income										5,460	(868)	0
Identifiable assets	[1]	192,047				195,939				192,047	195,939	0
Capital Expenditures										(3,310)	(165)	0
Unallocated Amount to Segment [Member]
Summary of Segment Information
Identifiable assets		$ 13,100				$ 32,800				$ 13,100	$ 32,800	$ 53,700

[1] Unallocated assets, consisting primarily of cash and cash equivalents, investments and prepaid expenses, were $13.1 million at April 2, 2017, $32.8 million at April 3, 2016 and $53.7 million at March 29, 2015.