Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Oct. 01, 2017	Sep. 30, 2018	Oct. 01, 2017
Disaggregation of Revenue [Line Items]
Revenue	$ 145,324	$ 125,395	$ 295,124	$ 259,126
Bulk / Distributed products [Member]
Disaggregation of Revenue [Line Items]
Revenue	49,982		100,268
Specialty / Manufactured products [Member]
Disaggregation of Revenue [Line Items]
Revenue	93,479		191,027
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,863		3,829
Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue	69,402	58,689	143,420	122,716
Industrial [Member] | Bulk / Distributed products [Member]
Disaggregation of Revenue [Line Items]
Revenue	14,532		28,257
Industrial [Member] | Specialty / Manufactured products [Member]
Disaggregation of Revenue [Line Items]
Revenue	53,610		112,461
Industrial [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,260		2,702
Water Treatment [Member]
Disaggregation of Revenue [Line Items]
Revenue	42,713	38,217	83,582	76,441
Water Treatment [Member] | Bulk / Distributed products [Member]
Disaggregation of Revenue [Line Items]
Revenue	5,826		11,710
Water Treatment [Member] | Specialty / Manufactured products [Member]
Disaggregation of Revenue [Line Items]
Revenue	36,414		70,967
Water Treatment [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	473		905
Health and Nutrition [Member]
Disaggregation of Revenue [Line Items]
Revenue	33,209	$ 28,489	68,122	$ 59,969
Health and Nutrition [Member] | Bulk / Distributed products [Member]
Disaggregation of Revenue [Line Items]
Revenue	29,624		60,301
Health and Nutrition [Member] | Specialty / Manufactured products [Member]
Disaggregation of Revenue [Line Items]
Revenue	3,455		7,599
Health and Nutrition [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 130		$ 222