Revenue (Details) $ in Thousands	12 Months Ended
	Mar. 31, 2019 USD ($)
Disaggregation of Revenue [Line Items]
Revenues	$ 556,326
Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	281,860
Water Treatment [Member]
Disaggregation of Revenue [Line Items]
Revenues	149,490
Health and Nutrition [Member]
Disaggregation of Revenue [Line Items]
Revenues	124,976
Bulk / Distributed specialty products [Member]
Disaggregation of Revenue [Line Items]
Revenues	192,072
Bulk / Distributed specialty products [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	61,231
Bulk / Distributed specialty products [Member] | Water Treatment [Member]
Disaggregation of Revenue [Line Items]
Revenues	21,774
Bulk / Distributed specialty products [Member] | Health and Nutrition [Member]
Disaggregation of Revenue [Line Items]
Revenues	109,067
Manufactured, blended or repackaged products [Member]
Disaggregation of Revenue [Line Items]
Revenues	358,524
Manufactured, blended or repackaged products [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	216,582
Manufactured, blended or repackaged products [Member] | Water Treatment [Member]
Disaggregation of Revenue [Line Items]
Revenues	126,257
Manufactured, blended or repackaged products [Member] | Health and Nutrition [Member]
Disaggregation of Revenue [Line Items]
Revenues	15,685
Other [Member]
Disaggregation of Revenue [Line Items]
Revenues	5,730
Other [Member] | Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	4,047
Other [Member] | Water Treatment [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,459
Other [Member] | Health and Nutrition [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 224