Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 29, 2019	Sep. 30, 2018	Sep. 29, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Revenue	$ 140,043	$ 145,324	$ 287,379	$ 295,124
Bulk / Distributed specialty products [Member]
Disaggregation of Revenue [Line Items]
Revenue	39,563	50,913	83,964	102,348
Manufactured, blended or repackaged products [Member]
Disaggregation of Revenue [Line Items]
Revenue	99,182	93,008	200,870	189,884
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	1,298	1,403	2,545	2,892
Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenue	68,090	69,402	143,415	143,420
Industrial [Member] | Bulk / Distributed specialty products [Member]
Disaggregation of Revenue [Line Items]
Revenue	11,700	15,307	26,790	30,243
Industrial [Member] | Manufactured, blended or repackaged products [Member]
Disaggregation of Revenue [Line Items]
Revenue	55,506	53,204	114,900	111,236
Industrial [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	884	891	1,725	1,941
Water Treatment [Member]
Disaggregation of Revenue [Line Items]
Revenue	45,868	42,713	89,120	83,582
Water Treatment [Member] | Bulk / Distributed specialty products [Member]
Disaggregation of Revenue [Line Items]
Revenue	4,971	5,982	9,679	11,804
Water Treatment [Member] | Manufactured, blended or repackaged products [Member]
Disaggregation of Revenue [Line Items]
Revenue	40,487	36,305	78,637	70,964
Water Treatment [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	410	426	804	814
Health and Nutrition [Member]
Disaggregation of Revenue [Line Items]
Revenue	26,085	33,209	54,844	68,122
Health and Nutrition [Member] | Bulk / Distributed specialty products [Member]
Disaggregation of Revenue [Line Items]
Revenue	22,892	29,624	47,495	60,301
Health and Nutrition [Member] | Manufactured, blended or repackaged products [Member]
Disaggregation of Revenue [Line Items]
Revenue	3,189	3,499	7,333	7,684
Health and Nutrition [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue	$ 4	$ 86	$ 16	$ 137