Loss Contingencies (Narratives) (Details) - USD ($)	12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Loss Contingencies [Line Items]
Loss Contingency Accrual, Product Liability, Gross	$ 768,000
Loss Contingency Alleged Taxes Owed	7,500,000
Loss Contingency Alleged Taxes Owed Including Penalties And Interest	3,100,000
Accrual for Environmental Loss Contingencies	$ 1,143,000
Malpractice Loss Contingency, Discount Rate	65.00%
Aggregate amount of reserves	$ 11,944,000	$ 12,686,000	$ 13,582,000	$ 13,335,000
Per occurrence limits on self-insurance for general and product liability coverage	2,000,000
Per occurrence limits on self-insurance for general and product liability coverage for 2014 and thereafter	3,000,000
Coverage minimum	2,000,000
Coverage maximum	$ 6,000,000
Claims maximum period	37 years
Asbestos related aggregate liability	$ 4,753,000,000
Estimated asbestos related liability payments over the next 12 months	2,000,000
Product Liability Contingency, Third Party Recovery	2,650,000
Proceeds from Legal Settlements	381,000	484,000
Product related aggregate liability	6,423,000,000
Minimum
Loss Contingencies [Line Items]
Asbestos-related aggregate liability - Maximum	3,800,000
Maximum
Loss Contingencies [Line Items]
Asbestos-related aggregate liability - Maximum	6,900,000
Litigation Settlement, Amount Awarded from Other Party	1,650,000
Monsanto [Member]
Loss Contingencies [Line Items]
Estimated Litigation Liability	100,000
Other Noncurrent Liabilities [Member]
Loss Contingencies [Line Items]
Loss Contingency Accrual, Product Liability, Gross	8,444,000	$ 9,185,000
Accrued Liabilities
Loss Contingencies [Line Items]
Loss Contingency Accrual, Product Liability, Gross	3,500,000
Tax Year 2003/2004 [Member] | Minimum
Loss Contingencies [Line Items]
Loss Contingency Alleged Taxes Owed	2,100,000
Tax Year 2003/2004 [Member] | Maximum
Loss Contingencies [Line Items]
Loss Contingency Alleged Taxes Owed	2,900,000
Magnetek [Member]
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies	464,000
Magnetek [Member] | Bridgeport Facility [Member]
Loss Contingencies [Line Items]
Accrual for Environmental Loss Contingencies	$ 352,000