Goodwill and Intangible Assets (Narratives) (Details)	12 Months Ended
	Mar. 31, 2020 USD ($) Reporting_Unit	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2016 USD ($)
Finite-Lived Intangible Assets [Line Items]
Number of reporting units | Reporting_Unit	2
Goodwill	$ 319,679,000	$ 322,816,000	$ 347,434,000
Duff Norton reporting unit goodwill	9,593,000	9,611,000
Rest of products reporting unit goodwill	310,086,000	313,205,000
Impairment charges related to goodwill or intangible assets		0		$ 0
2016	12,400,000
2017	12,400,000
2018	12,400,000
2019	12,400,000
2020	$ 12,400,000
Weighted-average amortization periods	18 years
Indefinite-lived trademark	$ 46,670,000	46,981,000
Amortization of intangibles	12,942,000	14,900,000	15,552,000
Gain (Loss) on Disposition of Property Plant Equipment	$ 0
Trademark
Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization periods	15 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived	$ 2,815,000
Weighted-average amortization periods	18 years
Acquired technology
Finite-Lived Intangible Assets [Line Items]
Weighted-average amortization periods	18 years
Other
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived	$ 226,000
Weighted-average amortization periods	5 years
Goodwill [Member]
Finite-Lived Intangible Assets [Line Items]
Gain (Loss) on Disposition of Property Plant Equipment		$ 6,174,000	$ 0
Other | Reduced Depreciation [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived	$ 211,000
Customer relationships | Reduced Depreciation [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Intangible Assets, Finite-lived	$ 957,000