Goodwill and Intangible Assets (Narrative) (Details)	3 Months Ended		6 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Reporting_Unit	Sep. 30, 2019 USD ($)	Mar. 31, 2020 USD ($)
Goodwill [Line Items]
Number of Reporting Units | Reporting_Unit			2
Amortization of intangibles	$ 3,192,000	$ 3,226,000	$ 6,307,000	$ 6,479,000
Goodwill	330,859,000		330,859,000		$ 319,679,000
Finite-Lived Intangible Assets, Amortization Expense, Remainder of Fiscal Year	12,600,000		12,600,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two	12,600,000		12,600,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three	12,600,000		12,600,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four	12,600,000		12,600,000
Finite-Lived Intangible Assets, Amortization Expense, Year Five	12,600,000		12,600,000
Indefinite-Lived Trademarks	47,841,000		47,841,000		46,670,000
Goodwill, Impaired, Accumulated Impairment Loss	113,174,000		113,174,000		113,174,000
Rest of Products [Member]
Goodwill [Line Items]
Goodwill	321,198,000		321,198,000		310,086,000
Duff Norton Group [Member]
Goodwill [Line Items]
Goodwill	$ 9,661,000		$ 9,661,000		$ 9,593,000
Forecast [Member]
Goodwill [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			18 years
Forecast [Member] | Trademark
Goodwill [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			15 years
Forecast [Member] | Customer relationships
Goodwill [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			18 years
Forecast [Member] | Other Intangible Assets [Member]
Goodwill [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			5 years
Forecast [Member] | Technology-Based Intangible Assets [Member]
Goodwill [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life			18 years