Goodwill and Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Mar. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Accumulated Amortization	$ (25,223)		$ (25,223)		$ (22,598)
Intangible Assets, Net (Including Goodwill)	55,170		55,170		59,907
Finite-Lived Intangible Assets, Net	39,957		39,957		44,433
Finite-Lived Intangible Assets, Gross	65,180		65,180		67,031
Intangible Assets, Gross (Excluding Goodwill)	80,393		80,393		82,505
Indefinite-Lived Trademarks	15,213		15,213		15,474
Intangible Assets, Net (Excluding Goodwill)	55,170		55,170		59,907
Goodwill	40,294		40,294		$ 40,294
Amortization of Intangible Assets	1,100	$ 1,100	3,400	$ 3,400
Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months	4,500		4,500
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	17,500		$ 17,500
Purchased Technology Customer Relationships And Patents [Member] | Weighted Average [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life			15 years 9 months 12 days		15 years 9 months 12 days
Patents [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Accumulated Amortization	(11,691)		$ (11,691)		$ (10,625)
Finite-Lived Intangible Assets, Net	14,971		14,971		16,037
Finite-Lived Patents, Gross	26,662		26,662		26,662
Amortization of Intangible Assets	400	400	1,100	1,100
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	7,900		7,900
Finite-Lived Intangible Assets, Amortization Expense, Year Four	1,400		1,400
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Accumulated Amortization	(13,310)		(13,310)		(11,735)
Finite-Lived Intangible Assets, Net	24,986		24,986		28,396
Finite-Lived Customer Relationships, Gross	38,296		38,296		$ 40,131
Amortization of Intangible Assets	700	$ 700	$ 2,300	$ 2,300
Finite-Lived Intangible Asset, Useful Life			12 years 3 months 12 days		12 years 3 months 12 days
Finite-Lived Intangible Assets, Amortization Expense, after Year Five	9,600		$ 9,600
Finite-Lived Intangible Assets, Amortization Expense, Year Four	3,100		3,100
Other Intangible Assets [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Accumulated Amortization	(222)		(222)		$ (238)
Finite-Lived Intangible Assets, Net	0		0		0
Other Finite-Lived Intangible Assets, Gross	222		222		238
Trademarks [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible Assets, Net (Excluding Goodwill)	$ 15,213		$ 15,213		$ 15,474