Intangible Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 71,968	$ 73,989
Finite-Lived Intangible Assets, Accumulated Amortization	(60,533)	(58,365)
Finite-Lived Intangible Assets, Net	11,435	15,624
Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	1,530	1,530
Finite-Lived Intangible Assets, Accumulated Amortization	(1,530)	(1,530)
Finite-Lived Intangible Assets, Net	0	0
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	23,260	24,867
Finite-Lived Intangible Assets, Accumulated Amortization	(14,320)	(13,547)
Finite-Lived Intangible Assets, Net	8,940	11,320
Product Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	45,195	45,234
Finite-Lived Intangible Assets, Accumulated Amortization	(43,034)	(41,431)
Finite-Lived Intangible Assets, Net	2,161	3,803
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	510	510
Finite-Lived Intangible Assets, Accumulated Amortization	(510)	(510)
Finite-Lived Intangible Assets, Net	0	0
Trademarks and Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	1,473	1,848
Finite-Lived Intangible Assets, Accumulated Amortization	(1,139)	(1,347)
Finite-Lived Intangible Assets, Net	$ 334	$ 501