Summary of Significant Accounting Policies - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 163,412	$ 160,577	$ 158,665
Less - Accumulated depreciation and amortization	(112,071)	(109,657)	(105,532)
Net property, plant and equipment	51,341	50,920	53,133
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment	5,738	5,738	7,025
Buildings, leasehold interests and improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment	40,918	40,893	45,348
Machinery, equipment and other
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 116,756	$ 113,946	$ 106,292