Summary of Significant Accounting Policies - Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 122,984	$ 126,320	$ 126,197
Less - Accumulated depreciation and amortization	(97,215)	(100,827)	(100,343)
Net property, plant and equipment	25,769	25,493	25,854
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	2,508	2,508	2,508
Buildings, Leasehold Interests and Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	33,754	35,664	35,398
Machinery, Equipment and Other [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, Gross	$ 86,722	$ 88,148	$ 88,291